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A STUDY OF THE UNITED STATES NAVY'S MINESWEEPING
EFFORTS IN THE KOREAN WAR
by
STEPHEN DWIGHT BLANTON, B.A.
A THESIS
IN
HISTORY
Submitted to the Graduate Faculty of Texas Tech University in
Partial Fulfillment of the Requirements for
the Degree of
MASTER OF ARTS
Approved
Accepted
August, 1993
ACKNOWLEDGEMENTS
I would like to take this opportunity to thank those
people who have helped in the research and writing of this
paper. Foremost, I want to thank Dr. James R. Reckner for his
patience and aid in guiding my work. I would also like to
thank Dr. Donald Walker for looking over the paper to help
refine it. The aid, given to me by Dr. Edward J. Marelda,
Cathy Lloyd, and everyone else at the Operational Archives of
the Naval Historical Center in locating documents, was
invaluable. Without the help of these people, this paper
would not have been possible.
ii
TABLE OF CONTENTS
ACKNOWLEDGEMENTS ....................................... ii
LIST OF TABLES ......................................... iv
L I S T OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
CHAPTER
I . INTRODUCTION ................................... 2
II. POST-WAR TO THE KOREAN WAR .................... 11
III.FORMING OF A NEW STRATEGY ..................... 38
IV. THE SIEGE OF WONSAN AND THE FLOATING MINE THREAT .................. 77
V. AFTERMATH AND CONCLUSION ...................... 97
ENDNOTES ............................................... 105
BIBLIOGRAPHY ........................................... 117
APPENDICES
A. UNITS ASSIGNED TO CTG 95.6 MINESWEEPING FORCE DURING THE KOREAN WAR ................... 122
B. SHIP STATISTICS ............................... 125
C. TASK ORGANIZATIONS FOR THE INCHON, WONSAN, AND CHINNAMPO SWEEPS .......... 127
D. AVAILABLE MINESWEEPERS IN THE FAR EAST ........ 129
E. MINES SWEPT ................................... 130
F. UNITED NATIONS SHIPS SUNK AND DAMAGED IN KOREAN WATERS .............................. 132
LIST OF TABLES
1 ESTIMATED INFLUENCE OF OCEANOGRAPHIC FACTORS IN MINE WARFARE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 COMPARISON OF OCEANOGRAPHIC CONDITION ON COASTS OF KOREA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 0
3 COMPARISON OF MINE WARFARE OPERATIONS ON COASTS OF KOREA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4 NUMBER OF FLOATING MINES SIGHTED .................. 95
iv
LIST OF FIGURES
1. THE SITUATION DURING THE FIRST YEARS OF THE WAR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. MODIFIED MOORED SWEEPING GEAR AND MAGNETIC SWEEPING GEAR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 6
3. P'OHANG-DONG SWEEP ............................... 27
4. THE MINE SITUATION IN 1950... . . . . . . . . . . . . . . . . . . . . 33
5 . KUNSAN SWEEP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 7
6. WONSAN APPROACHES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
7 . WON SAN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
8 . CHINNAMPO SWEEP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
9. CHINNAMPO APPROACHES ............................. 61
10 . CHINNAMPO. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5
11 . HUNGNAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7
12. EAST COAST COASTAL SWEEP FROM YANGYANG TO SUWON DAN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5
13. EAST COAST COASTAL SWEEP FROM SUWON DAN TO SONGJIN AREA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 6
14. MINE SIGHTINGSS AND DESTRUCTION, 1950 ........... 87
15. MINES SIGHTED AND SWEPT, 1950-51 ................ 89
16. MINES SIGHTED AND SWEPT, 1951 ................... 90
17. MINE SIGHTINGS, 1951 ............................ 92
18 . MINE SIGHT INGS , 19 51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3
v
CHAPTER I
INTRODUCTION
The main problems the United States Navy faced when the
Korean War began on June 25, 1950, were a lack of equipment,
a lack of ships, and a lack of experienced personnel (see
Figure 1) . The causes of these problems were military
demobilization after World War II and the massive budgetary
cutbacks drafted by Congress in the post-war years in an
attempt to realize a "peace dividend." The combined effect of
demobilization and fiscal constraint upon the navy's
efficiency immediately became apparent when the United States
entered;the Korean War. Admiral Charles K. Duncan, Commander
in Chief, Atlantic Fleet (CINCLANTFLT) during the war,
considered ludicrous the idea that the United States only
needed to maintain an amphibious or mine force on one coast to
maintain and develop the retained technologies and skills, yet
"that is exactly what was done and we paid heavily for it." 1
Minesweepers comprised an important facet of the war
effort. The reduced minesweeping force became part of the
United Nations Blockade and Escort Force. 2 Their job was to
clear the assault beaches for amphibious landings and to sweep
fire support channels so the battleships, cruisers, and
destroyers could get close inshore to bombard the enemy. 3
Throughout the war the bombarding naval forces poured over 70
million pounds of high explosives onto enemy positions causing
1
SEA OF JAPAN
YELLOW SEA
-)60 f-(I)
4J
i!3 " Q:'
~
-3~·
Figure 1. THE SITUATION DURING THE FIRST YRARS OF THE WAR source: CINCPACFLT Interim Evaluation Report J.
2
an estimated 57,000 casualties and a large amount of material
damage. 4
It is accepted that "minable waters are considered to be
those whose depth does not exceed 10 0 fathoms. "5 In Korea
this posed a tremendous problem for minesweepers as "nowhere
in the Yellow Sea is the water more than 60 fathoms in depth,
and within 10 miles of the shore it is less than 20 fathoms." 6
This extensive minable area and the prevailing currents around
Korea created a virtual nightmare for minesweepers. The
currents, which reached speeds of five knots on the west
coast, tore up many mines' mooring cables and shifted other
moored mines from their original positions. This created
irregular minefields, which were more difficult to clear (see
Table 1) .
Many of the mines laid by the North Koreans and later
swept by the United States Navy were of Russian origin. Some
of the mines were of 1904 vintage, while the majority were
from the inter-war period, laid by fishing sampans and junks.
In tandem with these old moored contact mines were new ground
influence mines. By mixing the two types the enemy "presented
a new menace to the minesweeper. " 7 The ships found it
difficult to sweep one type in the presence of another.
Fortunately for the navy, the North Koreans were given
very few influence mines. "There is no doubt that if the
enemy had sown a large number of pressure and pressure
3
~
T.lB
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81
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6,
11
21
-1
12
2.
magnetic combination type mines, our countermeasure capability
would have been severely taxed." 8
Despite the post-war cutbacks, the United States still
maintained the strongest navy in the world. Yet, even with
its offensive might its amphibious force was compelled to wait
outside Wonsan harbor "while a few minesweepers struggled to
clear it. " 9
When the Second World War ended, the U.S. Navy had over
500 minesweepers and about 33,000 men in the Pacific mine
force alone. For the Korean War, the entire American mine
warfare force totalled two divisions of destroyer
minesweepers, two divisions of minesweepers, and 21 smaller
ships. Many of these vessels were far from the theater of
conflict. Pitifully few ships were available considering that
"around the embattled Korean peninsula, shallow, minable
waters stretched for 11,000 miles." 10 By mid-October, without
endangering any ships larger than the fishing junks and
sampans used to lay the mines, "the Communists sank five U.S.
and two Korean ships, damaged several more, and rocked the
Pentagon" when Chief of Naval Operations, Admiral Forrest P.
Sherman, received Rear Admiral Allen E. Smith's message
reporting that the navy had "lost control of the sea." 11
The reason America "lost control of the sea" could be
seen in the force reductions imposed on the post-war navy by
Secretary of Defense Louis Johnson. The people's desire to
demobilize brought on a vicious budget war among the
6
individual branches of the armed services in defense of their
future roles. The newly independent air force claimed a
strategic bombing ideal that captured the imagination of the
country, thus, the navy received a disproportionately small
part of an even smaller budget.
The Russians, whose interest in mine warfare was deeply
imbedded in their traditionally defensive approach to naval
problems, capitalized on America's self-imposed mine warfare
weakness by taking this opportunity to inflict as much
physical damage as possible on the American fleet. In the
process they caused the United States to spend millions ~n new
research and construction at a cost to the Soviets of only a
few thousand antiquated mines. 12
The cost to the United States in lives and ships lost was
tremendous. In fact, "mines caused 70 percent of all U.S.
naval casualties during the first two years" of the 37 month
war. 13 By the war's end, mines sank a total of six navy, four
South Korean, and one Japanese ship, and damaged six navy,
three ROKN, and one Japanese ship. These losses could have
been averted had it not been for the cutbacks of earlier
years.
The Russian fascination with mines is almost as old as
the technology itself. They were especially adept at the use
of defensive minefields and floating mines (floaters) . During
the Crimean War (1854-1856), they used contact mines to
protect their harbors. Later in the Russo-Turkish War
7
(1877-1878), mines halted the Turkish fleet and gave the
initiative to the Russians . 14 Twenty-six years later, in 1904,
the Russo-Japanese War broke out. Eighteen warships sank due
to mines in that conflict. Russian and Japanese capital ships
were lost to the Russian minefields. Defensive minefields
kept the Japanese out of range of the Russian ports.
The extensive use of floating mines to wreak havoc with
the enemy's supplies and lines of communication was directly
responsible for the Hague Conference of 1907 banning their
use. 15 Article I of the eighth Hague Convention required
moored mines that broke loose from their moorings to disarm
themselves automatically and mines laid without moorings to
disarm themselves after one hour. 16 The disarming mechanism,
called a sterilizer, could even be specifically programmed to
disarm itself after a specified amount of time. 17
When World War I broke out in 1914, until his death in
1915, Russian Admiral Nikolai von Essen converted many vessels
to minelayers, which formed the backbone of the Russian mine
force for years to come. These ships laid offensive, as well
as defensive, minefields. Their efforts harassed the German
transports carrying ore from Sweden. 18 The Soviet Union
continued to lavish attention on the mine warfare community
throughout the inter-war years and during World War II. At
the end of the Second World War, the Soviets captured and kept
most of the German mine stocks, as well as their mine
personnel. The Soviets saw to the expansion and modernization
8
of Admiral von Essen's fleet during this time. They built
many new ships after the war and stressed mine warfare
education for all line officers. 19 American naval mine
countermeasures programs suffered by comparison. With many of
the specialists in the Reserves and the few ships spread
thinly, the United States fell far behind.
One of the most trying facets of mine clearance was
dealing with mines equipped with ship counters, devices which
enabled the mine to detonate after a preset number of vessels
had safely passed over. Defeating the ship counter required
additional check sweeps of already cleared areas. These check
sweeps required additional time and removed valuable ships
from combat, or first run, sweeps of other areas. Such
additional demands were particularly important for the United
States Navy, which was ill-equipped to meet the basic mine
clearance requirements. 20
Soviet directed defensive mining of North and South
Korean waters was carried out as the only available
counterbalance for the preponderant United Nations naval
strength. The North Korean Navy was insignificant and the
Soviet Navy, which had not yet begun its buildup to challenge
the United States Navy, was still weak and also faced
political constraints upon the exercise of its power. The
defensive minefields were established to prevent United
Nations vessels from making amphibious assaults. 21 If that
9
could be done, the North Korean Peoples Army (NKPA) could
fight on more equal terms with the U.N. forces.
The Conununists used mainly chemical horn and inertia
contact mines and also a few magnetic mines. Floaters were
used prolifically and constituted the major mine threat after
the war stalemated. Due to the United States forces'
unpreparedness to conduct mine countermeasures, initial losses
were very high. In the first few months, many small ships
were sunk or damaged, including five destroyers. 22 Mines also
caused delays, which were favorable only to the enemy. At
Wonsan, a fleet of 250 ships was delayed five days beyond
their scheduled landing date because of mines. 23 In modern
warfare where any delay might have catastrophic results, this
five days' delay constituted an unacceptable risk.
The United States Navy's minesweepers, always far too
few, acquitted themselves remarkably well. In order to
compensate for the chronic shortage of minesweepers, American
Navy men were compelled to improvise under fire and radically
alter minesweeping procedures. These efforts were vindicated
when the new method proved itself under fire.
10
CHAPTER II
POST-WAR TO THE KOREAN WAR
During the Second World War, the United States Navy had
had between 525 and 550 minesweepers 1n the Pacific
minesweeping fleet at any one time. 24 For the naval share of
the Normandy invasion, Operation Overlord, in June, 1944, the
allies had massed 306 minesweepers to clear the assault
beaches. Due to the ongoing demands of Pacific naval
operations, only 32 of the Overlord minesweepers were
American. In April, 1945, United States mine warfare forces
assigned to support the assault on Okinawa included 75
minesweepers and 45 assisting ships. They spent their first
week clearing 222 mines; over the next two months that total
was raised to 510. 25
When the Second World War ended, there was little
interest in keeping the massive military then in existence.
The great majority of the men who had enlisted "for the
duration," or who had been drafted, desired nothing more than
to return home to civilian life. And the Congress, which had
authorized massive deficit spending to conduct the war, now
sought to drastically reduce expenditures and return to pre
war funding levels. In the ensuing budget struggle over the
dwindling resources, the newly created air force prevailed
because of the glamour of the aircraft and the appeal of
11
their vision of limited warfare with planes doing all the
fighting, thereby reducing the horrifying casualties to our
own forces. The army and navy then had to fight over the
scraps in a desperate bid for survival, a situation which, in
hindsight, should never have developed.
Many of the ships of the massive wartime navy were sold,
scrapped, or placed in reserve fleets. 26 In the Far East, the
army cut back from 50,000 men to a mere 500 in the Republic of
Korea (ROK) . Immediately after the war "U.S. military
strength was reduced in an attempt to reach pre-World War II
levels, which had little connection with U.S. post-war
commitments overseas. " 27
Of the 374 minesweepers the navy had in the Pacific at
the beginning of 1946, a mere fourteen remained by the end of
the year. Their job was to observe the Japanese minesweepers
as they cleared the American and Japanese wartime minefields
in Japanese waters, after the Japanese sweepers completed
their sweep around the Philippines. 28 In March of that year,
the Mine Force Pacific Fleet command moved from Japan to San
Francisco. The navy scrapped almost all of the mine locator
ships (AMCU). The minesweeper tenders were soon to follow.
By 1950, two divisions of destroyer minesweepers (OMS), two
divisions of minesweepers (AM), twenty-one auxiliary
minesweepers (AMS), and two minesweeping boats (MSB), a total
of 37 minesweepers, comprised the entire available
12
minesweeping force. 29
reserve. 30
An additional 143 units remained in
Degaussing, a process whereby the magnetic signature of
a ship is reduced to a minimum as protection against magnetic
influence mines, "had not been kept up to date and there was
no degaussing range West of Pearl Harbor. " 31 Para vanes, which
cut moored contact mines allowing them to be destroyed, thus
protecting following ships, were removed from the ships.
Budget restraints limited training. 32
In 1947, Chief of Naval Operations (CNO) Fleet Admiral
Chester Nimitz dissolved the Mine Force Pacific Fleet
Command. 33 The Mine Force Atlantic Fleet remained. As Admiral
Charles K. Duncan said of the post-war cutbacks, "we were
greatly concerned with offensive mining as an anti-submarine
device. We were less concerned and had a fairly small force
for defensive mining minesweeping." 34
There were no more reductions in strength in 1948 but
training became a problem. Due to a shortage of fleet
destroyers, the destroyer minesweepers (DMS) were used almost
exclusively as destroyers. Most of the auxiliary minesweepers
(AMS) were spread thinly across the Pacific, which hampered
training. The only units actively training were the ships in
Japan, which were checking Japanese progress in sweeping the
old World War II minefields. 35 The destroyer minesweepers were
placed under the control of Commander, Cruiser-Destroyer Force
Pacific Fleet (COMCRUDESPAC), while the regular minesweepers
13
were under Commander, Service Division (COMSERVDIV) after Mine
Force Pacific Fleet was dissolved.
Some attention was still being paid to mine
countermeasures during this time. "By 1949 the Bureau of
Ships had produced design characteristics for a new non
magnetic fleet minesweeper with the operational capabilities
of both the converted wooden trawlers and the new steel AMs.
Plans for this new AM were shelved due to lack of funding in
fiscal year 1950. " 36
What the budgetary cutbacks left in the Far East in 1950
were "four 180 foot steel-hull, fleet minesweepers (three of
them ~n caretaker status), and six wooden auxiliary
minesweepers. " 37 The ships were undermanned because 99 percent
of the trained U.S. Navy mine personnel from the Pacific war
were in the reserves. 38 These were the vessels on hand when
the United States went to war in Korea.
Given this background, it is not surprising that the
minesweepers encountered difficulties in their attempts to
clear mines in Korea. At no time during the Korean War did
the available American minesweeping force exceed 27 ships. A
fleet one-fifth the size of that which cleared the assault
beaches around the tiny island of Okinawa was required to
clear and maintain the safety of the entire Korean peninsula.
By June, 1950, the Pacific fleet minesweeping force had
been reduced to 10 ships in Japan and 12 Japanese minesweepers
under contract, all of which had five years of post-war
14
sweeping behind them. 39 The number of minesweepers available
fluctuated with ships rotating in and out of the minesweeping
force. Thus, although there were 12 Japanese minesweepers
available, the number actually in service fluctuated from a
high of 10 to a low of one. In this manner, the minesweeping
fleet never rose above 24 active sweepers in the theater, as
arriving American ships relieved Japanese, ROKN, and other
American sweepers. There actually were 213 minesweepers of
various nationalities in the Pacific at the time.
Unfortunately, about half of them belonged to the Soviet
Union, which for obvious reasons would not use them in Korea.
Of the rest, many were unfit for duty, and, with the exception
of the U.S., ROK, and Japanese contract sweepers, none were
offered for U.N. service in Korea. 40 The three mine locator
ships (AMCU) were unavailable, being then in the Atlantic, and
there were no minesweeper tenders left in service as they had
been scrapped. 41
The Pacific Fleet stationed all four destroyer
minesweepers on the West coast for overhaul, while the three
AMSs were supposed to protect five strategic ports. Pearl
Harbor accounted for another three AMSs, those protecting
three ports. Guam's two AMSs protected Agana. Finally, the
19 active ships in Japanese waters were keeping three ports
open there. 42 The reserve fleet ships in the Pacific included
the 3 AMs in Japan, 5 commissioned reserve vessels, and 72
inactive reserve ships on the west coast. 43
15
The seven minesweepers initially available were listed as
inadequate for a combat sweep. Their war diary listed the
following deficiencies: ( 1) incapable of pressure
minesweeping, (2) no buoys to mark swept areas, (3) a lack of
ships, (4) a lack of reserve materials, (5) a lack of nearby
degaussing facilities, (6) inadequate intelligence on the
enemy's mining capability, (7) no mine disposal personnel, (8)
"no Mine and Counter Mine Technical Unit [MACTU] personnel
available ~n Pacific Ocean area," (9) no means of night
minesweeping of moored mines, and (10) inadequate sonar to
offer safe operation near moored minefields. 44 In short, the
forces were insufficient "to keep three ports open to the
fleet against a limited mining effort by an alert enemy." 45
Commander, Naval Forces Far East (COMNAVFE) consisted of
seven active ships when the war broke out in June, 1950. In
addition there were twelve other active United States
minesweepers in the Pacific. Of the four AMs in Japan, Pirate
(AM-275) and Incredible (AM-249) were soon ready for duty, but
Mainstay (AM-261) could not join them due to a lack of spare
parts. By late July, two of the four destroyer minesweepers
(DMS), Endicott (DMS-35) and Doyle (DMS-34), were dispatched
to the theater from the west coast. With the discovery of
mines in early September, five AMSs went west, while nine
minesweepers in reserve were ordered readied for duty. By
October 2, 1950, the last two DMSs, Thompson (DMS-38) and
16
Carmick (DMS-33), as well as the remaining three AMSs, sailed
for Korea. 46
Help was soon on the way. By September 30, 1950, there
were 21 active U.S. minesweepers available, with 14 AMS and
one AM ordered to report. 47 With these vessels, the losses
incurred due to mines could be replaced and ships could be
rotated as needed.
The Republic of Korea (ROK) also had a navy which could
help. They had one landing ship tank (LST), 15 former
American minesweepers, 10 former Japanese minesweepers, and
various other vessels g1. ven them under the Mutual Defense
Assistance Program (MDAP) . 48 They also had not been to a
degaussing range in a long time and, more significantly, they
lacked gear to sweep moored mines. 49
eager to help defend their seas.
Nevertheless, they were
The Chief of Naval
Operations authorized the equipping of 10 ROKN YMSs with
moored rninesweeping gear, as well as the training of the crews
at Sasebo. 50
In mine warfare, the Communists held a tremendous
advantage; they had only to lay defensive minefields to delay
an amphibious landing until their troops could arrive on the
scene. On August 29, 1950, the North Korean Navy's mine
expert, Lieutenant Cho Chun Hyon, left Chinnampo to begin the
mining of Inchon harbor. 51 The enemy laid mines in most South
Korean ports that carne under their control while United
Nations forces were contained within the Pusan Perimeter. 52
17
Many of the mines were laid by junks and fishing sampans, the
smaller sampans carrying only 2 to 4 mines per mission. 53
The North Korean mining effort did not begin until mid-
August, 1950. This delay in beginning mining and even in
receiving the mines from their Soviet sponsors indicates the
North Korean decision to mine was a reaction to United
States/United Nations intervention.
The approximately 4, 000 mines laid were Soviet-built.
They were shipped south by rail from Vladivostok beginning in
mid-July to Wonsan on the east coast of Korea and Chinnampo on
the west coast, from whence they were distributed by truck to
the various ports targeted for mining. Although later in the
war trains carrying mines were harassed by United Nations
aircraft and ships, these first shipments made it through.
Search planes had reported the presence of barges in the enemy
held ports, but at the time their presence was not interpreted
as an indication of mine laying. 54 By the time U.S. forces
moved to close the rail connections, Inchon, Chinnampo, Haeju,
Kunsan, Mokpo, Hungnam, Wonsan, and many lesser ports had
already been mined.
The predominant mines were the Russian MKB chemical horn
contact mine and the M2 6 inertia contact mine. Magnetic
ground mines were also laid. 55 Soviet naval officers went to
North Korea and even to Inchon to assist in training their
ally's troops in their use. In Wonsan and Chinnampo schools
18
were established to teach mine assembly.
helped assemble and lay the mines. 56
The advisors even
The Korean terrain greatly affected minability. The east
coast is regular, the 100 fathom curve close inshore, the
tidal range small, and the current is slow, ensuring the mines
will stay put. The clear water facilitates spotting mines
from the air. The west coast, on the other hand, has many
estuaries and rivers which are navigable for 100 miles or
more. The Yellow Sea is less than 60 fathoms deep and the
water is opaque; mines could be sown almost anywhere and would
be difficult to spot from the air. The massive tidal range,
averaging 21 feet, made mining difficult as at times the
moored mines were too far under water to be effective or were
completely exposed. The strong currents shifted the mines
around considerably and tore them up quickly. 57 Thus, east
coast mining was the better option (see Tables 2 and 3) .
United Nations forces first discovered mines on September
4, 1950, off Chinnampo. 58 From then until the end of the
month, mines were sighted on 54 occasions. Perhaps more
ominously, 25 floaters were also spotted. 59 From October 14
to 19, the number of floaters sighted jumped to 45 in the
areas between Chinnampo and Inchon on the west coast and
Hungnam and Yangyang on the east coast. 60 With a predominantly
southerly current, the floating mines represented a greater
danger than moored mines as their current-driven mobility
19
1\.J 0
Dot
tom
Ch
arac
ter
Tid
o R
ange
Tid
al C
urr
ents
'riin
ds
·,'/a
ves
Tra
npa.
renc
y
TABL
E 2
COM
PARI
SON
OF O
CEAN
GGRA
PHIC
CO
~~IT
ION
ON C
OAST
S OF
KOR
EA
WES
T CO
AST
vF K
OREA
Ex
ten
siv
e sh
oal
are
as w
ith
num
erou
s is
lan
ds
dis
sect
ed
by n
arro
w c
han
nel
s.
Bot
tom
G
ener
ally
mud
, sa
nd
and
som
e ro
Ck.
C
oast
dee
ply
in
den
ted
wit
h n\
lr.'le
ro\U
I ri
vers
.
Sp
rin
g t
ide r
ang
e be
twee
n 1
0 o
.nd
JO f
t.
wit
h m
axim
a n
ear
Inch
on a
nd
Yal
u R
iver
.
Gen
eral
ly s
tro
ng
and
p
art
icu
larl
y s
o in
ch
anne
ls
lead
irg
to
principP~
po
rts
(4 t
o
6 k
no
ts).
lio
rth
erly
in
win
ter
thro
ugh
was
terl
y t
o
sou
ther
ly 1
n su
mm
er.
In w
inte
r o.
vera
ee
forc
e 4.
So
mew
hat
wea
ker
in s
ur.tm
or.
!71t
h n
ort
her
ly w
inds
wav
es
wil
l be
lo
ss i
n p
rote
cted
ch
ll.""
.nel
s &
i.
n1,e
ts.
How
ever
ov
or s
ho
al a
reas
wav
es w
ill
be
stee
p &
wil
l b
reak
. Stron~
tid
nl
curr
ents
wil
l aff
ect
wnv
es.
~inter
turb
id d
ue
to r
iver
run
o
ff R
nd
mud
d
istu
rbed
by
wav
es.
EAST
COA
ST U
F KO
REA
Nar
row
sh
elt
wit
h t
ew i
slan
ds.
ll
otto
m u
sual
ly s
and
or
mud
w
ith
iso
late
d r
ooks
nea
r ab
ore
. C
oast
lin
e r
ela
tiv
ely
str
aig
ht
wit
h f
ew
nat
ura
l h
arb
ors
.
Sp
rin
g t
ide r
ange
ver
y sm
all.
R
ange
fo
r m
ost
ot
the
coas
t le
ss t
han
one
fo
ot.
Ver
y sm
all.
No
rth
erly
in
win
ter
thro
ug
b
wes
terl
y t
o
sou
ther
ly i
n
sum
mer
. In
win
ter
aver
age
forc
e 4.
So
mew
hat
wea
ker
in s
umm
er.
With
no
rth
erly
and
east
erl
y
win
ds w
aves
m
ay
be
larg
e in
ox
pose
d ba
ys·
and
harbor~.
V/11
1 g
ener
ally
be
ro~J
t!he
r th
an w
est
coas
t.
Hat
er g
ener
ally
cle
ar.
t\J ....
:i.co
TABL
E 2
CO
NT
INU
ED
WES
T C
OAS
T O
F K(
JRE.
A
Riv
er a
nd
sea
ice
suff
icie
nt
to
impe
de
surf
ace
nav
igat
ion
o
ccu
rs n
ort
h o
f nb
out
JSO
t1
in cha~~ela
and
in n
ear
shor
e ar
oo..
EAST
CO
AST
U
F K
ORE
A
So~e
sea
ice
is c
arri
ed
sout
hwar
d b
y w
inds
~,d
curr
ents
. L
oca
lly
pro
duce
d ic
e is
th
in a
nd
pre
sen
t fo
r on
ly s
ho
rt i
nte
rvals
.
So
urc
e:
CIN
CP
AC
FL
T
Inte
rim
E
vla
uati
on
R
ep
ort
1
, v
olu
me
6,
11
22
.
TA
BLI
3
CO
IQ'4
RIS
ON
OP
' JU
NE
WA
RP'A
RE
OPE
RA
TIO
NS
ON
CO
ASt
S O
F IO
RU
WES
T CO
AST
OF K
OREA
El
.ST
COAS
T OF
lO
W
JUne
la
yin
g
Dit
ticu
lt d
ue t
o l
arg
e ti
de
Ro~ine
ran
ge,
at
ron
g t
idal
ou
rren
ta
and
exte
nsi
ve
shoa
l ar
eas
and
num
erou
s ch
anne
ls.
Nat
.u!"
al
Lar
ge d
ue t
o
stro
ng
'U~
Ro~ine
Att
riti
on
cu
rren
ts c
ombi
ned
wit
h b
g
tid
es
and
wav
es.
Det
ecti
on
o!
Gre
ater
lik
elih
oo
d o
! v
isu
al
Rou
tine
J.!
oore
d U
ines
an
d raB~ d
etec
tio
n a
t lo
w
N
tid
e.
Low
tra
nsp
aren
cy w
ill
N
mak
e v
isu
al d
etec
tio
n o
! su
bmer
ged
min
es d
iffi
cu
lt.
Swee
ping
o!
Sat
er b
eca"
.i~e
n
eep
era
can
Rou
tine
Jl
oore
d Kine~
op
erat
e w
ith
rela
tiv
e s
afet
y
at
high
tid
e.
How
ever
dip
of
cin
es i
n s
tro
ng
cu
rren
ts c
ay
lim
it p
orio
do o
f sw
eepi
ng o
r re
qu
ire
deep
dra
gs.
Det
ecti
on
of
Tid
al c
urr
ents
wil
l pr
oduc
e R
outi
ne
Flo
atin
g l
.line
s.
app
aren
tly
err
ati
c m
ovem
ents
.
sou
rce:
CIN
CP
AC
FL
T
Inte
rim
E
valu
ati
on
R
ep
ort
1
, v
olu
me
6,
11
23
.
meant they were capable of intruding upon United Nations naval
operations over a wide area.
In 1949, the Japanese minesweepers were a part of the
Maritime Safety Board (Kaijo Hoancho), which was increased to
8,000 men. That was all that remained of the former Imperial
Japanese Navy (IJN) . Even though the occupation guidelines
demanded the dismantling of the IJN, the Japanese minesweepers
were retained to clear the minefields around the Philippines
and Japan. These ships as well as American LSTs with Japanese
crews, were used in Korea. After the Inchon landing they were
hired under contract. In all, 4 6 Japanese ships and 1, 200
Japanese crewmen served in Korea until the Japanese government
ordered the units home on December 15, 1950, calling their
presence in Korean waters a violation of the Japanese
constitution. Two of the ships were lost, one to a mine and
the other when it ran aground near Kunsan.
The crews were told they would not be used north of the
38th parallel, that they would not conduct combat sweeps but
rather would do check sweeping only, and that they would
receive double pay. All these terms were broken. They were
not given extra pay, and their regular pay was often late.
And they had to make combat sweeps in Wonsan harbor where MS-
14 was lost to a mine. The crews were also nervous about
sweeping for contact mines moored 3 meters below the water's
surface in ships with a 3.2 meter draft. These sweep
operations were illegal according to Article 25 of the Kaijo
23
Hoancho Law. General Douglas MacAurthur dismissed the matter:
"these vessels were hired and employed, not for combat, but
for humanitarian purposes involved in neutralizing infractions
of the accepted rules of warfare." 61
Captain Richard T. Spofford, who had an extensive
background in mine warfare, assumed command of Mine Squadron
3 and Task Group (TG) 95.6, the minesweeping force, in August
1950. 62 He faced a nightmare landscape for a minesweeper. The
currents seized floating mines and carried them down the
Korean coastline in a matter of 15 days; from there they
drifted through the shipping lanes, and often fetched up on
the shores of Japan. 63
Two days after the war broke out, Vice Admiral C. Turner
Joy was appointed Commander Naval Forces Far East. He then
had the needed reservists called to duty. 64 The mine threat
forced the naval gunfire support (NGFS) ships to be recalled
beyond the 100 fathom curve on the east coast. 65 This, of
course, is exactly what the mines were supposed to do.
Task Group 96.5 was ordered to escort ships between
Sasebo and Pusan, to conduct acoustic, magnetic, and moored
sweeps of both ports, their approaches, and the convoy
routes. 66 Later the list of ports was amended to keep pace
with U.N. advances. The task group also assumed control of
the Japanese minesweepers (JMS), and the South Korean
minesweepers (ROKN YMS) .
24
Minesweepers carried out their work either in conjunction
with other minesweepers or in a loose formation. When
steaming in echelon formation the ships held a rigid pattern
so that the lead ship's gear protected the ships following.
A loose formation offered no such protection, but, in night
sweeps especially, echelon formation could be deadly as the
floating mines could not be seen clearly and avoided.
Occasionally ships swept mines alone. If sweeping moored
mines, a line with wire cutters on it was streamed with the
far end attached to a float (kite) and a weight (otter) . As
the gear was pulled along, the wire would catch the mine's
mooring cable, drawing it taught until a cutter hit it,
severed the cable, releasing the mine and revealing it to the
-following destructor boat, whose job it was to destroy the
mines thus located. Magnetic mine sweeping gear was a modified
form of the moored, or "0" (Oropesa), gear. One electrode,
called the short leg, was streamed directly behind the
minesweeper loosely, while a second electrode, the long leg,
was streamed from the stern of the ship to the end of the
sweep wire at the otter and kite. With an electrical
generator on the minesweeper running power down the wires, it
was hoped to generate a magnetic signature similar to that of
a larger class ship for the mine to receive thereby
prematurely triggering its detonator (see Figure 2) .
On July 15, 1950, the minesweepers sailed to P'ohang-
dong, near Pusan (see Figure 3) . Their mission was to clear,
25
Modified moored sweeping gear.
Plan View or ~1ngle 3hip SWoop
...-cutters
Elevation View ot Single ~hip SMeep
~ark 6 la) magnetio awoop l Jig Swoop ).
200 tathom3 ot •o• tno awoep wire
Size '
"0" typo !loa aiz.e 4 with-. 20 roet pendon
""
~Ship
JJ Mark 5 tlagnetio sweep oablo
Short leg eleotrode
---Ship' a oourae
3 rt. or 3 in. sisal line Figure 2. MODIFIED MOORED SWEEPING GEAR AND MAGNETIC
SWEEPING GEAR Source: CINCPACFL'l' Interim Evaluation Heport2, volume 11, 14) ~
-1436. 26
0"1 c 0
z ~
:f
..J
C)
z 0 r
c o,...:w t-u.~
~~~ 0 !a~~ z LLJ d~~ C)
w _J ia~
--~~--...... ..,--....,.rr--t----t----r---'0------~_,.___,..,,....-
SWEPT AREAS Figure 3. P'OHANG-DONG SWEEP
l 0"1 c co .c 0 .. 0..
Source: CINCPACFLT Interim Evaluation Report 3, volume 14, 36
27
in three days, this port situated only 25 miles from the front
lines, to enable the 36 United States ships carrying the First
United States Cavalry Division to unload. The North Koreans,
however, had been unable to mine P' chang-dong as their advance
faltered due to NGFS shelling of enemy troop concentrations
along the Pusan perimeter. 67 Such good fortune would not last
long for the minesweepers.
Assault sweeps and harbor clearance duty placed a heavy
burden on the few available minesweepers. The rest of the
Pacific had been stripped of its mine warfare defenses to
strengthen the Korean force, but it was late October before
these reinforcements arrived in the theater. 68 To boost the
flow of material to the front, Atlantic fleet ships were sent
-to the Pacific. Other ships from the reserve fleet were
activated and made available. Needed equipment was assembled
from American stockpiles and airlifted to Korea. 69
As MacArthur prepared his 5, 000-to-1 gamble at Inchon and
hoped for the best, the planners found further cause for
concern over the landing force's safety when ROKN PC-703,
under Commander Lee Sung Ho, found and destroyed a boat laying
mines just north of Inchon harbor. 70 With the possibility of
mines in the assault area, caution and verification became
critical.
Two months after the unobstructed landing at P' chang-dong
in July, the minesweepers left for Inchon where MacArthur
gambled on a successful landing to outflank the invading NKPA
28
troops, disrupt their flow of supplies flowing through Seoul,
and break the North Korean resistance. 71 Nearly 400 ships
gathered for the assault. 72 Mines, however, still had the
potential to make the operation very costly.
Inchon's tidal range of 33 feet, every inch of which was
needed for the deep draft of the overloaded LSTs to reach the
designated landing beaches, only came on September 15, October
11, and November 3. The current at the entrance to Inchon,
Flying Fish Channel, had a peak ebb and flow velocity of 5
knots. If a ship of the landing force was sunk by a shore
battery or a mine while in the channel, it was possible that
all the ships ahead of it would be trapped in the harbor, and
those behind blocked from entering, thus dividing the assault
force and setting the stage for- disaster. 73 With the muddy
waters and extreme tides, Inchon was a perfect place for
ground mines; this was an assessment in which Vice Admiral
Arthur D. Struble, Commander Seventh Fleet and Commander of
the landing operation, agreed. 74
At 1145 on September 13, 1950, two days before the
assault, as Mansfield (DD-728), the lead ship of the pre
invasion naval gunfire support (NGFS) group, approached Wolmi
do, lookouts spotted 17 Russian contact mines in Pukchangjaso
inlet, below Wolmi-do. DeHaven (DD-727), next in line,
commanded by Commander O.B. Lundgren, a mine warfare expert,
soon confirmed the report. The three lead ships opened fire
with rifles, 20mm, and 40mm guns; destroying the field. The
29
enemy's minefield had not been completed, as they lacked the
necessary parts to assemble the rest of the mines. Commander
Lundgren spotted a pile of the unfinished mines at the base of
the Wolmi-do causeway. 75
Task Group 96.6, which was the initial designation of the
minesweeping force in Korea, was redesignated in August 1950
as Task Group 95. 6, Mine sweeping Force, as a part of the
blockade and escort force for Operation Chromite, the Inchon
assault. 76 One AMS and one AM guided the landing force of 2
LSDs and 36 LSTs with 12 more LSTs trailing them by 6 miles. 77
Once the NGFS ships discovered the mines, the minesweepers had
a far more important mission to perform and so were ordered to
abandon escort of the landing force and proceed at best
possible speed to Inchon. 78
At Inchon, LCVPs and motor launches were fitted out with
minesweeping gear with success. 79 The conversion of LCVPs for
minesweeping had never been tried before; its success
portended safer sweeping of shallow waters that were hazardous
for the larger minesweepers. Henceforth, the use of small
minesweeping boats became a major part of minesweeping
operations in Korea. When the sweepers arrived at Inchon on
September 15, however, nothing was found and so they retired. 80
The few mines had already been taken care of by the bombarding
destroyers. While the destroyers shot mines at low tide, the
landing force passed safely over them at high tide. 81 Thus,
30
although a new minesweeping vessel type had been created, it
could not be tested in a combat sweep with real mines yet.
The minesweepers' presence proved unnecessary at Inchon
due to the North Koreans' failure to sow extensive defensive
minefields. Their next area of operations would, however,
highlight the importance of the sweepers' mission.
Verification of the presence of mines was difficult as
there was no formal plan for reconnaissance; in fact, there
were no plans at all. Local initiatives were begun. Single
planes roamed the harbors and coasts searching visually for
any signs of mines. They flew at 500 to 1,000 feet above the
sea with every hatch manned. Most sightings occurred at 1 to
3 miles, although once an APS15 radar equipped aircraft
detected a mine a 5.5 miles. 82 Reconnaissance was of little
help in the last week of September. Four ships were damaged
and one was sunk. When the minesweeper Magpie (AMS-25) sank,
a helicopter searched the area looking for survivors. Instead
they found a pair of mines off Kokoko. This heavy reliance on
aerial searches, dictated by the broad expanse of minable
waters and the presence of floating mines, became the hallmark
of Korean minesweeping operations. 83
The North Korean sown mines very quickly drew blood from
the United Nations forces. The war came home to the navy when
in the course of a week five ships were either sunk or badly
damaged. From September until November, mines claimed 13
ships as casualties compared to five damaged by bombs and
31
shore battery fire. Of the 13 ships, four ships struck mines
in waters below the 38th parallel (see Figure 4) . 84
The destroyer Brush (DD-745) was the first victim. While
steaming off Tanchon, 1,000 yards astern of the destroyer
Maddox (DD-731), seeking shore batteries to destroy, Brush hit
a mine which tore a five-foot hole in her side. Thirteen men
died ~n the explosion and 34 were seriously injured.
Commander Fletcher L. Sheffield, the ship's captain,
"remembered that the destroyer Meredith (DD-726), a ship of
the same class similarly damaged during the Normandy assault
in 1944, was lost before she could navigate the English
Channel. " 85 The nearest safe port was Sasebo, Japan, over 470
miles away. Escorted by the cruiser Worcester (CL-144), the
destroyer DeHaven (DD-727), and the salvage tug Bolster, Brush
made it to port on September 30, four days after the
explosion.
On September 30, in the North Korean harbor of Chosen, 60
miles north of the 38th parallel, the destroyers Lyman K.
Swenson (DD-729) and Mansfield (DD-728) searched for a downed
B-26 pilot. While Swenson stood out at the 50 fathom curve,
Mansfield went in. Having just heard of the fate of the
Brush, one sailor offered odds on whether they also would hit
a mine and was taking bets when the sea and Mansfield's bow
erupted. The explosion tore a hole in the bow of the ship
erasing the numbers 2 and 8 leaving the 7 behind. As Seaman
Glendon Glass put it, "I can't say that it made me feel any
32
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33
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killed. Mansfield made it back to port without any further
incidents.
The wooden-hulled auxiliary minesweeper Magpie hit a mine
shortly after arriving from Guam for her Korean tour. On
October 1, 1950, while sweeping a patrol channel in company
with Merganser (AMS-26) two miles off Chuksan, 30 miles North
of P'ohang-dong, Magpie hit a floating mine that slipped past
the sweep gear. Twelve men of the crew of 33 survived, all of
them injured.
On the same day, near Mokpo, ROKN YMS-504 hit a mine with
her starboard propeller causing the sympathetic explosion of
two nearby mines.
were
With her hull leaking and the engines
lucky they had suffered only five ruined, they
casual ties. 87 Unfazed, the captain "radioed that he would
'soon be ready again to kill more Reds.' " 88 Her sister ship,
which had hit a mine on September 28, fared much better. ROKN
YMS-509 hit a mine along the south coast, demolishing the bow
but not harming the crew or the engines. As a result, the
ship made it to the ROK naval base at Chinhae. 89
These heavy losses in such a short time shocked the
Commander, Naval Forces Far East (COMNAVFE) , who promptly
ordered the east coast NGFS ships outside the 100 fathom
curve. By doing so, the ships were removed from danger, but
they were also removed from effective gunfire support range,
35
which diminished their effectiveness and thus helped the North
Koreans. 90
Both Captain Spofford and Admiral Joy pressed repeatedly
for an acceleration of the activation of reserve minesweepers.
But as other ships, especially destroyers, were in more demand
than minesweepers, their efforts met with little success until
U.N. losses began to mount. All of the vessels lost were
destroyer size or smaller. 91
Soon after the Inchon landing, the Canadian Tribal class
destroyer Athabaskan (DDE-219) created a new minesweeping
method. The reason for this was that there were no
minesweepers or minesweeping gear available to clear Kunsan
harbor for them. The plan called for a few men to go into the
harbor 1n one of the ships' launches at low tide when the mine
would be exposed. They would locate each mine, attach a
demolition charge with a five minute timer to the mine, and
row as fast as possible to get clear of the explosion. In
this manner the Athabaskan's crew destroyed five mines. 92
The clearance of Kunsan by minesweepers came on October
2-3, 1950, with a check clearance from October 21 to November
2, 1950. Pledge (AM-277), Mocking Bird (AMS-27), Chatterer
(AMS-40), Kite (AMS-22), and Redhead (AMS-34) cleared a 1,500
yard wide, 22 mile long channel. A total of 49 M26 mines were
reported. Seven of the mines were swept and destroyed (see
Figure 5) . 93
36
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CHAPTER III
FORMING OF A NEW STRATEGY
The United Nations forces' Inchon landing threatened the
North Korean supply lines, which ran through Seoul. The enemy
had little choice but to withdraw from the Pusan Perimeter and
attempt to regroup beyond the South Korean capital. On
September 29, 1950, while in newly liberated Seoul, General
Douglas MacArthur ordered his commanders to prepare for
another amphibious assault, designated Operation Tailboard,
which he felt would end the war. 94 The hammer was to fall on
North Korea's principal port, the east coast city of Wonsan.
In addition to the port facilities, Wonsan was a
transportation center in North Korea second only to the
capitol, Pyongyang. The major rail line from the Soviet Union
ran along the coast into the city; highways emanated from the
port to the major Korean cities, even Seoul.
MacArthur set the landing date at October 20, which left
three weeks to plan the assault. Adding to the headache of
planning a corps-sized assault landing, the Wonsan area was
known to be mined. Although extensive minefields were not
expected at Wonsan, Vice Admiral Arthur D. Struble, Commander
Seventh Fleet, warned the ships headed for the port anyway. 95
The army and navy disagreed on how the Wonsan assault
should be executed. The argument was unique in that neither
force wanted to use the mode of transportation they normally
38
favored. The army, impressed by the effectiveness of the
Inchon landing, desired another amphibious landing. The navy,
on the other hand, wished the army would go overland. One
reason was that the sea trip to Wonsan from Inchon was 830
miles, much longer than the approximately 110 mile overland
route. The army countered that if the X Corps went overland
through the mountains half of their heavy equipment would be
lost.
Another problem encountered in the planning stage was
that outloading the troops from Inchon would hinder the flow
of needed supplies to the Eighth Army, which depended upon the
same port facilities. A shortage of shipping, amphibious
craft, and minesweepers further complicated the situation.
Despite these problems, the army pressed to go by sea. As a
result, and as a precaution against the possibility of mines
at Wonsan, Vice Admiral Struble, on October 2, ordered all
available minesweepers to get underway for Wonsan
immediately. 96
Struble planned on clearing the harbor in five days. If
weather was bad, or if influence mines were found, it might
take longer. On October 6 he advanced the date for
commencement of sweeping the harbor to ten days before the
landing was to take place. 97
A few days into the operation MacArthur had second
thoughts about the landing. In view of the difficulties the
navy was encountering clearing the harbor and the fact that
39
the ROK Army was sweeping up from the south, MacArthur was
considering shifting the objective of the planned landing
north to Hungnam. Vice Admiral C. Turner Joy, Commander,
Naval Forces Far East, refused to alter the plans as there
was insufficient time to plan the landing and it would divide
and diminish the effectiveness of the minesweeping force,
which was barely adequate to sweep one harbor. 98
What the United Nations planning staff could not predict
was the sheer size of the mine problem that awaited them at
Wonsan. Intelligence was slow to recognize the North Korean
mining activity. The Wonsan minefield covered almost 400
square miles. Composed mostly of 1904 vintage Russian contact
mines, the field was seeded with magnetic influence mines
"sensitive enough to react to the wooden-ship's engines,
making minesweeping by the surface vessels deadly. " 99
The operation was a tragedy waiting to happen. "At
Okinawa, for instance, we used 100 sweepers, at Normandy we
used 300. At Wonsan we started with 10. "100 Such a force was
inadequate for the task at hand, and therefore was very
quickly reinforced. Admiral Joy received the two AMs from
Japan that had been in reserve, one AMS from Guam, and two
DMSs from the west coast.They were immediately assigned to the
Wonsan operation along with the high speed transport Diachenko
(APD-213), the repair ship Kermit Roosevelt, and eight
Japanese contract sweepers. In time, four U.N. frigates and
some ROKN YMSs also joined in.
40
Help was also available offshore from the commander of
the NGFS ships, Rear Admiral John M. Higgin's, flagship, the
cruiser Rochester (CA-124), and several destroyers provided
gunfire support. Rochester's helicopter and PBMs operating
from the tender Gardiners Bay provided a mine searching force,
while aircraft from two fast carriers were available for
assistance.
Clearing a path from the 100 fathom curve to the assault
beaches at Kalma Pando required the sweeping of an
approximately 30 mile long channel and 50 square miles of the
harbor in advance of the landing force. 101 Selecting the route
had been difficult. Six miles from the assault beaches lay
the island of Yo Do, which could be passed to the north or -
south; realizing that the Soviets had used the northern
channel for their shipping, it was decided to make a direct
run south of Yo Do to the beaches (see Figure 6) .
To help accomplish the task three ROKN YMSs and eight
Japanese minesweepers, which arrived on October 8 with their
commander, Captain Tamura, joined the struggle. On October
10, the first day of the sweeping, Incredible, Chatterer,
Osprey, Pledge, and Mocking Bird swept 18 mines up to the 30
fathom curve . 102 Dan buoys were placed to mark the swept
channel as the sweep progressed. 103 Rochester's helicopter
aided the force, searching out mines ahead of the sweepers. 104
On the October 10 sweep to the 30 fathom curve, the 28
mile channel cut into a heavily mined area clearing the 18
41
..... Figure 6. WONSAN APPROACHES
42
• --~-·------·----------
~~ C...••~.-K-
~ · ·~· · • ..... ·-~ . =.;:·..:=~ _......,. "'- • " .. ·-· . ·~ ·~ ............. , ... '-......... . ,...., ............. ,-.. .,. ·-.~. ,, .. ,.,. ..... _,... ·-~· . ._...__ ·- ....., .. ~· ·~·
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Figure 6. CONTINUED
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Source: CINCPACFLT Interim Evaluation Report 1, volume 6, 11 36 .
43
mines swept that day. The first warning of the danger came
from the helicopter pilot, B.D. Pennington, who spotted five
lines of mines inside the 30 fathom curve . 105 When the new
mine lines were detected, the ships retired. 106 As a result,
the sweep plans were changed to go through the Russian
Hydropac channel, passing between Yo Do and Hwangt' o-do
islands. This meant clearing a 34 mile channel, 24 miles from
the 100 fathom curve to the outer islands, and 10 miles of
inner harbor. 107
On October 11, Underwater Demolition Team (UDT) personnel
from Diachenko went out in small boats to help search for
mines ahead of the minesweepers. 108 They also searched Yo Do
and Ko-to islands for controlled minefields, while overhead a
PBM searched for mines, communicating sightings to the units
below. The ships swept around Yo Do and turned toward Kalma
Pando. Pirate led the sweep followed by Pledge and
Incredible. Ahead of them was their helicopter spotter who
could communicate with the minesweepers through the DMS
Endicott. At 1122 they entered unswept water. 109 Kite and
Redhead followed the group marking the channel with dan buoys.
In all, 16 mines were cut, one of which got stuck in Pirate's
f d . 1 110 sweep gear and was taken out to sea or ~sposa .
The urgency to complete the minesweeping operation was
removed as Brigadier General Kim Baik Yil's ROK I Corps, whose
advance had earlier been slowed by heavy NKPA resistance,
seized the city on October 11 while the 1st Marine Division
44
remained embarked in navy amphibious force ships at sea,
unable to land until the mine threat was neutralized. 111 The
fall of the city removed the threat of shore battery fire,
simplifying somewhat the navy's work. 112 Until that time the
minesweepers had, of necessity, operated in company with a
gunfire support ship.
Disaster befell the minesweeping force on October 12. The
same sweep formation as the day before was used with the AMs
in lead and the AMSs danning, and Endicott on hand for gunfire
support. As the ships swept around Yo Do many mines were cut.
At noon the helicopter spotter reported, and Pirate's sonar
confirmed, three mine lines ahead. 113 Moving at eight knots,
the ships passed between Yo Do and Ko-to sweeping 12 to 16
m~nes. The helicopter spotter reported the mine lines
extending between Yo Do and Ko-to, as well as near Sindo, but
gave no precise position or depth. Upon completion of the
sweep, the ships moved near Sindo to retire as planned. There
they encountered unanticipated trouble:
About 1208, U.S.S. Pirate (AM-275) had many sonar contacts ahead. Pirate changed course to 245 degrees true to avoid the nearest contact. Almost immediately a shallow mine was sighted close aboard the starboard bow and evasive action was taken. At 1209 Pirate struck a mine and began to sink astern. Due to loss of power, attempts to contact the other minesweepers were to no avail. U.S.S. Pledge (AM-277) and U.S.S. Incredible (AM-249) immediately launched their boats and sent them to the rescue of survivors. At about 1210 enemy shore batteries on Sindo island commenced shelling Pirate and her survivors. Also about this time Pirate commenced abandoning ship. At about 1213 Pirate capsized and sank, leaving about 43 feet of the keel forward showing with her stern apparently resting on the bottom.
When the Pirate was mined she stopped dead in the water. The Pledge, therefore, was forced to alter course to the left
45
in order to avoid becoming fouled in the Pirate's rninesweeping gear.
Enemy shore battery fire was immediately and effectively returned by the Pledge, Incredible, Redhead, and Endicott. Friendly air units gave further assistance.
About 1215, Pledge, while in the act of changing course to port struck a mine. Boats from the u.S. S. Diachenko (APD-213), Endicott (DMS-35), and Doyle (DMS-34) immediately carne to the assistance of the survivors. Pledge sank in about 45 minutes. 114
The area was scoured for survivors by small boats,
helicopter, PB4 Y, and UDT personnel from Diachenko. Of
Pirate's crew of 77, six men were missing and 43 were injured.
Pledge's crew roster of 74, short two men who were not aboard
at the time of the disaster, was reduced by six men, who were
missing, and 41 injured. Two visiting Japanese aboard were
uninjured. 115 With Admiral Joy's permission, Rear Admiral
Allen E. Smith, the commander of the amphibious task force,
starkly summarized the situation for Chief of Naval
Operations, Admiral Sherman: "We have lost control of the seas
to a nation without a Navy, using pre-World War I weapons,
laid by vessels that were utilized at the time of the birth of
Christ. " 116
One reason for the losses was that on tight turns away
from the sweep gear the kite and float broached the surface
making them useless until recovered. As a result, tests were
run on the Mocking Bird using a depressor to hold the sweep
wire below the surface and prevent the gear from broaching.
After a few successful tests the other minesweepers were
outfitted with the gear. Faster and tighter turns were made
until finally the ships made turns at maximum speed with hard
46
rudder . 117 The tests were successful. Only one other United
States minesweeper was lost during the war, and that loss was
no fault of the new sweeping gear.
For the next two days emphasis shifted to searching for
the mines. Patrol planes and helicopters searched for and
destroyed mines by strafing. UDT personnel also boarded small
boats and buoyed mines detected by helicopter and the location
of gaps in a mine line where the sweepers could safely pass. 118
Minesweeping boats capable of moving at four knots close
inshore in 15 fathoms of water were also used. This group was
composed of one 40 foot launch, one landing craft vehicle-
personnel (LCVP), and one landing craft mechanized (LCM) . 119
In an attempt to prove the feasibility of aerial .
countermining, which had been attempted unsuccessfully in
World War II, 31 ADs (Skyraiders) and 16 F4Us (Cosairs) took
off from the carriers Philippine Sea and Leyte on October 12
in an attempt to bomb two five mile strips of water placing
the bombs 200 feet apart. The Skyraiders carried three 1,000
pound bombs fused to detonate 25 feet underwater, while the
Corsairs carried one 1,000 pound bomb each. The right column
was bombed by 14 ADs and 8 F4Us, the left column by 17 ADs,
with 8 F4Us remaining in reserve. Flying at 180 knots at
1,500 feet, they were guided to the drop zone by the ships and
search planes which had marked the lines. About 109 1, 000
pound bombs were dropped, but the results proved inconclusive,
47
as it could not be determined if the bombs detonated any
mines .12o
A major innovation in the Korean War was the use of
patrol aircraft and helicopters to locate and destroy mines.
Beginning on September 29, 1950, Commander, Fleet Air Wing
Japan (COMFAIRJAP) provided Mariner and Sunderland aircraft
from Patrol Squadrons 42 and 47, RAF Sunderland Squadron 88,
and later RAF Sunderland Squadron 205 based at Iwakuni, Japan.
On October 6, patrols of both coasts of Korea began with the
aircraft flying from Chinhae, Korea. At Wonsan aircraft
discovered and charted 175 mines, detonating five mines and
sinking six others with .50 calibre machinegun fire. They
carried overlays of the hydrographic charts used by the
sweepers, marked the locations of the mines they spotted, and
dropped the charts to the waiting sweepers below . 121
With the UDT frogmen, minesweeping boats, helicopters,
and PBMs hunting for mines, the search quickly developed into
a competition between the groups to run up their score of
mines found. Some crews even ignored fire from the shore
batteries in their quest. The search created so much interest
among the watching North Korean fishermen that they joined the
hunt. One old man kept yelling and gesturing at the water.
When Lieutenant Commander Don DeForest, Captain Spofford's
assistant recently transferred from MINELANT, investigated, he
discovered that the man had spotted a mine. He rewarded the
fellow with a pack of cigarettes and designated him Ko-to
48
Float 1, as Ko-to was the man's horne. Two more boats soon
joined in. By nightfall DeForest realized that Ko-to Float 1
was too far out to get horne in the rising seas, so in order to
avoid possibly firing on the boat in the night by mistake they
towed him horne. The old man apparently reported his treatment
by the Americans to the 200 refugees and villagers living on
Ko-to, for the next morning four more fishing boats joined the
search. In return the Americans sent as much food as could be
spared and a doctor to help the sick and injured. The seven
North Korean boats proved useful in the hunt.
DeForest's adventures were not over yet, though. The
next day, while in the bow of an LCVP hunting mines, he
watched as a mine popped to the surface less than two feet -
from his position. Even as he gave the order to back down the
boat struck the mine right below his perch. Amazingly,
nothing happened. The LCVP had apparently missed all five
horns, contact with any one of which would have destroyed the
boat. 122 As he later put it, "I'll never forget the Russian
serial on that mine-the numbered part of it that I could read.
I'll remember it after I have forgotten my name. It was number
11825-11825--that will stick with me forever. " 123
By October 23, 16 mines had been discovered by helicopter
searches in the line that sank the Pirate and Pledge, alone . 124
More mines had been found elsewhere in the harbor as well.
Such progress notwithstanding, the sweeping was taking too
long. As a result, on October 21, one day after the landing
49
had originally been scheduled, General Almond requested
that the Marines be offloaded at Kojo, 39 miles south of
Wonsan, where Japanese and ROKN LSTs had run through unswept
waters. Admiral Doyle rejected the request as it would have
split the landing force and so the sweeping continued at
Wonsan . 125
Don DeForest, meanwhile, borrowed an LCVP to cross the
unswept waters of Wonsan harbor, where he picked up a jeep and
an interpreter-bodyguard from the ROK Army. Searching along
the waterfront, he located some fishermen who told him that
the mining personnel had been kidnapped or shot and that the
mine depot was about 25 miles north of the city. They could
not say for certain where it was since it had been heavily
guarded.
Leaving the city he travelled along a sniper infested
dirt road. Fifteen miles from Wonsan he carne to a village of
about 1,000 people. Everyone but a five year old girl ran for
cover at his approach. "'It seems incredible that my success
or failure rested in the hands of this little girl,' DeForest
said. 'But it did. She was my only liaison. Why she remained
behind I'll never know because I was worse than a stranger.
I was a foreigner!' " 126
He managed to lure her over with a chocolate bar which
soon brought out the other children and their mothers, who
followed cautiously. He was soon motioned into a white wooden
house where he met the village elder. After he considered
50
DeForest's request for assistance he agreed to cooperate
despite the possibility of Communist retribution.
The elder provided him a guide who also knew one of the
sampan skippers who planted some of the mines and a North
Korean official who went out in the junks. The guide took him
farther into the countryside to where the mines had been
assembled. He was shown the bunker where the magnetic mines
were assembled and where the North Koreans who had helped in
the project had been killed. Thirty Russians had been in town
until October 4. When the mines were laid, the Soviets were
on the ships. If a mine was laid out of place the pilot was
shot and another man was promoted to replace him. Few
mistakes were made twice.
Having found nothing, DeForest began drawing the diagram
of a magnetic mine. When he finished, his guide led him to a
pile of straw. It took no time at all to find what he was
looking for. On the first try he came up with the search coil
for an 1,800 pound mine. Deforest made it back to Wonsan
without difficulty. He then found the skipper and the other
man, who had worked in the hydrographic office. Both men
suddenly became very cooperative after they learned the secret
of the magnetic mines was out. The skipper had barely managed
to make it out of enemy hands. He knew so much that the
Russians decided to take him and four other men back to
Vladivostok. The skipper slid over the end of the PT boat as
it left Wonsan . 127
51
Intelligence turned up shipping manifests. According to
the documents, 4,000 mines had been shipped through Wonsan
between July 10-20. 128 The Soviets set up a mine school for
MKB and M26 mines for 18 men. Soldiers laid the mines off of
sampans towed by junks in the middle of the night. They were
rolled off the end of the boats at 1-1.5 minute intervals.
This way 3, 000 mines had been laid in a period of three
weeks. 129
Later the United Nations forces discovered that the
Soviets had provided the North Koreans with torpedoes and
depth charges. On October 16, fourteen twenty-four foot long
torpedoes, as well as 29 300 pound and 40 fifty pound depth
charges, were found in a tunnel near the Wonsan airfield.
With this arsenal were 167 contact mines. U.N. forces found
over 600 mines ashore at Wonsan after the city fell. 130
Nevertheless, losses continued to mount in the Wonsan
minefields. On October 18, the ROKN LST BM SF-673 struck a
mine in the outer harbor when it tried to take a short cut to
the beach through an unswept area.
and continued on to the shore . 131
It reported minor damage
The day before, the Japanese minesweeper MS-14 had struck
a mine and sank off the southern shore of Yo Do island. 132
MacArthur ordered a blackout on the news of the sinking, or
even of Japanese involvement in the war, due to the
information's propaganda value to the enemy . 133 The loss of
that ship infuriated the Japanese crews, who had been promised
52
double pay, that they would not sweep above the 38th parallel,
and that they would not do any combat sweeps. All the
promises had been broken. They especially felt used as they
were asked to sweep mines at a depth of 3 meters with ships
having a draft of 3. 2 meters. As a result, three of the
minesweepers left the next day and were dismissed from the
minesweeping force. Although the crews of the Japanese ships
had been well supplied and repaired by the American Navy, even
their reports indicated the troubles they suffered working
with the Americans. Among those troubles were language
difficulties, a lack of communication equipment to work with
the observing ship reduced them to visual signals only, and
generally the inability to coordinate with the American
mine sweeping effort. 134 De.spi te these difficulties, they still
managed to do a good job.
Another ship was lost on October 19. While sweeping the
moored mine line between Tae Do and Hwangt'o Do, the third
ship in the formation accidentally triggered an influence mine
with its kite and float. The explosion triggered a second
explosion 150 yards south of the first one. At that all the
ships stopped their machinery, cut their gear, and headed out
at one-third speed on one engine. The ships made it away
safely but, due to poor communications, they could not warn
a formation of ROKN ships headed right for the mine fields. 135
Commander Sihak Hyun had wanted YMS-516 in the lead of
the formation to be followed by his flagship, PC-704, YMS-510
53
~n third place, and the six power boats on hand to bring up
the rear. After repeated orders for YMS-516 to proceed 40
without any action taken by that vessel, he began to worry.
The other captain, Lieutenant Commander Jun Churl Ung, had
been his classmate at the Chinhae Naval Academy. Hyun knew
the loss of a minesweeper would cause him to lose face but he
couldn't risk the valuable PC, which, in the diminished scale
of the fledgling ROKN, they thought of as a cruiser. Hyun was
forced to take the lead as his friend refused to obey his
orders. A powerboat took second place and YMS-516 the third
position. Moving at one-third speed on one engine, Hyun saw
the explosions set off by the American minesweepers. Two
minutes later, he felt another explosion. YMS-516, whose
commander had refused to perform his duty for fear of risking
his ship, most ironically had struck a mine and was sinking.
Four men were killed instantly and 13 men were missing. 136
Over a year later, on December 26, 1951, Commander Hyun's
humiliation over losing YMS-516 was compounded when his ship,
PC-704, struck a mine off Yo Do island and sank with all
hands.
Wonsan harbor's mines claimed another victim on November
16, 1950. Army tug LT-236 was towing a crane barge when it
struck a mine at the entrance to the harbor. Its sinking
marked the greatest loss of life yet, 30 of the 40 crew aboard
died . 137 The harbor minefield had claimed five ships and
injured one other.
54
On October 25, after fifteen days of work by a motley
crew, a channel into the assault beaches at Wonsan was
declared clear. 138 The enemy minefields had delayed the
landing of the amphibious force since October 19, when the 7th
division arrived off Wonsan. Forced to back and fill while
the minesweepers went about their dangerous mission, the
amphibious force first sailed south for twelve hours then
north arriving back off the port only to be ordered to head
south again. Dubbed Operation Yo-Yo by the men aboard the
ships, problems almost as serious as mines arose. Food ran
short and dysentery flared up on the MSTS transport Phoenix
affecting 700 of the 2,000 men aboard. After six days, from
October 19 to October 25, at sea outside, the wait was over as .
the assault ships descended upon the beaches at 1500 hours,
October 25 (see Figure 7) . 139
The landing proved anti-climactic. Fifty-thousand men
hit the beaches only to be welcomed by banners set up by the
ROK troops who had liberated the town over a week before.
Another sign, this one set up by Mine Squadron 3, let the
Marines know who had cleared the beach for them. Perhaps more
humiliating for the ever proud Marines was that Army Major
General Edward M. Almond and Comedian Bob Hope, who was in
town performing with his USO group, were on hand to welcome
them ashore . 140
Nine days after the capture of Wonsan, the North Korean
capital of Pyongyang fell to United States and ROK forces
55
rOiffiHIINfi-MAN
Figure 7. WONSAN
~
(Kat-to) ;w ...
GR IDIRON
11!111 •-o-.-....., ....... _ ·<!l· c:a.r.-· ....,._ •• , ,___.. ~ .. <11· ~"- 100
""""" -- ~ -· .,_.. . ....... DO
Source: Cagle and Manson, The Sea War in Korea, 601.
56
advancing north along Korea' s west coast . The supplies
flowing into Inchon for this front were too far from the
combat zone. The increasing distance from the front and the
relatively small capacity of the Inchon port facilities made
it obvious to United Nations commanders that a new port,
nearer the front lines, was needed. Attention focused on the
next significant port in North Korea, Chinnampo.
Admiral Joy obtained the services of Commander Donald
Clay and Mine Force Atlantic Fleet's Commander Stephen Archer.
He placed Clay in charge of intelligence in Chinnampo and
sent Archer off to Sasebo to commandeer any ships he could. 141
Commander Archer's experience in mine warfare was
. . ~mpress~ve. He had been an observer on a British minelayer
from 1940 to 1941. From June, 1941, until April, 1943, he
attended the Mine Disposal School at the Washington Navy Yard.
In July, 1950, he commanded Mine Division 4. On October 4,
1950, he reported for duty in Korea as the head of the
underwater reconnaissance effort at Wonsan. 142
Archer had to scrape together a force to sweep Chinnampo.
This was a challenging assignment, as there were no ships,
men, or plans available. 143 Among his first "volunteers" were
the destroyer Forrest Royal (DD-872), DMSs Thompson (DMS-38)
and Carmick (DMS-33), AMSs Pelican (AMS-32), Gull (AMS-16),
and Swallow (AMS-36) out of Pearl Harbor, ROKN YMSs 502, 306,
513, and 503, a helicopter, SCAJAP LST Q007 to give the
helicopter a place to land, Horace A. Bass (APD-124) with UDT
57
One, Catamount (LSD-1 7) with 14 minesweeping boats, and
Bolster (ARS-38) Later he received 13 Japanese minesweepers
with their own mother ship and the Japanese guinea pig ship
Soei-Maru (SS/MV-32) .
Mine clearing operations began on October 29 when
Thompson and Carmick started sweeping in the Yellow Sea, 39
miles from the area in which mines were expected. Most of the
ships arrived for duty by November 2, with the exception of
Catamount which arrived three days later with her LCVPs rigged
for moored and magnetic sweeping . 144
Acting on hard lessons learned at Wonsan, the Eighth Army
was ordered to seize all ship logs, hydrographic charts, mine
plans, boat captains, and minelaying personnel in Chinnampo.
Unlike Wonsan, the water in Chinnampo was shallow, muddy, and
fast. The tidal range was 12 feet and a five knot current
prevailed during ebb and flow. There were two channels
approaching the port. The southern channel was a mere 15 feet
deep at high tide while the other one was twice that (see
Figure 8) . 145
Chinnampo was chosen for opening because of its location
along the Taedong estuary near Pyongyang, similar to Inchon in
relation Seoul. Mud banks line the shores and islands dot the
approach. After Wonsan was opened, the PBMs shifted back to
hunting along the west coast. Three days searching garnered
34 mine sightings and 16 mines sunk by strafing. 146
58
Figure 8. CHINNAMPO SWEEP Source: Karig et al. ,354.
59
THE CHINNAMPO
SWEEP Oct 29th to Nov 20th 1950
Minehunting preceded the sweepers. PBM and helicopter
patrols and surface searches by rninesweeping boats and the UDT
personnel helped clear the way into the harbor. An LST was
used to good effect as a helicopter base and a supply depot
for the force. The operation needed all the help it could get
as it sought to clear 200 square miles of water between them
and the port. 147
As the entire Yellow Sea is minable, the sweep began 39
miles from the channel entrance, which put them 69 miles from
the port. Commander Clay and Lieutenant (junior grade) Hong,
ROKN, discovered the details of the minefield. The information
carne from a North Korean river pilot called simply "Shorty,"
who had helped lay the mines and knew the location of them
all. The field consisted of 217 moored and 25 magnetic mines
placed in five lines north of Sok-to and one line to the south
of it. Searching before they swept an area, the minesweepers
and MSBs maneuvered to avoid the mines rather than actually
sweeping them. As the minesweepers were few in number and
late in arriving, the task of clearing the channels fell to
the MSBs. In addition, Martin Mariners with the seaplane
tender Gardiners Bay began working after October 2 8. RAF
Sunderlands joined shortly afterward. In six weeks the patrol
planes accounted for 340 mine sightings alone . 148 By November
3 the shallow southern channel was opened to small ships and
the minesweepers turned to the deeper channel, which would be
needed to get the larger LSTs through (see Figure 9) . 149
60
SECRET
CHINNANPO APPROAC ES
HUIIL( IUIIll
Figure 9. CHINNAMPO APPROACHES
61
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Figure 9. CONTINUED SWEPT AREAS Source: CINCPACFLT Interim Evaluation Report 3, volume 14, 42.
Winter proved a dangerous enemy of the minesweepers, for
it brought heavy seas and chilling conditions that reduced the
effectiveness of mine sweeping crews working in open
mine sweeping boats. The MSBs, themselves, had difficulties in
the mid-winter operation as their engines needed to be thawed
every morning. Similarly, the helicopter crew removed the
lube-oil from the helicopter every night to keep it warm.
The weather also affected the mines. Four mines broke
their moorings in rough seas over a 24 hour period. This
presented another danger to the ships as the floating mines
could drift right into their anchorages. The minesweepers,
therefore, had to remain alert for the floaters.
Four of the LCVPs were rigged for moored minesweeping and
another four for magnetic sweeping . 150 Two 40 foot launches
from the carrier Boxer had also been fitted with minesweeping
gear as MSBs. The effort proved a total failure at Chinnampo,
however, as the fast current quickly burned out the boats'
engines when the gear was streamed. 151
Planes from the British carrier Theseus sank a barge in
the Chinnampo area believed to be laying mines. Later the
sunken barge was found with 15 mines still aboard. 152 Those
mines, at least, never troubled anyone. Theseus also provided
fighter cover to protect the minesweeping operation from
harassing aerial interference as well as shore batteries. 153
In the meantime Catamount was used as a mine school for ROKN
63
officers and men. Six full crews were trained for Korean
minesweepers being fitted out at Sasebo, Japan.
From October 29 to December 3, 1950, eighty mines had
been cleared at Chinnampo, 36 by PBMs, 27 by UDT frogmen, 12
by storms, and five by the minesweepers . 154 In addition to the
8 0 M-2 6 mines swept, 4 magnetic mines were destroyed (see
Figure 10) . 155
The day Wonsan was opened, October 25, 1950, Chinese
troops engaged ROK II Corps troops at Unsan, near Sinanju.
Four days later, ROK I Corps attacked enemy positions near the
Changjin (Chosin) Reservoir.
With the nearest supply point on the east coast at
Wonsan, and that still being cleared, the need to open Hungnam
became paramount (see Figure 11) . From there United Nations
troops could be better supplied for the drive to the Yalu
River.
Fortunately, naval intelligence paid off. Kim Tae Lee,
the captain of the lead ship during the mining operations at
Hungnam, was located and proved more than willing to
cooperate. Kim had helped plant two lines of mines: the inner
line was laid by two ships carrying 18 mines each, while the
outer line was laid by three ships, two carrying 18 mines and
one carrying 20. The minefield thus numbered 92 mines. Kim
was uncertain whether magnetic mines had been laid. He
informed the intelligence officer of how he and the Russian
navigator had laid the mines, and he volunteered to pilot
64
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Figure 11. HUNGNAM
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source: CINCPACFLT Interim Evaluation Report 1, volume 6 , 114 0 .
67
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Figure 11. CONTINUED
~ • •·41 H-. _.,._ .J>...-l I ~ -·· ~ •• 1/..1 ,_,_
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68
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.SECRET
.-ol.n ~· tAY' .,...._.,.. ••
~r·.,.-.
United Nations ships in the area . 156 From November 6 to
November 11, Doyle (DMS-34) and seven AMSs cleared a 28 mile
long, 1600 yard wide channel. 157
The opening of the port was very important as the Chinese
"volunteers" stepped up their attacks. The day the sweep
began, United Nations troops held off assaults along the
Ch'ongch'ong bridgehead near Sinanju after the loss of Unsan.
Marines from Wonsan relieved the ROK troops fighting around
the Changj in Reservoir on November 2. The U.N. advance in the
face of heavy resistance was slow. By November 26 the Marines
were nearing the southern end of the reservoir itself. The
next day, as U.N. troops advanced on Samsu, near the Yalu
River, 100,000 Chinese troops descended upon the Marines.
Fortunately, Hungnam provided a nearby logistical base for
operations.
The overwhelming power of the Chinese formations began to
take its toll, however, and the Marines began a gradual
fighting withdrawal on December 2, 1950. The naval gunfire
support ships in Hungnam harbor provided supporting fire to
the Marines around Hungnam. By December 10 the Marines had
completed their epic withdrawal from "frozen Chosin" to
Hungnam where they were protected from enemy attack by the
NGFS ships' barrages. They then were loaded on board
transports and redeployed to Pusan. In two weeks 200,000 men,
350,000 tons of equipment, and 17,500 vehicles were shipped
from Hungnam, while the enemy was kept at bay by intense and
69
accurate naval gunfire. Unlike retreating army units, which
tended to leave equipment that proved difficult to move, the
Marines took everything with them, even the airlifted bridge
they used to cross into Hungnam.
While these units left Hungnam, troops were outloaded
from Wonsan beginning December 3. For the next week the
troops were shipped from the port to Pusan. On December 5,
troopships entered Chinnampo to begin evacuating the men to
Inchon and Pusan. That same day troops began to withdraw from
Inchon. 158 Under the intense pressure of the massive Chinese
Communist intervention, the United Nations withdrew southward
rapidly. This development had the effect of overextending the
advancing Communist forces' supply lines.
In March, 1951, U.N. forces launched Operation Ripper, a
counterattack against the weakened North Korean and Chinese
troops. With their lengthy supply lines under air attack by
United Nations forces, the enemy slowly started to fall back.
By the end of the month, Seoul and Inchon had been retaken.
The front stabilized after July, 1951, when Chinese resistance
stiffened. The new line would be held with only minor changes
until the end of the war . 159
Rear Admiral John M. Higgins was appointed Commander of
the newly activated Mine sweeping Force Western Pacific on
November 11, 1951 . 160 The mission of this force was to make
check sweeps of Wonsan, Hungnam, Songjin, the coastal area
from Songjin to Kosong, the area from Sok-to to the Han
70
estuary, Cho-Do, Sok-to, and Haeju, all of which were in enemy
hands. In all, this totalled 270 square miles of harbors and
300 miles of coastal channels to be kept clear. These fire
support, bombardment, and patrol channels were kept open by an
on-paper force of 6 AM and 14 AMS of which only half could be
effectively maintained on station. 161 Routine patrol and the
blockade of the Korean coast constituted the major naval
activity for the rest of the war . 162
In the Kansong-Kosong-Sokcho Ri coastal region, Comstock
(LSD-19), 7 LCVPs, Mainstay (AM-261), Partridge (AMS-31),
Redhead (AMS-34), and Swallow (AMS-36) swept 13 mines on
February 2, 1951. Partridge experienced engine trouble during
the operation and was swept by rough weather into a mine that -
somehow was in waters that had been well swept, and sunk. 163
From December 13 to 16, 1951, Curlew (AMS-8), and Swallow
(AMS-36) cleared 19 mines from Songjin harbor. Dextrous (AM-
341) Murrelet (AM-372), and LST-799 aided in the search on the
last two days. 164
In an unusual event that has become known as the "Nootka
incident," a Canadian Tribal class destroyer captured a
minelayer. On September 22, 1952, late at night near
Chinnampo they unsuccessfully chased a minelayer. The ship
disappeared back up a coastal waterway. Shortly after
midnight, September 22/23, the Nootka discovered a second
vessel leaving the Taedong estuary. Moving in at high speed
they caught the ship after firing several shots at it. The
71
minelayer's crew had abandoned the vessel in an attempt to
escape in small boats. When challenged by small boats from
the Nootka, a brief firefight ensued. Although the majority
of the crew escaped to the shore, two lieutenants, three chief
petty officers, and a few crewmen were captured. The men
cooperated and outlined the recently laid minefields in the
area . 165
In addition to besieging North Korean cities, bombarding
enemy troop positions, and sweeping fire support channels and
assault beach areas, the navy also participated in
diversionary amphibious assaults designed to cause the enemy
concern about the real possibility of such assaults. The idea
was to compel the enemy to shore up defenses along the coast
by drawing troops away from the front lines. The first such
feint was targeted at Chinnampo and the Taedong estuary. On
February 27, 1951, Carmick (DMS-33) and two ROKN YMSs began a
two day job clearing the approaches. The amphibious group
arrived on March 3 . They ran in near the shore before
retiring to the south. 166
In a more daring and costly effort, the army, air force,
and navy coordinated for a feint at Kojo. The difference this
time was that only the top commanders knew this was not a real
assault. D-Day was set for October 15, 1952. The
minesweepers arrived and began sweeping in close to the shore.
Shore bombardment and fighter activity increased. They hoped
to draw nearby enemy units into the open so that regular army
72
units with naval gunfire support could eliminate them. The
187th Regimental Combat Team prepared for an airborne assault,
while the 1st Cavalry Division would move by sea. In the end
the operation failed to draw the enemy out due to the speed of
our actions and the slow reaction of the North Koreans, who,
lacking motorized transport, could reach the area only on
foot. Enemy shore batteries, however, made the feint costly
for the United States as they took a toll on the
minesweepers. 167 Osprey (AMS-2 8) sustained damage from a near
miss by a 76mrn shore gun. Four crewmen were injured by the
blast.
Until the end of the war, the West Coast Island Defense
Unit (WCIDU) and its east coast counterpart ECIDU reported on
the enemy mining activities. When the war ended the
withdrawing U.S. troops took the villagers on the occupied
islands with them to protect them from reprisals . 168
With the end of the war, the navy issued orders to
prevent the enemy from having any excuse to accuse the U.S. of
violating the Armistice. They were issued to CTF 95 as
follows:
a. ROKN vessels were confined to areas south of the demarcation lines and after 15 August all U.N. patrols were restricted to South of the demarcation line. b. No visiting or searching of suspicious craft was permitted. c. Patrols were required to remain outside the three mile limit when north of the demarcation line. d. Patrols were directed to take evasive action when subjected to enemy fire, rather than return fire.
73
Fortunately no violations of the Armistice occurred and
hostilities came to an end. 169
The last two-and-a-half years of the war were spent
primarily check sweeping (see Figures 12 and 13) . Only two
major incidents had to be dealt with: the ongoing siege of
Wonsan and the floating mine problem.
74
LEGEND AIICA CHCLOHO llr SOLIO LIHCS
SWfi'T IT OWS'e TOll IIOOIICO TO 10 TT. JAH : Ill.
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Figure 12. EAST COAST COASTAL SWEEP FROM YANGYANG TO SUWON DAN
Source: CINCPACFLT Interim Evaluation Report 2, volume 11, 1426.
75
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HYDROPAC 8 IHSHOAE SWEEP LINES [AST C.OUT Of I(X)Hf.l
Figure 13.EAST COAST COASTAL SWEEP FROM SUWON DAN TO SONGJIN AREA
Source: CINCPACFLT Interim Evaluation Report 5, volume 7, 47.
76
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COIHOOf.
CHAPTER IV
THE SIEGE OF WONSAN AND
THE FLOATING MINE THREAT
After the Chinese intervention and subsequent winter
offensive the North Koreans regained control of Wonsan from
the retreating allies. Once ~n possession, remining,
necessary in view of the American amphibious ability, began in
earnest with Soviet mines and technical help . 170
With the Chinese "intervention" in mid-November 1950,
United Nations forces began a fighting withdrawal. On the
west coast, the Communists pressed forward, while in the east
the Marine withdrawal slowed the enemy advance considerably.
The Marines withdrew by sea from Hungnam under the protection
of NGFS ships, which kept the Communist forces out of the
city.
At Wonsan the defenders held firm. Shortly after the
harbor was officially declared completely clear of mines on
December 4, 1950, the United Nations forces withdrew to the
next line of defense farther south.
In an effort to restrict enemy junk traffic and
minelaying and to tie down as many enemy troops as possible,
United Nations forces made a bid to seize Wonsan harbor's
outer islands. The navy, with the aid of South Korean
Marines, seized Yo Do and Ko-to islands, which control harbor
traffic quite effectively. The lack of a reaction among the
77
North Korean forces holding the city caused United Nations
forces to quickly seize islands further in. Plans were laid
to begin the siege in early February 1951. Foul weather,
however, hindered bombardment for 13 days . 171 The siege, begun
on February 16, 1951, was the longest continuous siege in
naval history.
Wonsan was not the only city held under siege, but it was
the most important. The port of Songjin, north of Hungnam,
was also placed under siege in March, 1951. 172 Wonsan was the
second most important city in North Korea next to the capitol,
Pyongyang, and the largest seaport. Like Pyongyang, Wonsan
was a center of the national rail and road transportation
network. It had connections to almost every major city on the
peninsula. It also had a direct rail link to Vladivostok. By
holding the islands in the harbor, U.N. forces prevented
resupply by sea and forced the enemy to divert troops and
material away from the front to defend the city from attack.
Amphibious assault, or the threat of it, compelled the
enemy to deploy thousands of troops to protect this important
hub. Along with the influx of troops, the civilians were
cleared out for protection. With mining again under way, U.N.
minesweepers had to clear the harbor and its approaches once
more. The minesweepers cleared 54 square miles of space for
the gunfire support and bombardment ships . 173
The North Koreans responded to these U.N. efforts by
building up their artillery and garrison forces to oppose the
78
bombardment, and by remining the harbor. The enemy placed
200 new mines in Wonsan harbor from March 25-30, 1951. 174 Of
the 28 mines swept from Korean waters in March, 1951, 20 came
from Wonsan. The minesweepers were frequently taken under
fire by enemy shore batteries, on which occasions,
accompanying gunfire support ships provided counter battery
fire. 175 The struggle between the opposing sides, the enemy
wishing to retain control of Wonsan and the U.N. forces
endeavoring to tie down enemy troops and gain a better
bargaining position at the peace table, lasted an incredible
861 days without any give by either side . 176
When the sweepers first began the job of clearing Wonsan
harbor for the siege, they went about their task unmolested by
the enemy shore batteries. In fact, it was so peaceful that
when the pilot of the helicopter spotting mines for the
minesweepers had to use the restroom, he landed at the city
airfield and used their facilities. The North Koreans were so
surprised by his visit they did not even try to stop him.
Once the destroyers arrived and began their bombardment, the
enemy batteries opened up on the minesweepers, for the
minesweepers cleared the way for the bombarding ships to fire
into the city and the troops, trains, and supply vehicles that
pas sed through it . 177
In addition to the sea-going minesweepers were the
minesweeping boats
launches and LCVPs.
(MSBs) . The MSBs were converted 40 foot
They were slow, had a shallow draft, and
79
had a low magnetic signature. These boats were especially
useful for clearing the shallow waters near shore, usually
operating directly beneath the enemy guns . 178 Obviously, the
naval gunfire support ships did not need to go inshore, but
such clearance, which was carried out in clearing Wonsan for
the landing, gave credence to the fear of an amphibious
assault.
Sweeping was done by a group of five ships, with four
sweepers and one destructor vessel carrying an EOD team.
Moored mines located and cut free by the minesweepers were the
targets of the destructor boat's hostility. 179 Sinking the
floaters, all of which had to be eliminated, was a very trying
job at Wonsan. There were not only those moored mines cut
adrift by minesweepers, but also floaters that broke loose
from their moorings, or were deliberately set adrift.
The minesweepers were not the only units to destroy
mines. On March 1, 1951, the navy was informed by Korean
agents that a trainload of Russian mines was being unloaded at
Kalma Gak. On the 7th of March the light cruiser Manchester
(CL-83) sailed into the Wonsan harbor swept bombardment
channel and pounded the rail area with her 6" guns until a
massive explosion marked the end of at least one boxcar of the
offending mines, after which it left. 180
The work of the minesweepers eased a bit when LST 799
arrived at Wonsan. She had been converted to a badly needed
helicopter base and a minesweeper tender. 181 This one vessel
80
enabled the minesweepers to remain on station without
returning to Sasebo for routine repairs and replenishment.
In the face of the U.N.'s overwhelming naval strength,
the enemy developed new methods of mining the harbor. Sampans
often went out at night. Fishing boats carried mines tied to
their bottoms, which they planted by simply cutting the
connecting lines. Extensive use of floaters also harassed
U.N. operations. 182 The enemy used a new Russian self-planting
mechanism, which used a hook attached to an oil drum, log, or
other floating object to carry the mine. When a water soluble
restraining washer dissolved, the mine was released. This
resulted in the creation of irregular minefields, which were
harder to clear, and they afforded a no-risk method to mine
already cleared areas which were under U.N. surveillance. The
MYaM ground magnetic induction mine could also be affixed to
the mechanism resulting in the planting of these shallow water
ground mines. MSBs discovered an MYaM type mine in the
Hatchery area of Wonsan harbor and had to declare it offlimits
to shipping. 183
Life had been eased somewhat by the ROK Marines, who had
seized Yo Do island on February 14, two days before the siege
began removing the threat of enemy fire from there for the
minesweepers clearing the harbor for the bombarding ships that
would arrive in two more days . 184 The minesweepers often
worked at night under the harsh glare of starshells and
81
parachute flares, as working at night offered some protection
from shore batteries. 185
On March 30, 1951, 15 new M26 mines were swept,
confirming the unidentified radar contacts from the previous
nights . 186 Five months later two floating objects believed to
be fish or submarine type mines were sunk but confirmation of
what type of mine they were was not forthcoming . 187
From May 1 to December 31, 1951, 317 moored contact mines
and 8 magnetic mines were swept at Wonsan alone. 188 The
majority of the mines swept after 1950 came from Wonsan
harbor. From January 1 to June 30, 1952, of the 197 mines
encountered, 141 were at Wonsan. 189
The current, slower here than on the west coast, caused
mines to continue to "creep" along the harbor floor among the
areas cleared by the minesweepers as the minesweeper Gladiator
(AM-319) discovered. Early in 1953, while anchored in the
outer harbor waiting out heavy seas, their anchor dragged and
eventually caught, holding them fast. In the morning, as they
weighed, a mine came up attached to the anchor. Before the
crew could react one of the mine's horns smashed against the
ship's bow. When the mine failed to detonate, the crew
quickly veered the chain. After dropping the anchor to the
harbor bottom then hauling it in partially, then repeating the
dangerous process several times, Gladiator finally managed to
dislodge its unwelcome guest . 190
82
On occasion the minesweeping force got a break, such as
when ROK intelligence questioned a defector from the North
Korean Navy based at Kojo, a town 39 miles south of Wonsan,
who revealed that anti-landing craft mines had been sown ~n
the harbor as protection against an amphibious assault . 191 The
news was welcome as it averted a possible disaster, for the
MSBs were mostly converted landing craft.
Shore battery fire was the minesweepers' worst enemy.
The only way to avoid it was to sweep at night, an operation
for which the sweepers were ill-equipped. Without an
effective radar unit or mine locating sonar, night sweeping
operations were hazardous as the minesweeper might run into a
mine or run aground, as sometimes happened. As a result, most
of the damage inflicted on minesweepers during the war came
from the shore, not the sea. Destroyers often followed behind
the little ships to provide counterbattery fire when an enemy
battery attempted to engage them. Sometimes the minesweepers
were overlooked by the shore batteries. One minesweeper kept
sweeping while nearby shore batteries pounded a friendly
island; to have made smoke and zigzagged out of the area would
have only drawn attention to the ship and made it a target . 192
All ships conducting nighttime sweeps had to meet the
following criteria: (a) daytime helicopter reconnaissance; (b)
moonlight to get visual bearings; (c) no magnetic sweeping by
MSBs; (d) only one pass without echelon formation so no one
83
runs into a cut mine; and (e) smooth ocean for spotting cut
mines . 193
In May, 1951, shore batteries were moved to Ilari Point
on Kalma Gak. On the 17th, the batteries opened fire on the
minesweepers' nighttime anchorage around Yo Do island. 194 With
the safety of the anchorage compromised, the ships were forced
to move.
From February 1953. until the end of the war in July, 13
U.N. vessels were fired on by the North Korean guns. 195
Fortunately during this period, few hits were achieved and no
major casualties sustained. The threat of significant damage,
like that sustained on October 20, 1952, at Songjin, by
Thompson (DMS-38), which had been taken under fire by enemy
shore batteries, was ever-present. That day the ship
sustained five hits from 105mm or 155mrn guns causing extensive
damage to the ship and killing 3 men, while wounding eight.
During the Korean War, shore batteries scored hits on 21 U.S.
and 4 ROKN ships killing 11 men and wounding 35.
By no means were these the only duties of the tiny
minesweeping force. On occasion the minesweeper's crew would
give up much needed rest in order to catch the minelayers in
the act. In Operation Flycatcher, a recurring operation, the
minesweepers would wait at night looking for any sign of enemy
h . 1 196 minelaying and then descend upon and destroy t e m~ne ayers.
They also participated on occasion in repelling sampans
massing to attack friendly islands. 1 n A vessel of the
84
minesweeping force, Hitchiti (ATF-103), helped refloat ROKN
PC-704 after she ran aground on May 11, 1951. 198
Not all missions ended happily. One of the
reconnaissance pilots, a lieutenant (junior grade), was on a
rescue mission when his helicopter capsized in the sea
resulting ~n its loss. He pushed the people aboard his
aircraft into the two remaining helicopters, refusing to leave
until everyone else was rescued. When the overloaded
helicopters deposited their passengers and returned to search
for him, the heroic pilot could not be found. 199
The Floating Mine Threat
During and after the Russo-Japanese War of 1904-05,
unmoored floating mines had been found far from the war zone,
usually with explosive results. Due to the threat they posed
to neutral shipping, the Hague Conference of 1907 banned their
use.
The Korean War era threat from floating mines stemmed
from the fact that neither the Soviet Union nor North Korea
had ever signed the Hague Convention. The Russian mines
provided to the North Koreans therefore lacked sterilizers,
and they posed a grave danger to neutral as well as U.N.
shipping. 200
The currents along the Korean peninsula run north to
south and thence across the shipping lanes to Japan; the full
scope of the danger posed by floating mines thus can easily be
85
seen. 201
Floaters required only fifteen days to complete the
transit from North Korean waters down the southern coast.
They could easily be launched from junks and sampans. 202 on
September 7, 1950, HMS Jamaica and Charity sighted and
destroyed the first two floaters of the war at Changsangot,
near Chinnarnpo. 203 From then until September 30, 25 floaters
were spotted. 204
One reason for the initial landing at Wonsan, and later
for the long siege, was that the many estuaries in the area
provided good launch vehicles for floaters. Continuous
attention was given this port to curb the flow of these
menaces and thus protect shipping. 205
The number of drifting mines continued undiminished early
in the war. From September 29 to October 23, 1950, 45
floaters were encountered on both coasts (see Figures 14
through 18) . From then until November 15, 35 more floaters
were sighted in the Chinnarnpo area alone. Many of these mines
were destroyed by Mariner and Sunderland flying patrol boats
using . 50 calibre machine guns on strafing runs. 206
With the Russian mines remaining armed after being turned
loose, floating mine sightings began corning in from the Sea of
Japan and the North Pacific. In June 1951, the destroyer
Walke (DD-723), which was stationed 60 miles offshore with the
carrier task force, ran into a floater, suffered serious
damage to the port side aft, and lost 25 men. 207 By October of
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93
1951, over 300 Russian mines had washed up on the shores of
Japan. 2oa
As the war dragged on and the blockading ships moved
farther offshore, the number of mines encountered in the fire
support channels dropped. This is partly due to increased
patrolling. · The percentage of the mines encountered that were
floaters naturally increased. In April, 1952, 13 of the 33
mines encountered were drifters. 209
Some of the floaters were legitimately torn loose from
their moorings by bad weather. In mid-August, 1952, Typhoon
Karen swept through Korean waters resulting in 37 floaters. 210
One of these mines was struck by the fleet ocean tug Sarsi
(ATF-111) . The 37 floaters comprised most of the 54 mines
encountered that month. 211
September saw over 40 floaters sunk in the Sea of Japan.
One of the drifting terrors floated 90 miles east of Wonsan
where the destroyer Barton (DD-722) struck it on September 16.
"Just before his ship hit the mine, Conunander H.B. Seim had
read a report stating that a ship making more than ten knots
was safe from floating mines as the bow wave pushed them
aside. Barton's 15 knot bow wave didn't push quite far
enough . " 212
side. 213
Barton survived with a five foot hole in her
In February, 1953, 10 of the 12 mines sighted and sunk
were floaters. 214 April caused serious concern as "not since
August 1952, when a typhoon swept the Korean area, have so
94
many mines been encountered. "215 Even when the war ended in
late July, 1953, the majority of the mines were floaters,
comprising 11 of the 13 mines encountered. 216 From February
until July 1953, 93 mines were encountered, 81 of which were
floaters. All of them were on the east coast (see Table 4) . 211
TABLE 4
NUMBER OF FLOATING MINES SIGHTED
Date September 4-September 31, 1950 September 29-0ctober 23, 1950 October 23-November 15, 1950 March, 1951 May 1-December 31, 1951 January, 1952 February, 1952 March, 1952 April, 1952 June, 1952 August 16-September 30, 1952 February, 1953 March, 1953 April, 1953 May, 1953 June, 1953 July, 1953
Mines 25 45 35
7 11 14 23 24 13
5 37 10 14 21
9 19 11
Note: The table is incomplete as some documents pertaining to the Korean War are still classified.
Source: Cagle and Manson, "Wonsan: The Battle of the Mines," CINCPACFLT Interim Reports, MINRON 3 War Diary, Action Report Serial 0119, and COMNAVFE Command and Historical Reports.
There can be little doubt that the floating mines were
anything other than a deliberate use of a deadly weapon
outlawed by the Hague Convention. Storms accounted for some
of them but in most cases there were no storms to produce the
95
many floating mines detected. Some authorities still believe
that all of the drifting mines sighted were the result of
natural causes as anything else would be a violation of the
1907 Hague Convention and the Soviets deneid they were doing
it. 218 The fallacy of this position is immediately obvious
from an investigation of the records. Eighty-one floating
mines were encountered during the last six months of the war.
According to naval records, from the end of the war "to 1
January 1954, there had been only one mine encountered. This
was an old floater estimated to have been in the water for
about two years. " 219 Thus the number of floaters sighted
during the six months prior to the end of the war was 81, and
the number sighted in the six months after the war was one.
These figures offer irrefutable evidence that many of the
floaters earlier encountered by United Nations forces had been
deliberately launched.
96
CHAPTER V
AFTERMATH AND CONCLUSION
The initial response to the losses at Wonsan was to
outfit landing craft with mine locating sonar so they could be
used in that function. The World War II UOL MK4 short-pulse,
high-frequency sonic imaging device had by 1950 evolved into
the AN/UQS-1 mine locator. Tests were run in Korea using
these units, but they performed poorly in the colder seas.
Similar experimentation in radar produced the SO and su types,
which proved to be of great value to night mine sweeping
operations. 220
There were also some wooden-hulled minesweepers built as
a result of the discovery of magnetic mines. 221 The Bureau of
Ships turned to Philip L. Rhodes, who had designed
minesweepers in the Second World War, for a new ship design.
The result was the 172 foot Aggressive class fleet ocean
minesweeper, designated MSO. It used a Packard or General
Motors non-magnetic engine, controllable pitch propellers,
wooden-hulled construction, and an improved minehunting sonar.
The 780 ton Acme class and 750 ton Agile class MSOs were also
built. The ships of the Aggressive class represented the
epitome of 1950s mine warfare ship construction. Sixty-five
of these ships were built for the United States Navy. Many
ships were converted, and 159 coastal minesweepers, MSCs,
were also built. These ships were equipped with controllable
97
pitch propellers and separate engines to generate power for
magnetic rninesweeping. All but 20 of the MSCs were turned
over to our allies under the Military Defense Assistance
Program (MDAP) . The recipients included South Korea, Mexico,
Norway, Peru, Philippines, Taiwan, Uruguay, Burma, and the
Dominican Republic. 222 One new rninehunter, Bittern (MHC-43) ,
was also built. Perhaps most indicative of the mine warfare
lessons of the Korean War, and Wonsan in particular, was the
decision to specially produce 36 foot rninesweeping boats
(MSBs) to replace the converted LCVPs.
In a truly revolutionary move, the Navy began testing a
helicopter-towed rninesweeping array. The idea formed during
the Korean War when helicopters proved their worth to
rninehunting efforts as reconnaissance units. The towed arrays
were tested at the mine countermeasures station at Panama
City, Florida, but with little progress due to unreliable
funding. 223 The idea carne to fruition years later, and the
systems were used during Operation End Sweep in Haiphong
harbor at the end of the Vietnam War.
The new MSOs and MSCs were equipped with automatic
degaussing systems, as well as other features to defeat mines
of types not even encountered in Korea, such as acoustic and
pressure mines. And in a step in the other direction, Liberty
ships were converted into guinea pig vessels for use in check
sweeping, after the effectiveness of the Japanese ship Soei
Maru was proved. 224 The Soei-Maru did check sweeping
98
operations at ports below the 38th parallel during the Korean
War. The successful use of this vessel lightened the burden
on United States minesweepers for the important combat sweep
operations.
An unusual experimental effort was the XMAP (Experimental
Magnetic, Acoustic, and Pressure Sweep) towed array project.
It was a 250 foot long, 2, 880 ton steel cylinder that was
supposed to counter all influence mine types in one pass.
After large cost overruns and poor performance, the project
was finally allowed to die a humble death.
The disaster at Wonsan compelled the nation to rebuild
the mine warfare force to the state in which it should have
been maintained following World War II. With the conversions
and new construction, including 65 MSOs, 22 MSCs, and one
minehunting vessel, the United States Navy possessed a total
of 333 mine warfare ships. An impressive array of 180 new
ships had been added to the fleet, which boasted 93 active
minesweepers. 225
One of the more important changes for the mine forces was
the reestablishment of the Mine Force Pacific Fleet (MINEPAC)
in January, 1951, which signalled a continuing commitment to
mine warfare. 226 Joining in on the scientific front was the
Mine Advisory Committee (MAC}, established in 1951 with some
of the faculty of the Catholic University, and later moved to
the National Academy of Sciences. They were responsible for
99
conducting a systematic study of mine warfare technology; many
pioneering technical studies resulted from their efforts. 227
Naval intelligence, especially that obtained from
helicopter spotters, was very important during the war. The
reports from air and surface forces helped assess the mine
threat during the war. With good intelligence, minefields
such as the ones at Wonsan, Chinnampo, and Hungnam, could be
cleared with relative ease. The harbor and river pilots who
cooperated with U.N. forces helped outline the fields. In
some cases, intelligence about shipments of mines caused their
destruction before they reached their destination.
The enemy used the MKB chemical horn contact mine, the
M26 inertia contact mine, and the MYaM ground magnetic
induction mine. Several other types were also in limited use.
The liberal use of floating contact and magnetic mines also
complicated operations. 228
Fortunately for the u.s., experienced Japanese
minesweeper crews, who had spent the years since the end of
World War II sweeping the waters around Japan, were on hand to
take up the slack until reinforcements could arrive, although
Their the method of their contracting was questionable.
efficiency in the use of the guinea pig ship Soei-Maru in
check sweeping operations prompted U.S. interest in keeping
. t 229 some guinea pig vessels in every strateg~c por .
Despite the lack of vessels, parts, and trained men, the
minesweeping force (TG 95.6) did a remarkable job. They swept
100
the assault beaches, the bombardment channels, and gunfire
support channels, all of which were maintained until the end
of the war. They faced determined remining and intense shore
battery fire. Mine countermeasures changed dramatically
during the war. A lack of ships forced many innovations.
Indeed, innovations ~n minesweeping gear, mine hunting
tactics, and mine disposal were earmarks of this war.
Admiral C. Turner Joy felt that neglecting mine warfare
was a foolish mistake as any alert enemy who could use mines
intelligently could stop or hinder u.S. naval operations. 230
The North Koreans, with Soviet aid and assistance, did so,
and, for the expenditure of 3,000 obsolete mines sank five
ships, held off a 250 ship armada for five days, and
indirectly caused the United States to spend millions of
dollars on increased research and construction that otherwise
would have been unnecessary. For the enemy, the decision to
mine was a simple one. 231 The greatest problem is that such a
tragedy might occur again. As Admiral Duncan said, "we don't
seem to learn though, historically the Navy especially, never
pays much attention in peacetime to the passive or less
glamorous weapon systems. " 232 If a mine force exists, it
should not be reduced as Secretary of Defense Louis Johnson
reduced the u.S. Navy by 1950. 233 On the other hand, the U.S.
should not have fallen prey to the exaggerated psychological
impact mine warfare tends to produce in its victim. The
101
victim often views the threat as being vastly more significant
than it is. 234
After the initial shock of the losses was over, funding
for increased mine countermeasures slowly dried up after
1958.235
Many of our old vessels were retained even up until
the 1970s. The last of the Auk and Admirable class ships,
built in World War II and used extensively in Korea, were
removed from service on July 1, 1972. They were soon
transferred to foreign navies like the rest of their
predecessors. The Acme class MSO, commissioned in 1957 and
1958 were eliminated in 1976. The last three active Agile
class MSO, commissioned from 1952 to 1956, remained in service
in 1979 for research purposes in Panama City. Twenty more
were in the Naval Reserve Force and 10 were mothballed. 236
Although during the crisis the U.S. Navy built up a large
mine sweeping fleet, many of the vessels were subsequently
mothballed or sold.
In 1987, during the Iran-Iraq war, reflagged Kuwaiti
tankers faced a threat from mines laid by Iran in the Persian
Gulf. This threat was intensified by the fact that these
supertankers were restricted to the deep water channel close
to the Iranian coast. Complicating the United States pledge
to protect these ships was the total lack of minesweepers in
the Gulf area. On July 24, 1987, the tanker Bridgeton became
the first victim of an Iranian mine. Within a short period,
six minesweepers and a few minesweeping helicopters arrived in
102
the Persian Gulf, proving once again the unfortunate fact that
resolute action in mine warfare could only be undertaken after
losses had been sustained. By year's end, 13 minesweepers
were at work. With the old Korean War-era minesweepers' state
of the art equipment, the U.S. Navy was still unprepared to
counter World War I vintage mines. 237
Visions of ships like the frigate Samuel B. Roberts (FFG-
58), which hit a mine on April 14, 1988, ~n the Persian Gulf
and had a 20 foot hole torn ~n the hull, as well as a broken
keel and other damage, were still recent memories when the
United States again became involved in the area during Desert
Shield and Desert Storm. On February 18, 1991, the amphibious
carrier Tripoli (LPH-10) hit a mine 50 miles off Kuwait,
suffering a 16 by 25 foot hole in her hull. The ship managed
to stay on station to continue supporting the minesweeping and
amphibious assault operations. Soon afterwards a mine
detonated under the keel of the guided missile cruiser
Princeton (CG-59) cracking the hull.
In 1989-1990, the United States Navy's entire mine
countermeasures force totalled 20 Korean War-era MSOs in
active and reserve fleets, 21 RH-53D helicopters, and 7
MSBs. 238 Even with an expanded construction program planned
after Desert Storm, recent budget cuts are almost certain to
result in a reduction of the construction program to preserve
active ships.
103
In the early phases of the Korean War, the United States
was totally unprepared to undertake mine clearance due to the
cutbacks of previous years. There were far too few ships
trying desperately to cover all the gaps. As a result the
enemy succeeded in delaying amphibious operations and shore
bombardments. The United Nations naval forces suffered heavy
casual ties, the loss of several small vessels, and severe
damage to many larger ships.
America's neglect and subsequent rush to compensate for
that neglect in the late 1980s and early 1990s, only to
sacrifice such mine warfare advances as were made during this
latest crisis period, repeats with remarkable consistency the
sad cycle of neglect, accelerated attention, and gradual
neglect which characterized the Korean War years just four
decades ago. No need could be more clear in the 1990s; yet
the lesson, it seems, will be less heeded.
104
ENDNOTES
1The Reminiscences of Admiral Charles K. Duncan, USN
(Ret.), 4 vol. (Annapolis: U.S. Naval Institute Oral History Interview, Operational Archives, Naval Histo~ical Center, Washington, D.C.), 346-347 (hereafter cited as Admiral Duncan) .
2Harry K. Griffin, "The Navy in Korean Waters," Army Information Digest 12 (1951): 13.
3 Ibid., 18.
4 Ibid., 12.
5C.W. Saar, "Offensive Mining as a Soviet Strategy," U.S. Naval Institute Proceedings 90 (August 1964): 45.
6Cornrnander In Chief Pacific Fleet Report 1, vol. 6 (Wilmington, Delaware: Inc., 1978), 1088 (hereafter cited as Report 1) .
Interim Evaluation Scholarly Resources CINCPACFLT Interim
7Gregory K. Hartmann, Weapons That Wait: Mine Warfare in the U.S. Navy (Annapolis: Naval Institute Press, 1979), 78.
8Cornrnander In Report 6, vol. 1 Center, Washington, Interim Report 6) .
Chief Pacific Fleet Interim Evaluation (Operational Archives, Naval Historical D.C.), 9 (hereafter cited as CINCPACFLT
9Malcolm w. Cagle and Frank A. Manson, "Wonsan: The Battle of the Mines, " U.S. Naval Institute Proceedings 8 3 (June 1957) : 611.
10Arnold s. Lott, Most Dangerous Sea: A History of Mine Warfare (Annapolis: Naval Institute Press, 1954), 268, 269.
11Ibid., 270.
12 Ibid., 277.
13Ibid., 285.
l 4Harry w. Edwards, "A Naval Lesson of the Korean War," U.S. Naval Institute Proceedings 80 (December 1954): 1338.
15Andrew Patterson, Jr., "Mining: A Naval Strategy'" Naval War College Review 97 (May 1971): 54.
105
16Howard S. Levie, Mine Warfare and International Law (N.p., 1972), 100.
17 Ibid., 113.
18Patterson, 54-55.
19Tamara Moser Melia, "Damn the Torperdoes:" A Short History of U.S. Naval Mine Countermeasures, 1777-1991 (Washington: Naval Historical Center, 1991), 72.
20Malcolm W. Cagle and Frank A. Manson, The Sea War in Korea (Annapolis: U.S. Naval Institute Press, 1957), 124.
21Cagle and Manson, "Wonsan: The Battle of the Mines," 599.
22CINCPACFLT Interim Report 6, 1: 9.
23CINCPACFLT Interim Report 1, 2: 102.
24Cagle and Manson, The Sea War in Korea , 125.
25Me 1 i a , 57 , 61 .
26Griffin, 12.
27Lot t, 2 6 9 .
28Melia, 69.
29CINCPACFLT Interim Report 1, 6: 1091.
30Melia, 69.
31James A. Field, A History of United States Naval operations: Korea (Washington: Department of the Navy, 1962),
231.
32Cagle and Manson, The Sea War in Korea, 127.
33 Ibid., 126.
34Admiral Duncan, 345.
35CINCPACFLT Interim Report 1, 6: 1091-1092.
36Melia, 68.
37Cagle and Manson, The Sea War in Korea, 125.
106
601.
38 Ibid.
39Cagle and Manson, "Wonsan: The Battle of the Mines,"
4°Field, 232.
41Cagle and Manson, The Sea War in Korea, 126.
42CINCPACFLT Interim Report 1, 6: 1092.
43 Ibid., 1095.
44War Diary, Commander Mine Squadron 3(1), August, 1950-August, 1951, Operational Archives, Naval Historical Center, Washington, D.C., August, 1950, 2 (hereafter cited as MINRON 3 War Diary) .
45Commander Naval Forces Far Report, June 26-August 31, 1950, File, Operational Arhcives, Washington, D.C., chapter 2, 14 Command and Historical Report) .
46Field, 231.
East, Command and Historical Post 1 January 1946 Command Naval Historical Center, (hereafter cited as COMNAVFE
47CINCPACFLT Interim Report 1, 6: 10 95.
48Walter Karig, Malcolm W. Cagle, and Frank A. Manson, Battle Report: The War in Korea (New York: Rinehart and Company, Inc., 1952), 67.
49CINCPACFLT Interim Report 1, 6: 1149.
50 Ibid., 6: 1097.
51Karig et al., 172.
52COMNAVFE, Command and Historical Report, SeptemberNovember 1950, chapter 2, 9-10.
53Cagle and Manson, The Sea War in Korea, 131.
54CINCPACFLT Interim Report 1, 3: 361.
55Ibid., 6: 1088, 1089.
56Field, 183.
57CINCPACFLT Interim Report 1, 6: 1088.
58 Ibid. , 1 : 9 ·
107
sgcagle and Manson, The Sea War in Korea, 131.
6oCINCPACFLT Interim Report 1 r 3 3 : 62. 61J
. ames Cotton and Jan Neary, eds., The Korean war in H~story (Atlantic Highlands N J . -:-H:-----7' . ...;;;t;..:."-=;.:_....:..:...:==-----=.:..:. I t · r • • • uman~ ~es Press n ernat~onal, Inc., 1989), 127, 129, 130.
62R· h ~c ard T. Spofford, Officer Biographies, Operational
Archives, Naval Historical Center, Washington, D.C., 1.
63Cagle and Manson, "Wonsan: The Battle of the Mines, "
599.
64Griffin, 13, 22.
65CINCPACFLT Interim Report 1, 1: 9.
66 b. I ~d. , 6: 10 9 6.
67Lott, 268.
68Field, 231-232.
69Admiral Duncan, 345, 346.
7°Karig et al. , 195.
71Lott, 270.
72Griffin, 12.
73Lott, 271.
74Edwards, 1340.
75Robert Debs Heinl, Jr., Victory at High Tide (New York: J.B. Lippincott Company, 1968), 27, 81, 82, 83.
76MINRON 3 War Diary, September, 1950, 5.
77Lynn Montross and Nicholas A. Canzona, The Inchon-Seoul Campaign, U.S. Marine Operations in Korea, 1950-1953, vol. 2 (Washington: Historical Branch, G-3, Headquarters, U.S. Marine Corps, 1955), 83.
78Heinl, 85.
79Action Report, Commander Mine Squadron 3, Serial 0119, March 10, 1951, Operational Archives, Naval Historical Center, Washington, D.C., 9.
108
80Lott, 271.
81Melia, 73.
82CINCPACFLT Interim Report 1, 3: 365.
83Melia, 73.
84COMNAVFE Command d · an H~storical Report, September-November, 1950, chapter 2, 9-10, 12.
85Karig et al., 281-283.
86Ibid.
87 Ibid., 284.
88Lot t , 2 7 3 .
89Ibid., 272-273.
9°Field, 217.
91CINCPACFLT Interim Report 1, 1: 9.
82Karig et al. , 342.
93CINCPACFLT Interim Report 1, 6: 1133-1134; MINRON 3 War Diary, October, 1950, 2-3.
94Cagle and Manson, "Wonsan: The Battle of the Mines, " 598; Karig et. al, 298.
95Melia, 73.
96Lott, 272.
97Field, 233.
98James F. Schnabel, Policy and Direction: The First Year, United States Army in the Korean War (Washington: Office of the chief of Military History, Department of the Army, 1972), 205-206.
99Melia, 77.
10°Karig et al., 315.
101Field, 232.
109
102Lynn Montross and Nicholas A. Canzona The Chosin Reservoir Campaign, United States Marine Operations in Korea, 1950-1953, vel. 3 (Washington: Historical Branch, G-3, H7adquarters, United States Marine Corps, 1957), 27; war D~ary, October, 1950, 4.
103Cagle and Manson, The Sea War in Korea, 134.
104Field, 233.
105Cagle and Manson, The Sea War in Korea, 135.
106Resurne Report-Tailboard, Commander Mine Squadron 3, Serial 024, November 27, 1950, Operational Archives, Naval Historical Center, Washington, D.C., 1.
107Roy E. Appleman, South to the Naktonq, North to the Yalu, United States Army in the Korean War (Washington: Office of the Chief of Military History, Department of the Army, 1961), 633.
108Cagle and Manson, The Sea War in Korea, 136.
109Field, 233.
110MINRON 3 War Diary, October, 1950, 5.
111Karig et al., 305; Andrew Geer, The New Breed (New York: Harper adn Brothers Publishers, 1952), 192, other sources list different dates for the fall of Wonsan to ROK I Corps troops, this date was chosen as most of the sources agreed on this point.
112Appleman, 634.
113Field, 235.
114MINRON 3 war Diary, October, 1950, 5-6·
115Action Report, Mine Squadron Operational Archives, Naval Historical D.C., 3.
116Melia, 7 6.
3, Serial 0204, Center, Washington,
117Lieutenant Commander D' Arcy v. Shouldice to the Chief of Naval Operations, February 11, 1953, Po~t 1 ~anuary 1946 Command File, Operational Archives, Naval H~sto:~cal Center, Washington, D.C., 3, (hereafter cited as Should~ce) ·
118CINCPACFLT Interim Report 1, 5: 7 32 ·
110
11
~Action Report, Small Boat Minesweepers, Mine Squadron 3, Ser~al 01, November 30, 1950, Operational Archives Naval . . ' H~stor~cal Center, Washington, D.C., cover, 1.
610.
12°CINCPACFLT Interim Report 1, 3: 366.
121 Ibid., 1: 9, 3:362,365.
122Karig et al., 324.
123Ibid., 322-323.
124MINRON 3 War Diary, October, 1950, 11.
125Schnabel, 217.
126Karig et. al, 327.
127Ibid., 327-330.
128Cagle and Manson, The Sea War in Korea, 145.
129CINCPACFLT Interim Report 1, 6: 1089.
13°Cagle and Manson, "Wonsan: The Battle of the Mines,"
131MINRON 3 War Diary, October, 1950, 9.
132Field, 235; Action Report, Mine Squadron 3, Serial 0121, March 10, 1951, Operational Archives, Naval Historical Center, Washington, D.C., H.O. 6515.
133Schnabel, 2 0 9.
134CINCPACFLT Interim Report 1, 6: 1098, 1154-1155 ·
135Shouldice, 1-2.
136Karig et al., 324-325.
137Appleman, 634.
138Karig et al. , 332.
139Field, 243.
140Melia, 7 8.
141Lott, 27 8.
111
1420fficer B · h · ~ogra:p ~es, Stephen M. Archer, Operational Archves, Naval H~stor~cal Center, Washington, D.C., 1_ 2 _
143Cagle d M an anson, The Sea War in Korea, 153. 144Lott, 27 9.
l4SKarig t 1 358 e a ., , 359.
146Field, 237-238.
147Melia, 81.
148Lott, 27 9.
149Field, 240.
15°Karig et al., 361.
151Ibid. , 3 62.
152Cagle and Manson, The Sea War ~n Korea, 159.
153Karig et al. , 35 9.
154Lot t, 2 8 0 .
155CINCPACFLT Interim Report 1, 6: 1132.
156Action Report, Mine Squadron 3, Serial 0019, November 3, 1950, Operational Archives, Naval Historical Center, Washington, D.C., 1-2.
157CINCPACFLT Interim Report 1, 6: 1137; Field, 249.
158Lot t , 2 81 .
159Billy C. Mossman, Ebb and Flow, November 1950-July 1951, United States Army in the Korean War (Washington: Center of Military History, United States Army, 1990), 155, 165, 210.
160MINRON 3 War Diary, November, 1950, 2-3.
161COMNAVFE, Command and Historical Report, OctoberNovember, 1952, chapter 2, 25-26; Comander in Chief Pacific Fleet Interim Evaluation Report 5, vol. 7, (Wilmington, Delaware: Scholarly Resources Inc., 1978), 1 (hereafter cited as CINCPACFLT Interim Report 5) .
162Walter G. Hermes, Truce Tent and Fighting Front, United States Army in the Korean War (Washington: Office of the Chief of Military History, United States Army, 1966), 328.
112
163A t. R t . c ~on epor , M~ne Squadron 3, Serial 0124 March 10 1951, Operational Archives, Naval Historical Center' Washington, D.C., 2-3. '
164A t. R . c ~on eport, M~ne Squadron 1, Serial 044, Operational Archives, Naval Historical Center, Washington, D.C., 1, 3.
165Cagle and Manson, The Sea War in Korea, 204-206.
166Field, 330.
167Robert F. Futrell, The United States Air Force in Korea, 1950-1953 (New York: Duell, Sloan and Pearce, 1961), 494-496; Melia, 82.
168Pat Meid and James M. Yingling, Operations in West Korea, United States Marine Operations in Korea, 1950-1953, vol. 5 (Washington: Historical Division, Headquarters, United States Marine Corps, 1972), 359.
169CINCPACFLT Interim Report 6, 8: 28-29.
17°F ield, 32 6.
171Sheldon Kinney, "All Quiet at Wonsan," United States Navla Institute Proceedings 80 (August 1954): 861.
172Field, 331.
173CINCPACFLT Interim Report 5, 7: 44.
174Commander in Chief Pacific Fleet Interim Evaluaiton Report 2 (Wilmington, Delaware: Scholarly Resour~es Inc·, 1978), 1770., (hereafter cited as CINCPACFLT Inter~rn Report 2) .
175Field, 331.
176Kinney, 85 9.
177 Ibid., 861.
h s · of Wonsan," Army 178Richard B. Phillips, "T e e~ge Information Digest 8 (November 1953): 42.
179Ibid., 43.
18°Field, 331.
181Ibid. , 345.
182Kinney, 8 62.
113
183Commander 1.n Chief Pacific Fleet Interim Evaluation
Report 4, vol. 8 (Wilmington, Delaware: Scholarly Resources Inc., 1978), 17 (hereafter cited as CINCPACFLT Interim Report 4) .
184Phillips, 45.
18~INRON 3 War Diary, February, 1951, 5.
186Ibid. , March, 1951, 7-8.
187Ibid., August, 1951, 13.
188Commander in Chief Pacific Fleet Interim Evaluation
Report 3, vol. 14 (Wilmington, Delaware: Scholarly Resources Inc., 1978), 23 (hereafter cited as CINCPACFLT Interim Report 3) •
189CINCPACFLT Interim Report 4, 8: 14.
190Phillips, 43.
191CINCPACFLT Interim Report 6, 8: 2 6.
192p. w. Rairden, Jr., "The Warfare," United States Naval (September 1953): 978.
Junior Institute
Officer in Mine Proceedings 79
599.
193CINCPACLFT Interm Report 4, 8: 27.
194MINRON 3 War Diary, May, 1951, 8.
195CINCPACFLT Interim Report 6, 8: 41.
196Kinney, 8 62.
197Phillips, 45-4 6.
198MINRON 3 War Diary, May, 1951, 6.
199Ibid., March, 1951, 8.
200Cagle and Manson, The Sea War in Korea, 131.
"Wonsan·. The Battle of the Mines," 2mcagle and Manson,
202CINCPACFLT Interim Report 1, 6: 1088.
2o3Cagle and Manson, The Sea War in Korea, 130.
204 Ibid., 131.
114
205Phillips, 41.
206CINCPACFLT Interim Report 1, 3: 363, 365.
2~Field, 358-359.
208CINCPACFLT Interim Report 3, 14: 12-13.
209COMANVFE Command and Historical Report, April, 1952,
chapter 2, 11.
21°COMNAVFE Command and Historical Report, August-September 1952, chapter 2, 11.
211CINCPACFLT Interim Report 5, 7: 5.
212Lott, 284.
213Commander in Chief Pacific Fleet Interim Evaluation Report 5, 7: 22.
214COMNAVFE Command and Historical Report, JanuaryFebruary, 1953, chapter 2, 18.
215COMNAVFE Command and Historical Report, March-April, 1953, chapter 2, 25.
216COMNAVFE Command and Historical Report, July, 1953, chapter 2, 18.
217CINCPACFLT Interim Report 6, 8: 1, 9.
218Levie, 143.
219CINCPACFLT Interim Report 6, 8: 2 9.
220Hartmann, 135; CINCPACFLT Interim Evaluation Report 6, 8: 3.
221Lott, 4 02.
222Hartmann, 141 .
223Melia, 85.
224 Ibid. , 83, 85.
225 Ibid. , 85, 87.
226Ibid., 83.
227Hartmann, 81.
115
228C INCPACFLT Interim Report 6, 1: 9.
229C INCPACFLT Interim Report 1, 6: 1147.
23°Cagle and Manson, "Wonsan: The Battle of the Mines," 611.
231Patterson, 56.
232Duncan, 34 7.
233Lott, 277.
234Patterson, 62.
235Melia, 8 6.
236Hartmann, 141 .
237Michael A. Palmer, On Course to Desert Storm (Washington: Naval Historical Center, 1992), 122, 123, 124, 129.
238Melia, 127, 128, 131.
116
BIBLIOGRAPHY
Unpublished Government Documents
OPERATIONAL ARCHIVES, NAVAL HISTORICAL CENTER, WASHINGTON, D.C.
Action Reports
Commander Mine Squadron 1. Serial 044. December 26, 1951.
Commander Mine Squadron 3, Serial 0119. March 10, 1951.
Commander Mine Squadron 3. Serial 0124. March 10, 1951.
Mine Squadron 3. Serial 0019. November 3, 1950.
Mine Squadron 3. Serial 0121. March 10, 1951.
Mine Squadron 3. Serial 0204.
Small Boat Minesweepers. Mine Squadron 3. Serial 01. November 30, 1950.
Command and Historical Reports (COMMANDER NAVAL FORCES FAR EAST) POST 1 JANUARY 1946 COMMAND FILE
June 26-August 31, 1950.
September-November, 1950.
September-October, 1951.
November-December, 1951.
January, 1952.
February, 1952.
March, 1952.
April, 1952.
June, 1952.
July, 1952.
August-September, 1952.
October-November, 1952.
117
December, 1952.
January-February, 1953.
March-April, 1953.
May-June, 1953.
July, 1953.
Interim Evaluation Report (COMMANDER IN CHIEF, PACIFIC FLEET)
Report 6.
Officer Biographies
Richard T. Spofford
Stephen M. Archer
Oral History
The Reminiscences of Admiral Charles K. Duncan, USN (Ret.). 4 vol. Annapolis: United States Naval Institute. Oral History Interview.
Miscellaneous Reports
Lieutenant Commander D'Arcy V. Shouldice to the Chief of Naval Operations. February 11, 1953. Post 1 January 1946 Command File.
Resume Report-Tailboard. Commander Mine Squadron 3. Serial 024. November 27, 1950.
War Diary. Commander Mine Squadron 3. August, 1950-August, 1951.
Microfilmed Government Documents
Interim Evaluation Reports (COMMANDER IN CHIEF, PACIFIC FLEET)
Report 1, Wilmington, Delaware: Scholarly Resources Inc., 1978.
Report 2, Wilmington, Delaware: Scholarly Resources Inc., 1978.
Report 3, Wilmington, Delaware: Scholarly Resources Inc., 1978.
118
Report 4, Wilmington, Delaware: Scholarly Resources I 1978. nc.,
Report 5, Wilmington, Delaware: Scholarly Resources I 1978. nc.,
Books
Applema~, Roy E. South to the Naktong, North to the Yalu. Un1. ted St?-tes Arm.y ~n the Korean War. Washington: Office of the Ch1.ef of M1.l1.tary History. Department of the Army 1961. .
Blackman, Raymond V.B. and Francis E. McMurtie eds. Jane's Fighting Ships, 1949-1950. New York: McG;aw Hill Book Company Inc., 1949.
Blackman, Raymond V.B., ed. Jane's Fighting Ships, 1950-1951. New York: McGraw Hill Book Company Inc., 1951.
Jane's Fighting Ships, 1951-1952. London: Sampson Low, Marston & Co. Ltd., 1952.
_______ . Jane's Fighting Ships, 1952-1953. London: Sampson Low, Marston & Co. Ltd., 1953.
-------:--· Jane's Fighting Ships, 1953-1954. New York: McGraw Hill Book Company Inc., 1954.
Cagle, Malcolm W. and Frank A. Manson. The Sea War in Korea. Annapolis: United States Naval Institute Press, 1957.
Cotton, James and Jan Neary, eds. The Korean War in History. Atlantic Highlands, N.J.: Humanities Press Int~tion
al, Inc., 1989.
Field, James A., Jr. A History of United States Naval Operations: Korea. Washington: Department of the Navy,
1962.
Futrell, Robert F. The United States Air Force in Korea, 1950-1953. New York: Duell, Sloan, and Pearce, 1961.
Geer, Andrew. The New Breed. New York: Harper and Brothers Publishers, 1952.
Hartmann, Gregory K. Weapons That Wait: Mine Warfare in the United States Navy. Annapolis: Naval Institute Press, 1979.
Heinl, Robert Debs, Jr. Victory At High Tide. New York: JB Lippincott Company, 1968.
119
Hermes, Wa~ter G. Truce Tent and Fighting Front. United states Army ~n the Korean War. Washington: Office of the Chief of Military History, United States Army, 1966.
Karig, Walter, Malcolm W. Cagle and Frank A. Manson. Battle Report: The War in Korea. New York: Rinehart and Company Inc., 1952.
Levie, Howard S. Mine Warfare and International Law. N.p. 1972. '
Lott, ArnoldS. Most Dangerous Sea: A History of Mine Warfare. Annapolis: Naval Institute Press, 1954.
Meid, Pat and James M. Yingling. Operations in West Korea. United States Marine Operations in Korea, 1950-1953. vol. 5. Washington: Historical Division, Headquarters, United States Marine Corps, 1972.
Melia, Tamara Moser. "Damn the Torpedoes:" A Short History of United States Naval Mine Countermeasures, 1777-1991. Washington: Naval Historical Center, 1991.
Montross, Lynn and Nicholas A. Can zona. The Inchon-Seoul Campaign. United States Marine Operations in Korea, 1950-1953. vol. 2. Washington: Historical Branch, G-3, Headquarters, United States Marine Corps, 1995.
The Chosin Reservoir Campaiqn. United States Marine Operations in Korea, 1950-1953. vol. 3.
Washington: Historical Branch, G-3, Headquarters, Ullted States Marine Corps, 1957.
Palmer, Michael A. On Course to Desert Storm. Washington: Naval Historical Center, 1992.
Schnabel James F. Policy and Direction: The First Year. United States Army in the Korean War. Washington: Office of the Chief of Military History, Department of the Army, 1972.
Articles
Cagle, Malcolm w. and Frank A. Manson. "Wonsan: The Battle of the Mines." United States Naval Institute Proceedings 83 (June 1957): 598-611.
Dempewolff, Richard F. "Mother of the Minesweepers." Popular Mechanics Magazine 97 (February 1952): 97-104.
120
Edwards, Harry W. "A Naval Lesson of the Korean Conflict." United States Naval Institute Proceedings 80 (December 1954) : 1337-1340.
Griffin, Harry K. "The Navy in Korean Waters." Army Information Digest 12 (1951): 12-22.
Kinney, Sheldon. "All Quiet at Wonsan." United States Naval Institute Proceedings 80 (August 1954): 858-867.
Patterson, Andrew, Jr. "Mining: A Naval Strategy." Naval War College Review 97 (May 1971): 52-66.
Phillips, Richard B. "The Siege of Wonsan." Army Information Digest 8 (November 1953): 39-47.
Rairden, P. W., Jr. "The Junior Officer in Mine Warfare." United States Naval Institute Proceedings 79 (September 1953) : 977-979.
Saar, C.W. "Offensive Mining as a Soviet Strategy." United States Naval Institute Proceedings 90 (August 1964) : 42-51.
121
APPENDIX A
UNITS ASSIGNED TO CTG 95.6 MINESWEEPING FORCE DURING THE KOREAN WAR
NAME DESIGNATION CLASS MINESWEEPER (AM)
Chief AM-315 AUK Competent AM-336 AUK Defense AM-317 AUK Devastator AM-318 AUK Dextrous AM-341 AUK Impeccable AM-320 AUK Incredible AM-249 ADMIRABLE Gladiator AM-319 AUK Mainstay AM-261 ADMIRABLE Murre let AM-372 AUK Pirate AM-275 ADMIRABLE Pledge AM-277 ADMIRABLE Ptarmigan AM-376 AUK Redstart AM-373 AUK Ruddy AM-380 AUK Shoveler AM-382 AUK Surfbird AM-383 AUK Swift AM-122 AUK Symbol AM-123 AUK Toucan AM-387 AUK Waxwing AM-389 AUK Zeal AM-131 AUK
AUXILIARY MINESWEEPER (AMS) Chatterer AMS-40 ALBATROSS Condor AMS-5 ALBATROSS Curlew AMS-8 ALBATROSS Firecrest AMS-10 ALBATROSS Gull AMS-16 ALBATROSS Heron AMS-18 ALBATROSS Kite AMS-22 ALBATROSS Magpie AMS-25 ALBATROSS Merganser AMS-26 ALBATROSS Mocking Bird AMS-27 ALBATROSS Osprey AMS-28 ALBATROSS Partridge AMS-31 ALBATROSS Pelican AMS-32 ALBATROSS Redhead AMS-34 ALBATROSS Swallow AMS-36 ALBATROSS Waxbill AMS-39 ALBATROSS
DESTROYER MINESWEEPER (DMS) Carmick DMS-33 ELLYSON Doyle DMS-34 ELLYSON Endicott DMS-35 ELLYSON Thompson DMS-38 ELLYSON
122
AUXILIARY SHIPS NET LAYING SHIP (AN)
Mulberry DEGAUSSING SHIP (ADG)
ADG-11 GASOLINE TANKER
Genesee HIGH SPEED TRANSPORT
Diachenko Horace A. Bass
SALVAGE SHIP (ARS) Bolster Conserver Current Deliverer Grapple Grasp Reclaimer Safeguard
FLEET OCEAN TUG (ATF) Abnaki Apache Arikara Chickasaw Hitchiti Moctobi Molal a Quapaw Sarsi Takelma Tawas a Tawakoni Ute Yuma
AN-27
AOG-8 (APD)
APD-213 APD-124
ARS-38 ARS-39 ARS-22 ARS-23 ARS-7 ARS-24 ARS-42 ARS-25
ATF-96 ATF-67 ATF-98 ATF-83 ATF-103 ATF-105 ATF-106 ATF-110 ATF-111 ATF-113 ATF-92 ATF-114 ATF-76 ATF-94
TREE
PATAPSCO
BOLSTER BOLSTER BOLSTER BOLSTER BOLSTER BOLSTER BOLSTER BOLSTER
ABNAKI ABNAKI ABNAKI ABNAKI ABNAKI ABNAKI ABNAKI ABNAKI ABNAKI ABNAKI ABNAKI ABNAKI ABNAKI ABNAKI
LANDING CRAFT/SHIP UTILITY (LCU/LSU) LCU-1124 LCU-1363
LANDING SHIP DOCK Cabildo Catamount Colonial Comstock Epping Forest Fort Marian Gunston Hall Tortuga Whetstone
LANDING SHIP TANK LST-692 LST-735 LST-772
(LSD)
(LST)
501-1465 501-1465
LSD-16 CABILDO LSD-17 CABILDO LSD-18 CABILDO LSD-19 CABILDO LSD-4 ASHLAND LSD-22 CABILDO LSD-5 ASHLAND LSD-32 CABILDO LSD-27 CABILDO
511-1152 511-1152 511-1152
123
SERIES SERIES
SERIES SERIES SERIES
LST-799 LST-802 LST-819 LST-855 LST-901 LST-975 LST-1077 LST-1138 LST-1141 SCAJAP LST-Q007 SCAJAP LST-Q008 SCAJAP LST-QO 12 SCAJAP LST-Q092
MISCELLANEOUS AUXILIARY (YAG) YAG-36 YAG-37 YAG-38
JAPANESE MINESWEEPERS MS01-17, 57, 81-86 MS18-30 MS31 Soei-Maru SS/MV MS32
511-1152 SERIES 511-1152 SERIES 511-1152 SERIES 511-1152 SERIES 511-1152 SERIES 511-1152 SERIES 511-1152 SERIES 511-1152 SERIES 511-1152 SERIES 511-1152 SERIES 511-1152 SERIES 511-1152 SERIES 511-1152 SERIES
GUINEA PIG SHIP LIBERTY SHIP LIBERTY SHIP LIBERTY SHIP
HEADQUARTERS SHIP
MS33-39, 41-42, 50, 54-56, 58-62, 66-72, 75, 77, 80 PS02, 04, 08 43
SOUTH KOREAN MINESWEEPERS (YMS) JMS-302 JMS-306 Kanggyong Kangjin Kangkae Kangnung Kimchon Kimhae Kuwalsan Kwangju Kyongju Ue Nan
LANDING SHIP INFANTRY, Chung Jin
LANDING SHIP SUPPORT, LSSL-107 LSSL-108 LSSL-109 LSSL-110
YMS-510 YMS-501 YMS-506 YMS-507 YMS-513 YMS-505 YMS-512 YMS-503 YMS-502 YMS-515
LARGE (LSIL) LSIL-105
LARGE (LSSL)
LANDING SHIP TANK (LST) An dong LST-803
LST-801 Chongho LST-805 LST-806 Ulsan LST-802
124
NOTE: Many of the auxiliary vessels were assigned for one mission only and so served for less than one month before being rotated out. The DMSs were paired up and transferred out to replace one another. LST-799 and LST-735 were also exchanged for one another regularly.
SOURCE: Cagle and Manson, Sea War in Korea, CINCPACLFT Interim Reports 1-6, and COMNAVFE Command and Historical Reports.
125
APPENDIX B
SHIP STATISTICS
MINESWEEPERS
AM AUK Class Minesweeper (AM): 890 tons, 215', 1-3", 2 to 4-40nun
AA, 3 to 5-20mm AA, 18kts., 105 crew.
ADMIRABLE Class Minesweeper (AM): 650 tons, 180', 1-3", 4-40nun AA, 15kts., 104 crew.
AMS ALBATROSS Class Auxiliary Minesweeper (AMS): 270 tons, 136',
1-3", 2-20nun AA, 15kts., 50 crew.
DMS ELLYSON Class Destroyer Minesweeper (DMS): 1630 tons, 341', 3-
5", 38 cal., 4-40nun AA, 3 to 5-2nun AA, 37kts., 250 crew.
MSBs: 30 tons, 57', 10knts., 6 crew.
AUXILIARY SHIPS
TREE Classs Net Laying Ship (AN): 560 tons, 146', 1-3"AA, 13kts., 48 crew.
PATAPSCO Class Gasoline Tanker (AOG): 1850 tons, 292', 4-3", 50 cal., 14 kts., 124 crew.
High Speed Transport (APD) : 1400 tons, 300', 1-5", 38 cal., 6-40mm AA, 23.6kts., 214 crew.
BOLSTER Class Salvage Ship (ARS) : 1360 tons, 207', 4-40nun AA, 14kts., 85 crew.
ABNAKI Class Fleet Ocean Tug (ATF) : 1235 tons, 195', 1-3", 4-40mm AA, 2-20mm AA, 16.5kts., 85 crew.
AMPHIBIOUS SHIPS
501-1465 SERIES Landing Craft Utility (LCU): 143 tons, 120', lOkts., 150 tons cargo capacity.
CABILDO Class Landing Ship Dock (LSD): 4032 tons, 454'' 1~5"' 38 cal., 12-40mm AA, 15.4kts., 240 crew, 14 LCMs carr1ed.
126
ASHLAND Class Landing Ship Dock (LSD) : 4500 tons, 454', 1-5", 4-40rnm AA, 16-20rnm AA, 17kts., 18LCMs carried.
511-1152 SERIES Landing Ship Tank (LST): 1653 tons, 316', 7-40rnm AA, 2-20rnm AA, 11kts., 211 crew.
JAPANESE MINESWEEPERS
MS01-17, 57, 81-86: 135 tons, 11kts., unarmed wooden exauxiliary submarine chaser.
Minesweeper Headquarters Ship: MS31-6,888 tons, 13kts. MS32-2,850 tons, 11.5kts., ex-wartime 2TM tanker used as a guinea pig.
MS33-39, 41-42, 50, 54-56, 58-62, 66-72, 75, 77, 80: varyig tonnages up to 350 tons, auxiliary minesweepers, MS62 (SCAP Y071) mother ship to MSs.
PS02, 04, 08, 43: destrucotr ships following the minesweepers to sink swept mines. PS43 barracks ship in Korea and Japan.
ROKN MINESWEEPERS
ROKN YMS: 270 tons, 136', 1-3", 50 cal., 2-20mm AA, 15kts., 50 crew, wooden ex-U.S. auxiliary minesweepers.
ROKN LST: ex-U.S. LSTs.
Source: Raymond V.B. Blackman, ed. Jane's Fighting Ships, 1949-1954.
127
APPENDIX C
TASK ORGANIZATIONS FOR THE INCHON, WONSAN, AND
CHINNAMPO SWEEPS
INCHON Screening and Protective Group, Captain Richard T. Spofford
Rowan Southerland 2DD Bayonne Newport Evansville HMS Mounts Bay HMS Whitesand Bay HMNZS Tutira FS La Grandiere 7PF
MINRON 3, Captain Spofford Pledge lAM Kite Mocking Bird Partridge Osprey Chatterer Redhead
WON SAN
6AMS
Minesweeping and Protective Group, Captain Richard T. Spofford Collet lDD Diachenko lAPD Doyle Endicott 2DMS Pledge Incredible 2AM Kite Merganser Mocking Bird Osprey Partridge (assigned later for Iwon) Redhead Chatterer 7AMS HMS Mounts Bav HMNZS Pukaki HMNZS Tutira FS La Grandiere 4PF 8 Japanese minesweepers 4 Japanese mine destruction and danning vessels 1 ROK FS Plus other units assigned
128
CHINNAMPO Task Element 95.69,
Horace A. Bass Bolster Thompson Carmick
Commander Stephen M. Archer 1APD 1ARS
2DMS Gull Pelican Swallow 3AMS Catamount 1LSD MSBs 12LCVP work boats 2 40' motor launches LST Q007 1LST Japanese Minesweepers
PS-56 PS-62 2PS MS-03 MS-06 MS-08 MS-09 MS-10 MS-12 MS-13 MS-15 MS-21 MS-22 MS-23 MS-57 12MS
ROKN Minesweepers JMS-306 YMS-502 YMS-503 YMS-513 4ROKN YMS
Source: CINCPACFLT Interim Report 1, 5: 740-745; Karig, 357-358.
129
APPENDIX D
AVAILABLE MINESWEEPERS IN THE FAR EAST
Country Australia Canada
Number 32
French Indochina Great Britain
India Indonesia Nationalist China
Netherlands Philippine Republic South Korea Thailand
U.S.S.R.
9 22
7
6 4
lSAM 8AMS 9 2AM
lOYMS lAM 3AMS 3CMC
33AM SOAMS
(ex-US)
TOTAL 213
Location
6 Singapore 1 Hong Kong
Formosa
Indonesia
Petropavlovsk Kosakov Olga Sovetskaya Vladivostok Nadhodka
Status in reserve 4 operational operational activating unknown 4 operational lack training operational operational operational poor condition no gear unknown unknown unknown operational operational
Source: CINCPACFLT Interim Report 1, 6: 1094.
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APPENDIX E
MINES SWEPT
DISPOSITION OF MINES ENCOUNTERED BY MONTHS MONTH SWEPT SWEPT FLOATER FLOATER RECOVERED TOTAL
DEST. NOT SIGHTED SIGHTED DEST. DEST. NOT DEST.
1950 August NA NA NA NA NA 4 1951 September NA NA NA NA NA 216 November-December NA NA NA NA NA 173 1952 January 1 0 13 1 0 15 February 4 0 15 7 1 27 March 40 5 24 2 5 76 April 15 1 13 0 4 33 May 15 5 7 5 1 33 June 7 0 3 0 3 13
July NA NA NA NA NA 6
August NA NA NA NA NA 54
September NA NA NA NA NA 32
October NA NA NA NA NA 10
November NA NA NA NA NA 17
December NA NA NA NA NA 6
1953 January NA NA NA NA NA 13
February 3 0 10 0 0 13
March 1 0 9 0 1 11
April 1 1 19 2 0 23
May 3 0 11 0 0 14
June 1 1 15 1 0 18
July 1 0 13 0 0 14
TOTAL 92 13 152 18 15 1088
MINE TYPES ENCOUNTERED BY MONTHS MONTH MKB M26 MY aM PLT UNIDENT. TOTAL
1952 15 January 5 6 0 0 4
February 14 10 0 0 3 27
March 16 9 46 0 5 76
April 16 11 2 0 4 33
May 4 17 5 0 7 33
June 0 5 8 0 0 13
July 2 1 2 1 0 6
August 8 22 8 0 16 54
September 4 19 1 2 6 32
October 5 1 1 3 0 10
131
MONTH November December 1953 January February March April May June July TOTAL
MKB 2 0
3 3 2 1 3 7 5
100
M26 14
2
4 3 2
15 7 5 5
158
MY aM 0 4
3 4 6 2 0 4 3
99
DISPOSITION OF MINES ENCOUNTERED TYPES SWEPT SWEPT FLOATER
DEST. NOT SIGHTED DEST. DEST.
January-June, 1952 MKB 23 M26 17 MYaM 41 Unident. 1 July, 1952-January, MKB 1 M26 13 MYaM 0 PLT 6 Unident. 3 February-July, 1953 MKB 0 M26 7 MYaM 0 PLT 0 Unident. 2 TOTAL 114
0 6 2 3 1953 0 0 0 0 0
1 0 0 1 1
14
27 29 11
8
21 50 17
0 14
20 30 17
0 10
254
PLT 0 0
0 0 0 1 0 0 0 7
UNIDENT. 1 0
3 3 1 4 4 2 1
64
FLOATER RECOVERED SIGHTED NOT DEST.
1 4 2 4 1 6
11 0
1 1 0 0 0 2 0 0 9 0
0 0 0 0 1 1 0 0 2 0
28 18
TOTAL 17
6
13 13 11 23 14 18 14
428
TOTAL
55 58 61 23
24 63 19
6 26
21 37 19
1 15
428
Note: The tables are incomplete as some documents pertaining to the Korean War are still classified. Many of the available documents differed on the number of mines swept, even conflicting with the text attached to the documents. Emphasis has been placed on the CINCPACFLT Interim Evaluation Reports as they are the most precise.
Source: CINCPACFLT InterimReport 2, 11: 1751-1763, 1769-1773, CINCPACFLT Interim Report 4, 8: 3 9-4 0, CINCPACFLT Interim Report 5, 7: 50, CINCPACFLT Interim Report 6, 8: 45, COMNAVFE Command and Historical Reports.
132
NAME
Magpie (AMS-25) Pirate (AM-275) Pledge (AM-277) Japanese MS-14 ROKN YMS-516 LT-236 Partridge (AMS-31) ROKN JMS-306 ROKN PC-704 Sarsi (ATF-111)
NAME Brush (DD-745) ROKN YMS-509 Mansfield (DD-728) ROKN YMS-504 ROKN BM FS-673 Suzen-Maru (S-152) EG Small (DD-838) Kite (AMS-22)
APPENDIX F
UNITED NATIONS SHIPS SUNK AND DAMAGED IN KOREAN WATERS
SHIPS SUNK BY MINES
DATE
September 29, 1950 October 12, 1950 October 12, 1950 October 17, 1950 October 19, 1950 November 15, 1950 February 2, 1951 May 5, 1951 December 26, 1951 August 27, 1952
NOTES
12WIA, 21MIA Wonsan Wonsan Wonsan Wonsan, 4KIA, 13MIA Wonsan, buoy 3 4KIA, 7WIA, 4MIA Chinnampo, 6KIA, 18WIA Wonsan, all hands lost 2KIA, 4WIA, 3MIA
SHIPS DAMAGED BY MINES
DATE September 26, 1950 September 28, 1950 September 30, 1950 October 1, 1950 October 18, 1950 December 6, 1950 October 7, 1951 November 9, 1951
NOTES Tanchon, 9KIA, 10WIA 1KIA, 5WIA, 25MIA 48WIA, 5MIA Mokpo Wonsan Hungnam Hungnam, 9KIA, 8WIA Won san
MINESWEEPERS DAMAGED IN KOREA DUE TO OTHER CAUSES (SHORE BATTERY FIRE UNLESS SPECIFIED DIFFERENTLY)
NAME
ROKN YMS-510 Carmick (DMS-33) Thompson (DMS-38) Dextrous (AM-341) Redstart (AM-373) Heron (AMS-18) Firecrest (AMS-10) Osprey (AMS-28) Dextrous (AM-341) Endicott (DMS-35) ROKN JMS-301
DATE
March 16, 1951 March 27, 1951 June 14, 1951 August 11, 1951 September 10, 1951 September 10, 1951 October 5, 1951 October 29, 1951 January 11, 1952 February 4, 1952 March 1, 1952
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NOTES
Wonsan, 3KIA, 8WIA Collision, Songjin 3KIA, 4WIA superficial damage minor damage superficial damage hull damage 1WIA Wonsan, 3WIA Songjin, minor damage sunwi-do, 1KIA
Endicott (DMS-35) Endicott (DMS-35) Osprey (AMS-28) Murrelet (AM-372) Swallow (AMS-36) Firecrest (AMS-10) Thompson (DMS-38) Competent (AM-336) Osprey (AMS-28) Kite (AMS-22) Thompson (DMS-38) ROKN YMS-506 ROKN YMS-510 ~ (AMS-16) ROKN YMS-506 Swift (AM-122)
April 7, 1952 April 19, 1952 April 24, 1952 May 26, 1952 May 26, 1952 May 29, 1952 August 20, 1952 August 27, 1952 October 13, 1952 November 19, 1952 November 20, 1952 March 9, 1953 March 9, 1953 March 16, 1953 May 15, 1953 May 29, 1953
Chongjin Chongjin, minor damage Songjin, minor damage Songjin, 1KIA, 2WIA Songjin, slight damage minor damage Songjin, 3KIA, 8WIA minor damage Kojo, 4WIA, near miss Wonsan, 5WIA Wonsan, hull damage no details given no details given no details given no details given no details given
Source: CINCPACFLT Interim Report 1, 6: 1141, CINCPACFLT Interim Report 3, 1: 33-35, CINCPACFLT Interim Report 4, 1: 23-24, CINCPACFLT Interim Report 5, 7: 22, CINCPACFLT Interim Report 6, 1: 30-35., COMNAVFE, Command and Historical Report, September-November 1950, chapter 2, 13.
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