Search Patterns Search Patterns -- Rev: Nov 05 Boat Forces Center Coxswain “C” School

Search Patterns

Search Patterns -- Rev: Nov 05

Boat Forces Center Coxswain “C” School

Objectives

Given the following instruction state common terms used in Search and Rescue

Given basic navigation tools plot and execute both precision and drifting patterns

References

National Search and Rescue Manual Vol I & II COMDINST M16120.5 series

U.S. Coast Guard Addendum to the National Search and Rescue Supplement COMDINST M16130.2 series

Boat Crew Seamanship manual COMDINST M16114.5 series

CG Boat Operations and Training Manual VOL I & II COMDINST M 16114.32 series

Value

The boat Coxswain must be able to execute the search pattern correctly, so that lives and property in distress have the best possible chance for survival

Coxswain Responsibility

Keep crew alert and attentive

Execute the search pattern correctly

SOMEONE'S LIFE MAY DEPEND ON IT

Search Planning

Is necessary when the location of a distress object is not known, or time has passed since the objects position was last known

SAR Planning

Where does SAR planning come from?

The Coast Guard Addendum to the National Search and Rescue Supplement COMDTINST M16130.2(series)

SAR Addendum

The primary search planning & rescue operations guidance and policy manual

Pattern Nomenclature

Datum

The most probable location of a search

object corrected for movement over time


Explanation of movement:

To locate datum, Two major forces need to

be considered:

Total Water Current

Leeway


Total water current (TWC)

•The sum of all water currents that might be The sum of all water currents that might be acting upon a search object in any given acting upon a search object in any given localitylocality

Sea Current

Wind Current

Reversing Tidal Current

River Current

Lake Current

Surf & Rip Current

The best information on TWC is obtained from a Datum Marker Buoy.


Leeway:

The movement through the water caused by winds blowing against the exposed surfaces of the search object. The more exposed area the object has the greater the wind force on the object


Search Leg:

The track line of the SRU involved in a search pattern, or the long leg along the track of a parallel or creeping line search


Cross Leg:

The connection between search legs of a parallel or creeping line search pattern


Sweep Width:

The corrected distance a SRU should be able to visually detect the search object on either side of the search leg


Track Spacing:

The distance between adjacent parallel legs

With the exception of the Sector search which will have a radius


Major Axis:

A bearing line used for the orientation of a rectangular search area from the center


Minor Axis:

A bearing line perpendicular to the major axis


Commence Search Point (CSP)

The location in the search area that the SRU starts the search pattern


Initial Response (PIW)

When searching for people in the water start a Sector Search ASAP:

• Speed 6 knots

• Track spacing: .1 NM

• 1 minute search legs


Search Area:

• The area most likely to contain the search object.

• Start with determining datum

• There are 7 different methods

Corner Method

BLDG

37º19’00”N076º15’00”W

37º20’26”N076º13’57”W

37º18’17”N076º13’19”W

37º19’36”N076º12’05”W

Corner Method:In this method the latitude and longitude (or geographic features) of each corner of the search area are given

Track line Method

BLDG

37º21’45”N076º14’22”W

37º20’44”N076º12’06”W

37º18’35”N076º12’15”W

Trackline Method:The latitude and longitude of the departure point, turns and destination are given with a specific width along the track

Center Point CircularBLDG

37º21’00”N076º13’38”W

0.75 NMradius

Center Point, Circular Area:The latitude and longitude of the center point are given with a radius

Center Point

BLDG

37º21’00”N076º13’38”W

Center Point, Rectangular or Square Area:The latitude and longitude of the center point are given with the direction of themajor axis and the length and width of the area

Range and Bearing

BLDG

Range and Bearing to Center Point:The center point may also be designated bya range and bearing from a geographic landmark

140ºT2 NM

Landmark Boundary

Landmark Boundary:Two or more landmarks are given asboundaries of the search area along a shoreline

BLDG

Point Comfort

3 NM

Lat/Long Boundary

BLDG

Latitude/Longitude Boundary:The sides of the search area are oriented North-Southand East-West and the latitude and longitude of thesides are given

37º21’00”N

076º11’30”W

37º18’00”N

076º14’30”W

Pattern Designations

First Letter Designates Pattern:

• “P” for Parallel

• “C” for Creeping Line

• “S” for Square

• “V” for Sector

• “T” for Track line

• “B” for Barrier

Pattern Designations

Second Letter Designates Number of SRU’s:

– “S” for Single Search Unit– “M” for Multiple Search Units

Third Letter for Supplementary Information:

– “R” for Radar Coordination or Return– “N” for Non-Return to Starting Point

Labeling Patterns

• Plotted in true

• Courses labeled in true and compass

• Turns labeled with DR’s and DR times

“PS” Pattern

Parallel track search, Single unit use:

– Large area

– Position of search object approximate

– Uniform coverage desired

– Search leg parallel to major axis

Plotting a “PS”

Search Area

1 ½ 0 1 2 3 4

N (True)

•Determine Search Area

Plotting a “PS”

Search Area

1 ½ 0 1 2 3 4

Measure ½ track spacing in from the cornersMeasure ½ track spacing in from the corners

Plotting a “PS”

1 ½ 0 1 2 3 4

Connect the marks to make the patterns size Connect the marks to make the patterns size

Plotting a “PS”

1 ½ 0 1 2 3 4

CSP

Mark CSP, mark full track spacing and lay out cross legsMark CSP, mark full track spacing and lay out cross legs

Plotting a “PS”

Lay out search legs, and erase every other cross leg

1 ½ 0 1 2 3 4

CSP

Plotting a “PS”

Label a minimum of three legs a DR at all turns

1 ½ 0 1 2 3 4

CSPC- ºT/ ºCD- NM S- KN

C- ºT/ ºCD- NM

C-

ºT

ºCD

-

N

M

“CS” Pattern

CREEPING LINE SEARCH, SINGLE UNITUSE:

– LARGE AREA

– UNIFORM COVERAGE DESIRED

– POSITION OF SEARCH OBJECT IS BELIEVED TO BE ON ONE END OF SEARCH AREA

– SEARCH LEGS PARALLEL TO MINOR AXIS

Plotting a “CS”

Search Area

1 ½ 0 1 2 3 4

N (True)

Plotting a “CS”

Search Area

1 ½ 0 1 2 3 4

N (True)

Measure ½ track spacing in from the cornersMeasure ½ track spacing in from the corners

Plotting a “CS”

1 ½ 0 1 2 3 4

Connect the marks to make the pattern sizeConnect the marks to make the pattern size

Plotting a “CS”

1 ½ 0 1 2 3 4

CSP

Mark CSP, measure full track spacing and lay out cross Mark CSP, measure full track spacing and lay out cross legslegs

Plotting a “CS”

1 ½ 0 1 2 3 4

CSP

Lay out search legs and erase every other cross legLay out search legs and erase every other cross leg

Plotting a “CS”

Label a minimum of three legs and a DR at all turns

1 ½ 0 1 2 3 4

CSP

C-

ºT/

ºC

D-

NM

S-

K

N

C-

ºT/

ºC

D-

NM

C- ºT ºCD- NM

“VS” Pattern

SECTOR SEARCH, SINGLE UNIT USE:

– RELIABLE POSITION OF SEARCH OBJECT

– CONCENTRATED AT DATUM

– DATUM AT CENTER

– STARTS AND ENDS AT DATUM

– ALL TURNS ARE 120º TO THE RIGHT

– 1ST LEG IN DIRECTION OF DRIFT

Plotting a “VS” Pattern

Plot datum and arc a full track spacing around it

1 ½ 0 1 2 3 4


Lay down first track line, either 000 T or the direction of drift originating from datum

1 ½ 0 1 2 3 4

Datum


Mark track spacing on either side of the line top and bottom

1 ½ 0 1 2 3 4

Datum


Lay out the remaining track lines by connecting the marks

1 ½ 0 1 2 3 4

Datum


Label three legs minimum

1 ½ 0 1 2 3 4

Datum

C- ºT/ ºC

D- NM

C-

º

T/

º

CD

-

NM

S-

KN

C- ºT

/ º

C

D- N

M

“SS” Pattern

EXPANDING SQUARE SEARCH, SINGLE UNIT USE:

– SMALL AREA

– FIRST SEARCH LEG IS EITHER DIRECTION OF DRIFT OR TRUE NORTH

– ALL TURNS ARE 90º TO THE RIGHT

– TRACK SPACING DETERMINES 1ST AND 2ND LEG THEN ADD ONE TRACK SPACING EVERY OTHER LEG

“Plotting a SS” Pattern

Plot datum and mark a full track spacing around it

1 ½ 0 1 2 3 4

“Plotting a SS” Pattern

Lay down first search leg, either 000ºT or direction of drift, originating from datum

1 ½ 0 1 2 3 4

CSP

Plotting a “SS” Pattern

Lay down search leg #2, 90º to the right of #1 for the distance of 1 track spacing

1 ½ 0 1 2 3 4

CSP


Add one track spacing to determine length of search leg for search legs #3 and #4, plot #3 and #4

1 ½ 0 1 2 3 4

CSP


Repeat for number of legs required

1 ½ 0 1 2 3 4

CSP


Label all legs

CSP

1 ½ 0 1 2 3 4

C- ºT/ ºCD- NM

C-

ºT/

ºC

D-

NM

C- ºT

/ ºCD

- NM

C

-

ºT

/

º

CD

-

N

M

C- ºT/ ºCD- NM

C- ºT/ ºCD- NM

C- ºT/ ºCD- NM

C- ºT

/ ºCD

- NM

“TSN” Pattern

TRACKLINE SEARCH, SINGLE UNIT,NON-

RETURN USE:

– ONLY INFORMATION AVAILABLE IS THE INTENDED TRACK OF TARGET

– START SEARCH AT CSP AND SEARCH THE INTENDED TRACKLINE OF THE SEARCH OBJECT

“TSR” Pattern

TRACKLINE SEARCH, SINGLE UNIT,

RETURN USE:

– ONLY INFORMATION AVAILABLE IS THE INTENDED TRACK OF TARGET

– CSP IS OFFSET 1/2 TRACK SPACING FROM SEARCH OBJECTS INTENDED TRACKLINE

– SRU SEARCHES ONE SIDE THEN THE OTHER OF THE SEARCH OBJECT’S INTENDED TRACK

Plotting a “TSR” Pattern

Using the target's intended track line, plot positions along the track at the origin of your search and any turns

1 ½ 0 1 2 3 4


Using 1/2 track spacing, arc a circle around each plotted position and at the first position, plot a line perpendicular to the intended track line

1 ½ 0 1 2 3 4


CSP will be located at one end of the perpendicular line, the finish is the other. From CSP lay down the search legs (note the turn)

1 ½ 0 1 2 3 4

CSP


Label all legs

C- ºT/

ºC

D- NM S

- KN

C- ºT/ ºCD- NM

C- ºT/ ºCD- NM

C- ºT/

ºC

D- NM

1 ½ 0 1 2 3 4

CSP

C-

º

T

ºC

D-

N

M

Review

What manual is the primary manual used for

search planning and rescue operations?

Coast Guard Addendum to the National SAR Manual

Review

What is the definition of datum?

The most probable location of a search object corrected for movement over time

Review

What is the definition of a search leg?

The track line of the SRU unit

OR

The long leg along the track of a parallel or creeping line search

Review

What is the definition of sweep width?

The distance an SRU should be able to detect the search object on either side of the leg

Review

What is CSP?

Commence Search Point:The location at which the SRU starts the search pattern

Review

What search pattern is a “PS”?

Parallel Search patternSingle Unit

Review

What search pattern is a “SS”?

Expanding Square Search patternSingle Unit

Review

What search pattern is a “TSR”?

Track Line Search patternSingle UnitReturn

Questions??

Documents

Search Patterns Search Patterns -- Rev: Nov 05 Boat Forces Center Coxswain “C” School