EFFECTS OF VESSEL EFFECTS OF VESSEL LENGTH AND DESIGN LENGTH AND DESIGN ON MOTIONS, SAFETY ON MOTIONS, SAFETY AND DOWNTIME.AND DOWNTIME.

DON BASS (MUN)DON BASS (MUN)

Wave Periods on NE Coast

Wave Heights on NE Coast

Percentage 0ccurrence of Percentage 0ccurrence of Waves over 3 m. by Waves over 3 m. by MonthMonth

Percentage of Waves over 3 m in Height by Month

0

10

20

30

40

50

60

70

80

90

july august september october november december

Month (integer)

per

cen

tag

e ex

ceed

ance

lev

el

Simulations using Simulations using MOTSIMMOTSIM

3 m significant wave height for various wave 3 m significant wave height for various wave periods. Typical to severe Fall weather periods. Typical to severe Fall weather conditions. Speed 5 knots in head seas.conditions. Speed 5 knots in head seas.

Boats used in the simulationsBoats used in the simulations 65 foot fiberglass boat with 26 foot beam65 foot fiberglass boat with 26 foot beam 90 foot fiberglass boat with 19 foot beam (scaled 90 foot fiberglass boat with 19 foot beam (scaled

version of the above 65 foot vessel)version of the above 65 foot vessel) 75 foot steel boat 22 foot beam (extended 65 footer)75 foot steel boat 22 foot beam (extended 65 footer) 100 foot steel with 24 foot beam (extended 65 100 foot steel with 24 foot beam (extended 65

footer)footer) 65 foot aluminum catamaran fishing boat65 foot aluminum catamaran fishing boat

65 Foot Fibre Glass Boat

90 foot Fibre Glass Boat

75 foot Steel Boat

100 Foot Steel Boat

Predictions of Pitch Motions Predictions of Pitch Motions of the Lauzier at 10 Knotsof the Lauzier at 10 Knots

Pitch for November Trials at 10 kt, Comparisons for Different Spectra Observed

during Sea Trial

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

-50 0 50 100 150 200Heading (degrees)

Pit

ch (

deg

rees

)

Sea Trial

motsim,measured directional

experiment

Pitch Motion Predictions Pitch Motion Predictions of the Lauzier at 6 knotsof the Lauzier at 6 knots

Pitch for November Trials at 6 kts, Comparisons for Different Spectra Observed during Sea Trial

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

-50 0 50 100 150 200Heading (degrees)

Pit

ch

(d

eg

ree

s)

SeaTrial

motsim, measured directional

experiment

Pitch Comparisons in 3m Head Waves

0

2

4

6

8

10

12

14

16

18

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5

Wave Frequency

Pit

ch

(d

eg

ree

s)

65 ft FG

90 ft FG

100 ft steel

65 ft Cat

75 ft steel

Pitch Motions In 3 M Head Seas

Heave Comparisons in 3m Head Waves

0

0.5

1

1.5

2

2.5

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5

Wave Frequency

Hea

ve (m

)

65 ft FG

90 ft FG

100 ft steel

65 ft Cat

75 ft steel

Heave Motions In 3 M Head Seas

Motion Induced Motion Induced InterruptsInterrupts

Measure of the ability of someone at Measure of the ability of someone at some location on a moving platform to some location on a moving platform to complete certain tasks.complete certain tasks.

Measure of the likelihood of an accident Measure of the likelihood of an accident occurring due to slipping or tipping.occurring due to slipping or tipping.

Number of “Loss-of-Balance Incidents” Number of “Loss-of-Balance Incidents” per minuteper minute

Formulae for Motion- Induced Interrupts

  MII RISK LEVELS    

           

Risk Level   MII's per Minute

           

1 = Possible   0.1  

2 = Probable   0.5  

3 = Serious   1.5  

4 = Severe   3.0  

5 = Extreme   5.0  

MII for 65 ft, 75 ft ,90 ft and 100ft Vessels in 3 m Head Seas averaged over points in middle third of the Main Deck

Motion Induced Interrupts Comparisons in 3m Head Waves

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5

Wave Frequency

MII

/min

ute

65 ft FG

90 ft FG

100 ft steel

65 ft Cat

75 ft steel

Loss of Fishing Days Due Loss of Fishing Days Due to Weatherto Weather

Based on the assumption that fishing activity Based on the assumption that fishing activity becomes difficult or dangerous if MII per becomes difficult or dangerous if MII per minute exceeds 1.5, the 65-footer would need minute exceeds 1.5, the 65-footer would need to avoid 3 m seas and the 100 foot vessel, 4 m to avoid 3 m seas and the 100 foot vessel, 4 m seas.seas.

Taking the average wave height over a 5-day Taking the average wave height over a 5-day period we can determine how many 5-day trips period we can determine how many 5-day trips could be completed with an average wave could be completed with an average wave height below either 3 m or 4 m.height below either 3 m or 4 m.

Based on wave statistics off the NE coast over Based on wave statistics off the NE coast over the past 10 years.the past 10 years.

Possible Number of Fishing Possible Number of Fishing Trips per month over a 10 Trips per month over a 10 year Period for the 65 foot year Period for the 65 foot fishing vessel.fishing vessel.

Number of Possible 5 Day Trips per Month by Year for a 65 foot Fishing Vessel.

0

1

2

3

4

5

6

7

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

Nu

mb

er

of

5 d

ay

tri

ps

August

September

October

November

December

Number of Possible Trips for Number of Possible Trips for 65 and 100 footers (10 year 65 and 100 footers (10 year averages)averages)

Number of Possible 5 Day Trips per Month Based on 10 Year Averages of Wave Data for 65 foot and 100 foot

Fishing Vessels

0

1

2

3

4

5

6

7

august September October November December

Nu

mb

er

fo T

rip

s

65 footer

100 footer

CONCLUSIONSCONCLUSIONS

Difficult to come up with precise quantitative Difficult to come up with precise quantitative data on the number of fishing days lost due to data on the number of fishing days lost due to weather related factors.weather related factors.

Rough estimate based on MII approach shows Rough estimate based on MII approach shows considerable down time in the Fall for vessels considerable down time in the Fall for vessels 65 foot and under.65 foot and under.

It is clear that vessel length and design play It is clear that vessel length and design play important roles in determining that number.important roles in determining that number.