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Fish Safe1100 – 1200 West 73rd AvenueVancouver, British ColumbiaCanada V6P 6G5

604.261.9700

604.264.6133

fishsafe@telus.net

fishsafebc.com

Stability… an overviewWhy Fishing Vessels Float… why the goldsmith was beheadedFishing Vessel Stability… talking the talk Inclining Experiment and Stability BookHow Fishing Vessel Stability is Compromised… the good, the bad and the uglyWhat is the “One”… operating practices and stability Lessons LearnedAppendix: Regulations

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Table of Contents

Phone:

Fax:

E-mail:

www.

Acknowledgements

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From my perspective, the FISH SAFE Stability Education Program has been 30 years in themaking. Back in March 1975, it was the loss of 10 vessels in one herring season, includingmy father’s fishing vessel the Bravado off the BC coast, that raised many questions aboutwhat contributes to a capsizing. Are they operational issues?\ Structural issues? Both?That same year, a special enquiry into vessel capsizings identified vessel stability as a keycontributing factor and recommended a national program for stability education.

The Fish Safe Stability Education program is designed for fishermen and their unique oper-ating conditions and we hope it will provide answers and practical knowledge on stability.This handbook is only one component of this long-awaited education program developed toanswer questions, limit the number of capsizings and save lives at sea.

We would like to thank all those who assisted in developing this program by providingfunding and their expertise.Funding Assistance:Transport CanadaWorkSafeBCBC Seafood AllianceTechnical Expertise:Marine Action GroupMerlion Marine Services Inc.Larry BensonRobert Allan Ltd.Grant BrandlmayrBrian MoseResponse ProductionsFISH SAFE Advisory CommitteeFISH SAFE Course ParticipantsDesign and Production:Insight ProductionsAllsorts Design GroupAuthor:Barbara Howe, Quinte Marine Services Ltd.

Gina Johansen, Fishing Industry Safety Coordinator, Fish Safe

All rights reserved. This publication may not be copied, reproduced or transmitted in whole or in part without theprior written permission of Fish Safe.

“They that go downto the sea in ships,that do business ingreat waters….” Psalm 107:23

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Stability is a vessel’s ability to return to the upright whenheeled by external forces such as wind and waves.Regulatory agencies like Transport Canada determinestability criteria based on what has been shown to work.Naval architects use that criteria to design vessels thatwill have adequate stability throughout all anticipatedfishing conditions.

Your business is to understand the basic principles ofstability and make them central to your every day realitywhen making any decision that affects your vessel’soperations. Stable vessels don’t capsize.

When a fishing vessel capsizes the Transportation SafetyBoard investigates and writes a report that includescauses, findings and recommendations. A report from2001 indicates many investigations have revealed thatfishing vessel operators do not have an appreciation forthe factors affecting the stability of their vessels,particularly those factors which can be significantly influenced by their operating practices. (TSB Report No. M01W0253)

A recent TSB Report also suggests that a “true safetyculture” in the fishing industry can reduce the number of vessel incidents. Developing a safety culture includesstability education, risk awareness and understandingthat with every incident there is a lesson to be learned.Transport Canada, educators, fishing associations, fish-ermen and their families need to coordinate, cooperateand converge in the effort to promote a safety culture.

Fishing Vessel Stability – Make it Your Bussinesspresents fundamental principles of stability that willinform your fishing operations and ensure that your vesselalways has adequate stability. Lessons learned speakthroughout the Stability Handbook. If we listen, unnecessary loss and tragedy can be prevented.

Stability... an overview

“Unsafe practices are not carried out with the intention ofjeopardizing the safety of the vessel and crew. Rather theyare carried out by individuals who mean to operate theirvessels in a safe manner but who, for a number of reasons,do not fully appreciate the risks associated with suchpractices.” (TSB Report No. M02W0147)

Stability: a vessel’sability to returnto the uprightwhen heeled byexternal forces.

Culture: thepredominatingattitudes, sharedbeliefs and behaviour thatcharacterize thefunctioning ofa group ororganization.

4

Write down one question you have about fishing vesselstability.

What do you think a safety culture means? Do you thinkthat commercial fishing can achieve a safety culture withshared beliefs about safety?

If you have ever had a “near miss” involving vesselstability, what were the events that occurred?

Do you think vessel stability is a shared responsibilitybetween the owner, skipper and crew? Why?

Do you believe a serious marine incident will neverhappen to you? Why or why not?

What do you think the most important thing is thatfishermen need to know about stability?

Do you fully understand the stability characteristics ofyour fishing vessel? Explain your answer.

If you were to give another fisherman some advice aboutstability, what would you offer?

Would you feel comfortable giving your crew a stabilitybriefing? Or, if you are a crew member, are you comfort-able asking your skipper questions about stability?

With regard to stability, what do you think is moreimportant, the stability principles and the vessel, or theoperating practices during fishing and traveling?

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Questions for discussion

Lower a fishing vessel that weighs ten tonnes into atank of water as shown in the picture below. If an openvalve is arranged as illustrated, the water displaced canbe collected in a container and weighed. It will weighten tonnes which is the weight of the fishing vessel.This what the term displacement means – a vessel willdisplace a weight of the liquid it is floating in equal toits own weight.

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Why Fishing Vessels Float... why the goldsmith was beheaded

10 Tonnes

10Tonnes

The easy answer to “why do fishing vessels float?” is“because they don’t leak or have a hole in them”.Although this is true, Archimedes – the guy who whiletaking a bath exclaimed eureka - gave us a more detailedexplanation known as Archimedes’ Principle.

If you take a solid piece of metal and drop it into water, itwill sink to the bottom. However, take the same piece ofmetal, flatten it and form it into the shape of a ship sothat the volume it occupies is sufficiently increased, itwill float. The same weight of metal when formed into aship shape will put aside or displace a greater volume ofwater. This is called volume of displacement.

Talk the Talk Gross tonnageNet tonnageLightship displacementDeadweightDisplacementFreeboardDraftDraft marksMean draftReserve buoyancyDensityArchimedes’ PrincipleBeheaded

The volume of the liquid displaced will beequal to the vessel’s underwater volume.

Note: Stability books can include metric or imperial units.You will find both used in this handbook.

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20 Tonnes

30 Tonnes

10Tonnes

2 Tonnes

12 Tonnes

10Tonnes

Why Was the Goldsmith Beheaded?Archimedes was on retainer by King Heiro of Syracuse(around 250 BC). Heiro had given the goldsmith the exactamount of gold he wanted in a new crown. After the crownwas made the king suspected that it might not have as muchgold in it as it was supposed to. So the king summonedArchimedes to verify his suspicions. Archimedes figured thata gold crown should displace a certain amount of water.

Archimedes plopped the king’s new crown into water anddetermined that the crown displaced less water than the sameweight of gold should have displaced. It displaced less waterbecause the gold had been mixed with silver which is lessdense revealing that the crown was not pure gold and thegoldsmith was perhaps trying to fiddle the deal with the kingto advance his own pocket.

The goldsmith was immediately beheaded.

Add 30 tonnes of fish. The vessel will sink deeper tryingto displace 40 tonnes of water. However the entirevolume of the vessel cannot match a volume displacing40 tonnes of water, and will sink – the vessel’s ownweight and catch included cannot exceed 20 tonnes.

Add two tonnes of fish to the vessel. Then exactly twotonnes more water would be displaced for a total of 12tonnes. When weight is loaded onto a vessel both thevolume of displacement and the displacement weight areincreased.

Freeboard

Draft

Reserve BuoyancyDeck

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To Summarize Archimedes’ Principle:A vessel displaces a volume of liquid equal to its underwater volume.A vessel displaces its own weight of the water it isfloating in.If a vessel displaces its own weight before displacingits underwater volume, it will float.

The volume of a fishing vessel up to the waterline is thebuoyant volume. Reserve buoyancy is the volume of thevessel’s hull above the waterline to the upper mostwatertight deck. The freeboard of a fishing vessel is thedistance from the upper most watertight deck to thewaterline. The amount of freeboard indicates how much reserve buoyancy remains.

A vessel’s draft is the distance from the keel up tothe waterline in any condition of load. Some largerfishing vessels have draft marks on the hull, for-ward and aft. Draft marks are read from the bot-tom of the numeral, and the numerals are 6 incheshigh (10 centimetres if metric drafts are given).Mean draft is the total of the draft forward anddraft aft divided by two.

•

•

•

Draft For’d

Trimmed by the Head (For’d)

Draft Aft

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Trim is the difference between the forward draft and the aft draft. If the vessel has agreater draft forward it is trimmed by the head. If the greater draft is at the stern thevessel is trimmed by the stern. If the drafts are the same forward and aft the vesselis on an even keel.

Trimmed by the Stern (Aft)

Draft For’dDraft Aft

If a vessel has a forward draft of 4 feet and the draft aft is 6 feet it is trimmed 2 feetby the stern.

Relative density is defined as mass per unit volume. It is the comparative ratio ofthe weight of a substance shown against the weight of fresh water when bothweights occupy the same volume.

6 ins.

6 ins.

Draft 7 feet 5.5 inches

Draft Marks

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For example, the density of fresh water is 1.000. Thismeans that one cubic metre of fresh water weighs onemetric tonne. The density of salt water is 1.025, so onecubic metre of salt water will weigh 1.025 metric tonnes.

Three other terms that you need to know are: lightshipweight, deadweight, and load displacement.

The term gross ton is a measurement of space notweight. One gross ton is equal to 100 cubic feet.Spaces that cannot carry cargo (for example crew accommodation space) may be “deducted” from thegross tonnage to get what is called net tonnage. A vessel’s net tonnage is generally considered to be thespace that can carry cargo and thus is revenue producing.

Lightship Weight:actual weight of avessel when empty.

Load Displacement:lightship + deadweight =load displacement

Deadweight: actualamount of weight that avessel can carry whenloaded to the maximumpermissible draft.

Why is a Gross Ton 100 Cubic Feet?Originally wine was carried in vats or casks that werecalled “tuns”. One tun of wine occupied approximately100 cubic feet. Taxes were levied on wine carrying shipswith the amount being based on the number of tuns ofwine the ship could carry.

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In your own words describe Archimedes’ Principle.

Define light displacement, deadweight, and load dis-placement. If a boat has a light displacement of 80tonnes and a loaded displacement of 100 tonnes, howmuch deadweight is on board?

If a fishing vessel’s light displacement is 50 tonnes and 5tonnes of fuel is taken on, and 10 tonnes of fish areloaded, what is the load displacement?

What is freeboard and why is it important?

If a vessel has a draft forward of 4 feet, and a draft aft of6 feet, what is the mean draft?

What is the density of salt water? Explain your answer.

What is gross tonnage?

How do you read the draft of a vessel from the draftmarks? Sketch your answer.

A vessel has a draft forward of 5 feet and a draft aft of 3feet. What is the trim, and is the vessel trimmed by thehead or by the stern?

Do you think the ark could have held all the animals andstill have had sufficient reserve buoyancy?

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Questions for discussion

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Fishing Vessel Stability... talking the talk

As a fisherman you already understand many of theterms and definitions in this chapter. “Talking the talk”is about putting proper names to what you may alreadyknow intuitively from experience, and explaining how allthe terms and definitions work together to describesome principles of fishing vessel stability.

A stability “vocabulary” will enable you to discuss stabil-ity with a naval architect and other fishermen, and makesound operating decisions in your fishing operations.

Transverse StabilityStability is defined as a vessel’s ability to return to theupright when heeled by an external force. The terms,definitions and principles in this chapter come under thegeneral heading of transverse stability. There are otherconsiderations that relate to longitudinal stability.

Centre of GravityThe centre of gravity (G) is the point at which the weightof the vessel and everything on board can be said to actvertically downwards through. The centre of gravity willmove towards weight added, and away from weightdischarged.

The force of gravity isequal to the displace-ment weight of the vessel in any particularcondition of load.

Centre of BuoyancyThe centre of buoyancy (B) is at the geometric centreof the underwater portion of the vessel. Because theshape of the hull is known, a naval architect cancalculate where thecentre of buoyancy is indifferent conditions ofload and degrees ofheel. The force of buoy-ancy acts upward and isequal to the displace-ment weight of thevessel in a particularcondition of load.

KK

G

K

B

K

K

K

HeelThe term heel refers tothe number of degrees avessel is inclined fromthe upright by an externalforce such as wind orwaves.

Talk the Talk Centre of gravityCentre of buoyancyHeelListMetacentreGMGZ righting leverMoment of statical stabilityStiffTenderMoment

ListA vessel has a list wheninclined by the off centerloading of weights. Avessel with no list is saidto be “on an even keel.”

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Vessel in the Upright ConditionWhen a vessel is floatingupright in still water the centreof buoyancy (B) and the centreof gravity (G) will be verticallyin line over the keel (K).

K

B

G

K

B

G

B1

K

B

G

B1

M

MetacentreVertical lines drawn from thecentre of buoyancy (B1) atconsecutive small angles ofheel up to about 15°, willintersect the vessel’s centre-line at a point called themetacentre (M). Think of themetacentre as being a pivotpoint that the vessel inclinesaround at small angles ofheel.

The Shift of B to B1

When a vessel is heeled by anexternal force, a wedge ofbuoyancy is brought out of thewater on one side, and a simi-lar wedge of buoyancy isimmersed on the other side.The centre of buoyancy, whichis always at the geometricalcentre of the underwater por-tion, will move to B1.

Stable EquilibriumA vessel is stable if it tendsto return to the verticalupright position whenheeled. For a vessel to bestable, M must be above G,and the vessel is said tohave positive GM.

K

B

GM

K

B

G

B1

M

K

B

MG

Metacentric HeightThe metacentric height (GM) isthe distance between the centreof gravity and the metacentre.If G is low in the vessel the GMwill be greater than if G is higher in the vessel.

Unstable EquilibriumIf G is above M the vessel issaid to be unstable and hasa have negative GM. Whena vessel with negative GM isheeled, it will tend to heelfurther over and could be indanger of capsizing.

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Tender VesselsVessels are sometimes described as being tender orstiff. If fish or other weights are added on deck orhigher in the vessel, the centre of gravity (G) willmove towards the weight added and decrease themetacentric height (GM). A tender fishing vessel hasa small GM, will be easily heeled, and return slowlyto the upright. If the vessel “hangs” at the end ofeach roll before returningto the upright, weightshould be lowered inthe vessel to increasethe GM.

Stiff VesselsWeight added low in the vessel will cause (G) tomove down towards theweight added, thusincreasing GM. A stiffvessel has a large GM,is comparatively difficultto heel, and will return tothe upright quickly.A very stiff vessel can bequite uncomfortable.

Righting LeverWhen a vessel is heeled byan external force, the centreof gravity (G) remains in thesame place if all weights onboard are secure and donot shift. The centre ofbuoyancy (B) will move tothe geometrical centre ofthe underwater volume toB1. Now the force of gravitywill act vertically downwards, and the force of buoyancywill act vertically upwards.

The horizontal distance from the centre of gravity (G) tothe vertical line from B1 is called the righting lever. Thelength of the righting lever can be measured, and is oftencalled GZ, or the GZ righting lever.

K

B

MG

K

B1

G

M

Z

B

K

B

GM

K

G

M

B

Tender

Stiff“At the time of departure, the vessel was heavily ladenwith traps and gear on deck which raised the vessel’s centreof gravity.” (TC Report No. 495)

Neutral EquilibriumWhen a vessel’s centre of gravity (G)and the metacentre (M) coincide, the vessel is in neutral equilibrium meaning there is no GM. If thevessel is inclined to a small angle it will tend to remain at that angle of heel.

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Describe what has happened inthe illustration below.

K

G

M

Z1

Z2

B1

G2

G1Z

K

B

G

B1

M

Z

Activity Sheet... a picture is worth a thousand words

A QuestionLook carefully at the picture below. GZ is the initial right-ing lever. If weight is added low in the vessel a newlonger righting lever G1Z1 occurs. And if weight is addedhigh in the vessel the righting lever is shorter, shown asG2Z2.

What general conclusions can you make about the rela-tionship between metacentric height (GM) and the lengthof the GZ righting lever?

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What is a MomentA moment is the combination of a distance and a force.A simple concept of moments can be shown with apicture of a seesaw.

The fish on the seesaw do not have the same forcebecause they do not weigh the same amount. Why is theseesaw balanced? Because the big fish is two metresfrom the fulcrum point and the little fish three metresfrom the fulcrum point - which means their weight x thedistance they are positioned from the fulcrum point havecreated the same moment.

big fish: 1 metre x 60 Kgs = 60 Kg/metreslittle fish: 3 metres x 20 Kgs = 60 Kg/metres

We can also get the seasaw to balance if we load twoweights at certain distances so that the total momentsequal the total moment on the other end of the seasaw.

Another example of a moment is when a person jacks upa car to change a flat tire. The weight of the person actingon one end of the jack (which has a certain length) iscreating a moment of force. A very small person mighthave difficulty jacking up a car. The solution would be toget a longer jack (or gain a lot of weight and come backlater to fix the tire).

Moment of Statical StabilityVessels return to the upright because the force of gravityacts downwards through (G), at the end of a distancewhich is the length of the GZ righting lever. Rememberthat the force of gravity actingdownwards is equal to thedisplacement weight of thevessel. The length of the GZrighting lever depends onwhere the centre of gravity is,which depends on how thevessel has been loaded.

displacement = 60 tonnesGZ = 1.2 metres60 tonnes x 1.2 metres = 72 tonne/metresmoment of statical stability = 72 tonne/metres

K

B1

G

M

Z

B

1 Metre3 Metres

60 Kg 20 Kg

1 Metre

2 Metres

60 Kg 10 Kg

5 Metres

8 Kg

“The centre of gravity was raised because the load wasstacked and secured on deck.” (TSB Report No. M96L0037)

“A larger seine net was being used (which was found toweigh 7.4 tonnes). This weight was heavier than the seinenet usually carried, which weighed approximately4.5 tonnes. The nets were routinely stowed on the powerdrum located 1.75 metres above the main deck, wheretheir weight effectively raised the vessel’s centre of gravity.”(Reflexions Issue 21, March 2004, p. 3)

moment = 10 Kg x 2 = 20 tonne/metresmoment = 8 Kg x 5 = 40 tonne/metres

total moment = 60 Kg/metres

...

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Sketch a vessel with positive stability showing the relativepositions of the centre of gravity, centre of buoyancy, keeland metacentre.

What is the difference between a list and a heel?

What happens to a vessel’s centre of gravity if weight isadded high up? What then also happens to GM?

Sketch a stable vessel heeled showing the GZ righting lever,metacentre, centre of gravity, centre of buoyancy and B1.

Why is the position of the centre of gravity so important tovessel stability? How can a skipper control the height of thecentre of gravity?

What does the roll period of a vessel indicate to a skipper ifit is very slow? If the roll period is very quick?

What can make a fishing vessel unstable? Sketch youranswer.

Describe events that might occur during a fishing trip thatcould cause a vessel to become unstable.

What is the moment of statical stability, and what determines the force of that moment?

A vessel has a KG of 7.4 feet and GM of 1.0 feet.What is the KM?

A vessel’s KG is 6.9 feet and KM is 7.2 feet. What is the GM?

A vessel’s KM is 8.1 feet and GM is 1.4 feet. What is the KG?

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Questions for discussion

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Inclining Experiment and Stability Book

In the previous section you worked with hypotheticalvalues for KM, GM, and KG and it was shown that if youknow any two of these values, the third can be calculat-ed. This section will explain how the real value for GM isdetermined by an inclining experiment and then how theactual centre of gravity of the vessel can be establishedin lightship condition. This section will also explain howa stability book is developed, and the information it con-tains, including notices to skippers about the stability oftheir vessel. Finally the roll period test will be explained,including its limitations.

The Inclining ExperimentAn inclining experiment consists of shifting knownweights transversely across the deck of a vessel througha known distance. The vessel must be free to heel whenthe weights are shifted. A measured plumb bob line issuspended amidships from a cross beam in a hatch. Agraduated ruler is placed below the plumb bob with zerounder the bob so that when the vessel is heeled, thedeflection distance of the plumb bob can be read off theruler.

For optimum accuracy, a minimum of eight weight shifts ismade and deflections noted and tabulated:

Shift Weights Direction Deflection1 1,000 lbs. P to S 2 5/16”2 1,000 P to S 2 1/4”3 1,000 S to P 2 5/16”4 1,000 S to P 2 1/4”5 1,000 S to P 2 1/4”6 1,000 S to P 2 1/4”7 1,000 P to S 2 5/16”8 1,000 P to S 2 1/4”

total deflection 18.1875”8

mean deflection 2.27”

In the following formula:w = the weight movedd = the distance through which the weight is moved

W = the displacement of the vessel at the drafts as inclined

w x d x length of pendulum W x deflection of pendulum

1000 x 19.83’ x 108.375”(2240 x 155.22) x 2.27”

GM = 2.72’ (Regulation requires that initial GM should not be less than 1.15’)

Vertical Upright

Leng

th o

f plu

mb

bob

Vessel Heeled by Shifted Weight

Leng

th o

f plu

mb

bob

deflection

The naval architect conducting the inclining experimentmust have a set of lines plans for the vessel. Theseplans show the actual shape of the vessel hull.

Talk the Talk Inclining experimentLines plansNaval architectStability bookSTAB 4Stability curvesArea under curveTank soundingsLimiting KGVCGNotice to SkipperRoll period testLimitations to roll

period testHydrostatic curvesTonnes per CM

immersion (TPC)

...

GM =

GM =

(The vessel in this example has a displacement of 155.22 tons)2240 x 155.22 tons = 347692.8 lbs.

K

M

G

B

The Stability BookOnce the lightship displacement and KG have beendetermined, the vessel’s stability characteristics in otherconditions of load can be calculated. Remember fromthe last section that the centre of gravity moves towardsweight added, and away from weight discharged. Thenaval architect has drawings that show how high abovethe keel in the vessel different weights are located, suchas a drum on deck. There are also tank capacity tablesthat show the weight of fuel oil or fresh water at differentlevels. Today, stability calculations for different loadconditions are for the most part done by computer andmade available to the owner and skipper in the form ofa stability book.

Transport Canada requires in addition to lightshipcondition, that certain other conditions of load, as notedin bold, have stability information calculated.

Departure – 100% Fuel Oil, Fresh Water, and StoresArrival grounds – 75% Fuel Oil, Fresh Water, and StoresHalf load – 55% Fuel Oil, Fresh Water, Stores, 50% FishFull load – 35% Fuel Oil, Fresh Water, Stores, 100% Fish (*) Arrival port – 10% Fuel Oil, Fresh Water, After discharge – 10% Fuel Oil, Fresh Water, Stores

For the vessel above, conditions 5 and 6 have additionallybeen calculated. The “worst operating” condition mustalso be identified, which is the vessel in the above condition 4(*). This means that in condition 4 the vesselhas the least amount of righting energy, although it stillmeets or exceeds minimum righting energy requirements,called Stability Standards for Fishing Vessels andreferred to as Stab 4.

1.2.

3.

4.

5.6.

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KM determined by naval architect: 13.19 feetGM determined from inclining experiment: 2.72 feet

KG = KM – GMKG = 13.19 feet – 2.72 feet

KG = 10.47 feet (the centre of gravity as inclinedis 10.47 feet above the keel)

...

In practice when an inclining experiment is conducted,the vessel may not actually be in lightship condition. To get the actual lightship displacement and lightshipKG, the naval architect will subtract weights not part oflightship, and make a correction to the as inclined KG toget lightship KG.

Before doing the test, the drafts f orward and aft aretaken, and with this information and the lines plans, theunderwater volume can be determined and hence thedisplacement weight of the vessel as inclined. If you do not have lines plans for your vessel, a navalarchitect can create them by taking certain very precisemeasurements of your vessel when it is out of the waterand then entering that information into a computer thatwill generate lines plans information.

With the lines plans a naval architect can also determinewhere M is for the specific vessel being inclined.

15°Angles In Degrees

GZ

In M

etre

s

30° 45° 60° 75° 90°0

1

15° 30° 45° 60° 75° 90°0

1

Angles Of Heel

GZ

In M

etre

s

Ran

ge

Max

imu

mSt

abil

ity

Leve

r

G

B

M

Z G

B

M

Z G

B

M

Z G

B

M

Z

You can request that stability information be calculatedfor specific conditions of load that you know you operatein, but that are not required.

For each condition of load, stability information is calculatedand presented as tables, graphs and stability curves.

Stability Curves Stability curves are drawn that show the righting leversdeveloped in different conditions of load and angles ofheel. In the example below the GZ righting lever at 10˚ ofheel is about .25 of a metre. At just over 25˚ of heel, therighting lever is about .75 of a metre. The maximumrighting lever occurs at just over 45˚ angle of heel, andis slightly over 1 metre. In a different condition of loadthe stability curve will look slightly different, but will stillmeet stability requirements.

STAB 4 requires that the righting lever GZ be at least0.656 feet (0.2 metres) at an angle of heel equal to orgreater than 30˚ angle of heel. Also, the maximumrighting lever should occur at an angle of heel preferablyexceeding 30˚ but not less than 25˚.

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Different structural features will result in different stabili-ty characteristics such as the beam to draft ratio and theamount of freeboard. An increase in beam will result inan increase in the GZ righting lever at all angles of heelas shown below in comparison to the vessel in the previ-ous illustration.

The area under the curve can be calculated and indicatesthe amount of righting energy a vessel has in thatparticular load condition.

Limiting KGAnother way of presenting stability information is theconcept of limiting KG which is a measure of the mini-mum stability required to ensure that a fishing vessel isstable throughout a voyage in different conditions ofload. Remember that KG identifies how far above thekeel the vessel’s centre of gravity is located.

If the concept of limiting KG is used, the stability bookwill contain reference tables indicating changed valuesfor weights in the various conditions of load. From thesetables the vessel’s KG can be calculated and compared toa predetermined curve of maximum acceptable limits toascertain whether the vessel meets minimum stabilityrequirements based on KG.

Do the vessels inthese illustrationsmeet the require-ments of Stab 4 ?

Keel

1.15 m

1.4 m

Base Line

FSM 0.65 TmFore Deck

29 30

In this example Condition No.5 is for 100% Fish and 20%Fuel and Water. The sounding is greater than 20% capacity,and the prudent skipper wants to know if this extra waterwill adversely effect the vessel’s stability.

The Displacement Table lists items on board. Each itemlisted in column 2 is located a certain distance from thekeel and has its own vertical centre of gravity (VCG).Column 3 gives the vertical moment in tonne/metres ofeach item. Remember from the last section that amoment is a weight times a distance. In this case theVCG of each item is the distance.

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0.20.40.60.81.01.21.41.61.82.0

Soundings(m)

Capacity(Tonnes)

VCG(m)

LCG(m)

0.10.20.40.650.951.301.702.12.452.85

0.650.750.850.951.151.251.351.451.551.65

4.74.724.744.774.84.824.854.884.914.94

The sounding information can then be entered into the following Displacement Table.

Fresh WaterE. R. Wings FOLub, OilCrew & effectsStoresProvisionsCatch

B Deadweight

C Lightship

D Displacement

WeightTonnes

(1)

VCGm(2)

LCGford/aft

amidshipm(4)

VerticalMoment

Tm(3)

FreeSurfaceMoment

(6)

Long-A1MomentItem

1.709.500.101.002.000.40

24.00

38.70

148.46

187.16

1.352.252.594.003.002.002.60

3.48

3.28

2.2921.37

0.254.006.000.80

62.40

97.11

516.61

613.72

+ 4.85- 4.77- 7.90+ 6.00

—+ 7.00+ 0.50

--

- 0.60

+ 8.24- 45.32- 0.79+ 6.00

—+ 2.80+ 12.00

- 17.07

- 96.00

-113.07

0.650.880.18

—

—

1.71

Displacement TableCondition No. 5 Fishing 100% Catch 20% Fuel and Water

weight x distance

total momentstotal weight

613.72 tonne/metres 187.16 tonnes

3.279 or 3.28 metres

moment =

distance =

KG=

KG=

remember the formula

rearrange the formula

distance is the vessel’s KG

the tonnes cancel and

Below is an example of a fresh water tank capacity table.It is entered with the sounding obtained, which in thiscase is 1.4 metres. A sounding of 1.4 metres, from thetable, means that the capacity at that sounding equals1.70 tonnes. Also at that sounding, the VCG (vertical centreof gravity) of the 1.70 tonnes is 1.35 metres above the keel.

Fresh Water Tanks, Port and Starboard

21

Activity Sheet... you do the math

160 170 180 190 200 210 220 230 240 2503.0

3.1

3.2

3.3

3.4

3.5

3.6

3.7

Displacement Tonnes

KG

Met

res

Curve Of Limiting KG

4.03.483.02.602.592.252.01.35

?

Item VCGMetres

WeightTonnes

1.0148.47 2.0 24.0

.109.50

.401.70

xxxxxxxx

Vertical MomentTonne/Metres

516.61Crew & Effects

LightshipStores

Catch FishLube, Oil

E/R Fuel/OilProvisions

Fresh Water

Vessel KG

Total Weight

Total VerticalMoments

In any condition of loading the KG from line D of theDisplacement Table or as you just calculated, must liewithin the area under the curve.

In Condition No. 5, with the actual amount of fresh wateron board, the vessel’s KG is 3.28 metres. Is this KG toohigh for adequate stability? Now consult the Curve ofLimiting KG Table shown to the left. This curve tells usthat in any condition of load the KG of the vessel must bebelow the curve indicated. Now enter the curve with thedisplacement of the vessel (187.16 tonnes) along the bot-tom, and the KG (3.28 metres) on the vertical. The blackdot representing these two values is indeed below thecurve of limiting KG and the vessel has adequate stability.

We want to know where the vessel’s KG is given allthe weights, each with their own vertical centre ofgravity, including lightship displacement weight andthe lightship KG.

Step 1: multiply the VCG and the weight to get vertical moment

Step 2: total the weights

Step 3: total the vertical moments

total momentstotal weight

KG = _____________

Did you get the same answer as on the previous page?

KG =

500 550400 450 600

35 40 45

Dra

ft in

Met

res

Displacement in Metric Tonnes

Hydrostatic Curves

M CT 1cm(Tonnes -Metres)

TPC

12

11

5

10

6

9

7

3

4

8

metres aft metres fwd5 5

Tonnes Displacement

Lon

gitu

din

alCen

treo

fB

uo

yancy

Lon

gitu

din

alCen

treo

fFlo

tation

Ton

nes

Per

CMIm

mer

sio

nM

om

ent

toCh

ange

Trim

OneCM

20000 25000 30000 35000 40000 45000 50000 5500015000

22

Hydrostatic InformationA stability book will also provide what is called hydrostaticinformation that is governed by the overall dimensionsand underwater shape of the vessel. It may be presentedin a table format, or more often as hydrostatic curves.

If the displacement of a vessel is required for a meandraft of 5 metres, locate the draft on the left hand verticalscale. Then draw a horizontal line through the draft tocut the Tonnes Displacement curve. Draw a perpendicu-lar up to the horizontal scale at the top and read thedisplacement. In this example 22,000 metric tonnes.

The Tonnes per CM Immersion (TPC) curve tells you at acertain draft how many tonnes of deadweight added willincrease the draft by 1 cm. Again, at a mean draft of 5metres, move horizontally across to the TPC curve anddrop a perpendicular to the TPC scale along the bottom.In this example it will take 38 tonnes to increase thedraft of the vessel by 1 cm.

Hydrostatic curves are fundamentally the same in howthey are used to obtain information that is relevant tothe stability of a vessel. It is standard practice to assumethe vessel is upright on an even keep, and floating is seawater with a density of 1.025.

Stability and Hydrostatic Curves

Notice to SkipperA stability book, sometimes called a “trim and stabilitybook”, generally will have a section called Notice toSkipper. Here are examples of what you might expect tofind in the notice.

The seagoing condition of operation set out in this book indicatethat the vessel meets or exceeds the minimum stability require-ments of Transport Canada for fishing vessels of this size.However, compliance with these minimum requirements doesnot ensure immunity against capsizing or foundering or absolvethe skipper from his responsibilities with regard to prudenceand good seamanship.A high centre of gravity is detrimental to safe vessel operationand in heavy weather every effort must be made to reduce topweight such as lowering boom and stowing net in the hold.Slack tanks should be kept to a minimum and bilges pumpedout.During the general operations of the vessel, weight additionsmust be kept to a minimum and any added weights should beplaced as low in the vessel as possible. Care should be takenwhen stowing gear or fish to ensure that the vessel is notoperated outside the conditions shown in this book.Use of oil, fuel and water, and filling of fishholds should besuch as to ensure the minimum trim in any condition.Trim can be controlled by transferring F/W from one F/W tankto the other, either forward or aft whichever is required tominimize trim.Before sailing care should be taken to ensure that the net andskiff are properly stowed and lashed down and that all man-holes and hatches on the open deck have been securelybattened down and that storm shutters have been fitted on thefoc’sle hull side windows.

Note: The stability conditions in this book have beenprepared based on the following:

There are 4.491 tonnes of permanent lead ballast at the for-ward end of the engine room.A wet weight of seine net of 5.45 tonnes and skiff at 1.80tonnes.

The net is on the drum in all working conditions.The forepeak tank should be kept full at all times unlessrequired for an emergency.The full upright fee surface of two of the four fishhold tankshas been taken into consideration. To reduce the free surfaceeffect it is recommended that the holds be filled to the hatchcoamings whenever possible and that the two diagonal tanksbe filled as quickly as possible. In filling the fishhold only twoholds are to be filled at a time and the order of filling should befirst one set of diagonal holds and the opposite two diagonalholds.All openings in the superstructure are to be fitted with weather-tight closing appliances. The first superstructure openings thatare not fitted with weathertight closing appliances are theengine room vents.In all conditions, and based on (6) above, the angle ofdownflooding is in excess of 40°.When the boom exceeds 10° port or starboard of the vesselcentreline, the stability of the vessel should be considered.

Vessels operating in trap fisheries could be expected tohave a notice related to the number of traps and howthey are placed on the vessel. Also, some vessels mayhave fuel oil transfer or ballasting sequences specified.

If your vessel has a stability book written for one fisheryand you have modified the vessel for a different fishery,the conditions given in the stability book are no longerapplicable, and a naval architect should be consulted.Keep in mind that operating outside of the parametersstated in the stability book, for example removing ballastthat was part of the original calculations could in somecircumstances have legal consequences if you areinvolved in an incident. It would be prudent to checkyour insurance policy to see if there is a clause thataddresses vessel modifications other than as designed.

1.

2.

3.

4.

5.

6.

1.

2.

3.4.

5.

6.

7.

8.

23

The Roll Period TestIt is possible to estimate a vessel’s GM (metacentricheight) by means of a roll period test. This has somevalue because GM is one measure of a vessel’s stability.However, a roll period test is not a substitute for aninclining experiment, and the GM from a roll period testcannot be used to determine KG or to generate informa-tion about different conditions of load.

The roll period of a vessel depends on the beam of thevessel and height of the centre of gravity (KG). You can’tdo much about the beam, but you can endeavour tokeep the centre of gravity low in the vessel by how youload it.

You can conduct a roll period test yourself. Select a calmday, secure all weights on board, and be sure there areno slack tanks. Loosen the mooring lines and set thevessel rolling by pulling on a masthead line from thewharf, or by getting several people to move athwartshipsin unison, or by having people forcibly generate freerolling of the vessel by pushing one side of the vesseldown and then releasing it.

Use a stopwatch and time each complete roll period,which is from a start position full over to one side, overto the other side and then back to the start position.Repeat the procedure several times until the timedresults are coming out consistently.

The formula for calculating GM is:

For example, the GM for a vessel with a beam of 5 metres, a rollperiod of 5 seconds, using .6 as the f coefficient would look like this:

24

K

G

B

M

K

G

B

M

K

G

B

M

To use this formula requires an f coefficient or factor.The f value may be anywhere from .6 to .8 depending onthe design of your vessel. You might want to consult anaval architect as to what value they suggest you usebased on your vessel. The beam is measured in metresand the roll period measured in seconds. What you usefor the f coefficient will make a difference in the calculatedGM. This is another limitation of the roll period test asan accurate indicator of stability.

Nonetheless a roll period test is a way you can monitoryour vessel’s GM. If at the beginning of each season youconduct a roll period test each time in a similar conditionof load, and notice that the GM value is getting smaller,you might want to talk with a naval architect.

If you have a full inclining experiment done on yourvessel, ask that a roll period test also be conducted.That way you have a roll period GM to compare rollperiod test results done the following year.

GM = f x beam 2

roll period( (

GM = .6 x 5 2

5 sec.

GM = .6 x 5

5 sec.

GM = 3

5 = .6

GM = .6 x .6 = .36 metre

( (

Start Time Stop Time

Conditions Necessary for the Inclining Experiment:

25

What it All Adds Up ToThis section has presented a lot of information that includednumbers and math calculations. You are not expected tobe a naval architect and a whiz with the numbers. You area fisherman and your job is to catch fish and make a living– safely. It is important though that you appreciate thatthe calculations and stability data that a naval architectpresents in a stability book are not as obscure as theymight look when you first open a stability book and try tomake the information useful. Understanding a stabilitybook begins with knowing the terms used and understand-ing what they mean. If this section has been confusing,talk with a friend and work through it again together.

You can’t do much about the hull form of your vessel, butyou are very much in control over the centre of gravity ofyour vessel by how you load it. In general terms the lowerthe centre of gravity the more stable your vessel will be.If you have a stability book, be sure you are familiar withthe Notice to Skippers and operate accordingly. If youmodify your vessel for a different fishery from what it wasdesigned for, you should consult with a naval architectabout how the modifications may affect your vessel’sstability.

Mooring lines must be slack and the vessel clear of thedock so that it heels freely.The water must be smooth and there should be littleor no wind.There should be no free surface water in the vessel, the bilgesshould be dry and tanks dry or pressed up fully.All moveable weights must be properly secured.All persons should be ashore except those actually engagedin the experiment.The vessel must be upright at the beginning of theinclining experiment.

.

.

.

..

.

What information does an inclining experiment provide?

Why are lines plans necessary to conduct an incliningexperiment?

What is meant by “worst operating condition” as indicatedin a stability book?

In general terms what is meant by a stability curve?

What are some structural features that will affect a stability curve?

What is meant by a curve of limiting KG?

What information can be determined from a tank capacitytable?

What information does a displacement table provide?

What kind of information is found in the Notice to Skipperincluded in a stability book?

What information does a roll period test provide, and whatare the limitations of a roll period test?

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Questions for discussion

26

27

The operation of a fishing vessel is considerably differentfrom that of other commercial vessels who load in portand close the hatches until they are alongside to dischargecargo at their destination port. Catch and loadingoperations while at sea are a routine occurrence forcommercial fishermen, often in less than ideal weatherconditions.

Because loading for the most part is done at sea, it maybe difficult to immediately observe the effect of the oper-ation. You want to have a practical working knowledgeof vessel stability, and know how to avoid operations orload conditions that sometimes, with no warning, cancompromise a vessel’s stability to the point of capsize.

In the last section we looked at how a naval architectdetermines a stability profile based on a vessel’s KG indifferent conditions of load. The information is presentedas tabulated data and with a righting curve that graphicallyshows the GZ righting lever at different angles of heel.The area under the curve represents the amount of righting energy a vessel has in different conditions ofload and at different angles of heel.

15° 30° 45° 60° 75° 90°0

1

Angles Of Heel

GZ

In M

etre

s

Ran

ge

Max

imu

mSt

abil

ity

Leve

r

G

B

M

Z G

B

M

Z G

B

M

Z G

B

M

Z

When a fishing vessel capsizes it is generally notbecause of any one factor that has reduced the rightingenergy. It is the cumulative effect of multiple factors thathave compromised a vessel’s ability to return to theupright. This section identifies operating factors that, ifcombined, can lead to a fishing vessel capsize.

This section also talks about the factors that can com-promise a fishing vessel’s righting energy. The graphicpresentations are not vessel specific, and only representgeneral principles about the loss of righting energy whenfactors that compromise vessel stability are present.

To help organize this information, factors that compromisestability have been grouped under four general headings:• Freeboard is Your Friend• Free Surface• Fishing Operations• Stability and Weather

How Fishing Vessel Stability is Compromised … the good, the bad and the ugly

Talk the Talk Deck edge immersionVirtual rise of GDownfloodingAngle of lollEffect of suspended

weightCumulativeCompromised stabilityEffect of following seasEffect of free surfaceTowingShifting weightsVessel modificationsLoad height

Note: The examples on the following pages are pictorialrepresentations of different factors that can compromisevessel stability. They are not intended to be an exact representation of how these factors effect any specific fishing vessel.

28

k

m

b1b 0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energyg z

k

m

b1b0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)Righting Energy

g z

Freeboard is Your Friend... why?You cannot change the hull form of your vessel, which atdifferent drafts determines the distance B will move to B1when the vessel is heeled, and thus the amount of rightingenergy available. However, as skipper and crew you areresponsible for managing weight taken on board andhow it is loaded.

How you manage weights on board determines the centreof gravity of your vessel and the vessel’s righting energy.The center of gravity constantly changes because of howyou load the vessel, the amount of consumables on board,fuel transfer and ballast sequencing, tanking down,fishing operations using the boom, towing a skiff, towing a trawl, or carrying trapsfor prawn, crab or black cod.

Deck Edge ImemersionTransportation Safety Board investigations report thatthe lack of freeboard is consistently a major contributingfactor in fishing vessel capsize. The reason is becausedeck edge immersion will happen sooner when there isreduced freeboard. When deck edge immersion occurs,the shape of the underwater portion of the hull changes,and dramatically reduces how far out to the low side Bwill move to B1. This reduces the length of theGZ righting lever and the righting or energy availableto return the vessel to the upright.

Condition 1: adequate freeboard

Condition 2: deck edgeimmersion

Always maintainadequate freeboard.

29

K

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

12.0 Righting Energy

K

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

9.0Righting Energy

OverloadingOverloading has been identified as another commoncause of fishing vessel capsizings. If weight is on deck,the centre of gravity is higher. Added weight means thefreeboard has been reduced and deck edge immersionwill occur at smaller angles of heel.

Vessels also get heavier as they get older. This can bedue to accumulated equipment on board, and itemsstowed in the crew quarters, engine room, lazarette andon top of the wheelhouse.

Condition 1: 9.0 foot draft

Condition 2: 12.0 foot draft

“The cumulative weight of trawl fishing equipment andthe additional gear stowed in the lazaret, on the wheelhouse top and lashed to the forecastle deck side railings,raised the vessel's’centre of gravity and detrimentally affectedthe vessel's stability characteristics.”

(TSB Marine Occurrence Report No. M97W0236)

Overloadingreduces freeboard.

30

K

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— DegreesG

Z R

igh

tin

g Le

ver

(ft)

Righting Energy

K

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energy

Condition 2: after modifications

Vessel ModificationsWhen a vessel built for one fishery is modified to participatein a different fishery, the centre of gravity as designed isoften raised due to adding additional gear. If the newfishery requires greater traveling distances, 45 gallondrums of fuel have on occasion been carried on deck.Carrying additional traps other than the number allowedby original design can also seriously compromise a vessel’sstability and righting energy. This is because the extaweight increases the draft and decreases the freeboard.

Condition 1: before modifications

Get professional advicebefore making any majormodifications to your vessel.

31

K

G

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energy

K

G

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energy

Load HeightStowing the catch down below increases the vessel’sstability, as opposed to carrying catch on deck whichraises the centre of gravity. It is not just the height of theload carried, but fuel consumed will also increase theheight of the centre of gravity. When traveling, seinenets are commonly stowed on deck or in the hatch tolower the centre of gravity and increase the vessel’srighting energy.

Larger vessels that have ballast tanks may have a Notice toSkippers in the stability book that give the acceptablesequence for fuel consumption, transfer and ballastoperations. The naval architect has designed the vesselso that the instructions maintain optimum stability conditions.

Condition 1: fish in holdhalf full (with centre linebulkhead)

Condition 2: fish on deck

32

Reserve BuoyancyNewer vessels are constructed with lots of reserve buoyancy.Look at your vessel and think about how much reserve buoy-ancy you have when the boat is fully loaded.

Open doors and hatches can allow flooding of compartmentsthat are meant to be watertight and contribute to the vessel’sreserve buoyancy. Watertight doors that are left open maycompromise reserve buoyancy in the event of flooding andthereby compromise the vessel’s stability.

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energy

Condition 1: two level deckhouseand large forward watertightcompartment provides additionalreserve buoyancy

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— DegreesG

Z R

igh

tin

g Le

ver

(ft)

Righting Energy

Condition 2: single level deckhouseand small forward compartment

20 feet x 20 feet 12 x 2 feet = _____ feet

33

Free Surface

Water in the fish holds, a tank half full of water or fuel, ahold partly filled with herring in bulk, water on deck, andflooded bilges are all examples of free surface. A liquidsurface that is free to move raises the vessel’s centre ofgravity and dramatically compromises the vessel’s trans-verse stability.

In fact, the vessel will act as though the weight of theliquid with the free surface is higher in the vessel thanin reality it actually is.

How much higher? Here is the calculation process.

multiply the athwartships width of the free surface(in feet) by itselfdivide by 12divide by the average depth of the liquid (in feet)

Let’s do some calculations. Suppose a tank is twentyfeet wide from port to starboard and has two feet of saltwater in it.

The vessel will act as though the weight of the water is__________ feet higher than it actually is. This reality is calledthe virtual rise of G.

To figure out the weight of water in this example, let us supposethe same tank measures 10 feet fore and aft. The volume of saltwater will be:

10 feet x 20 feet x 2 feet =__________ cubic feet

Salt water weighs 64.2 pounds per cubic foot. What is the weight of the water in the tank?

64.2 pounds x ______ cubic feet = ___________ pounds

If there are 2,240 pounds to one tonne, how many tonnes doesthe water weigh?

2,240 pounds x __________ pounds = ___________ tons

The vessel will act as though ___________ tons has been moved _________ feet higher than where it actually is, signifi-cantly raising the centre of gravity and decreasing the vessel’smetacentric height.

Tanks are generally baffled to prevent the detrimental effect offree surface. However, a flooded lazarette with no centre linedivision will seriously compromise a vessel’s stability and righting energy.

From the calculation you just did, what conclusions can youdraw about the effect of free surface on fishing vessel stability?

“In general, few fishermen fully understand free surfaceeffect and fewer appreciate the substantial loss of transversestability when water, even a few inches is shipped andretained on deck…when the deck edge is submerged, theeffect can be disastrous.”(TC Marine Casualty Investigations, Report No. 495)

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..

Activity Sheet... weighing in

1.

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3.

4.

K

G

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energy

K

G

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— DegreesG

Z R

igh

tin

g Le

ver

(ft)

Righting Energy

34

Effect of Free Surface on DeckWater trapped on deck will seriously threaten a vessel’sstability and dramatically reduce the righting energy. The greater the surface area covered, the greater theeffect. The area covered with water is more significantthan the depth of water.

Remember:The water will cause a rise in the center of gravity(as if the weight was actually higher in the vessel).The water will increase the displacement,increase the draft, and decrease freeboard.The vessel is vulnerable to deck edgeimmersion.

.

.

.

Condition 1: normal load

Condition 2: water on deck

“Free surface is like lots of heavy canon balls rollingaround all over the deck.” (David l. Green PE, Jensen Maritime Consultants)

Freeing ports must belarge enough to shedwater and never beplugged or covered.

35

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energy

K

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energy

K

Free Surface – DownfloodingDownflooding is the entry of water into the hull whichresults in progressive flooding that pumps cannot keepup with. Watertight integrity is necessary to preventdownflooding. Downflooding introduces free surface,which raises the centre of gravity, increases the draft,reduces freeboard, can cause an extreme list and resultin capsize.

In the illustration where the vessel is downflooding,the area of the curve that shows righting energy stops atjust over 40° because beyond that angle thevessel will not be able to recover.

Condition 1: no opendownflooding points

Condition 2:downfloodingthrough open door

“The weathertight doors from the main deck to the accommodation area and the engine room were secured inthe open position, compromising the watertight integrity of the vessel. This allowed shipped seawater to downfloodinto the hull.”

(TSB Marine Occurrence Report. No. M97W0236)

Carry spare pumps incase of downflooding.

K

G

B1

Z

B

K

B1

Z

B

GM

36

K

G

B1

Z

B

A vessel at an angle of loll may easily flop from one sideto the other. An angle of loll requires an extremely highcentre of gravity, initially a negative GM as we saw in thefirst picture. Generally, the only way the centre of gravitymoves that high is because of excessive free surfaceand the virtual rise of G.

Angle of LollWhen a vessel refuses to stay in an upright condition,although there is no off centre loading to cause a list,then it may be at an angle of loll. This means the vessel is unstable when upright, and will loll to one side or the other to gain what little stability is left.

A vessel with an initial negative GM is unstable when inclined to a small angle.

0 10 20 30 40 50 60 70 80 90

0.3

0.1

0

0.2

Heel In Degrees

GZ

In M

etre

s

Angle OfLoll

0.1

0.2

+

-Neg. GM

As the angle of heel increases the centre of buoyancywill move out still further to the low side until B1 isvertically under G. The initial negative GM is gone andthe vessel is at an angle of loll with no GZ righting lever.

If the vessel is heeled beyond the angleof loll, B1 will move out still further tothe low side and there will be aGZ righting lever that will returnthe vessel to the angle of loll.

An angle of loll isextremely dangerous.

K

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energy

G

K

G

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— DegreesG

Z R

igh

tin

g Le

ver

(ft)

Righting Energy

37

Fishing OperationsLoad ShiftWeights not secured canshift when running in weatheror as a result of fishing operations. A load that hasshifted can compromise vessel stability by reducingthe GZ righting lever and theamount of righting energy.Once the weight has shiftedand causes a list, the boat will not return to the uprightuntil the off centreloading is corrected. In heavy seas, a load shift may not be immediately noticed and the reduction in righting energy is a “silent” compromise in stability.

K

GG1

ZZ

Fuel MigrationFuel tanks that have an open cross connection can com-promise vessel stability if left open, particularly if run-ning in beam seas or with a slight list. As fuel migratesto the low side, the list increases and can result in deckedge immersion, accumulated water on deck and freesurface.

Condition 1: tanks pressed upboat returns to upright position

Condition 2: fuel migration boat does not return to upright position

Don’t leave crossconnections betweenfuel tanks open.

K

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— DegreesG

Z R

igh

tin

g Le

ver

(ft)

Righting Energy

G

K

G

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

2.0

Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energy

38

Suspended WeightsLifting weights with the boom is part of many fishingoperations. The weight lifted will act from the top of theboom at the point of suspension. If one tonne on deck islifted with a boom topped at 20 feet, the weight will actas though it was 20 feet above the deck, which will raisethe vessel’s centre of gravity and reduce the righting energy.

Condition 1: weight on deckand on centre line

Condition 2: weight lifted offdeck, but still on centre line

K

G1

G

0 10 20 30 40 50 60 70 80 90

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1.0

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Heel Angle— Degrees

GZ

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Righting Energy

39

Condition 3: weight liftedover the side

Because the load is now off set from the centerline, thecentre of gravity is shifted to the low side as well asbeing raised because the weight acts from the point ofsuspension, ie. from the top of the boom. The list thevessel experiences also means there is a further reductionin righting energy.

40

Towing Fishing GearThere are several combined factors that effect fishingvessel stability when towing gear. The weight of the loadbeing towed will act from the point of suspension. Thefreeboard will be reduced, particularly at the stern. If thesea is on the beam or the quarter, the towing load is vul-nerable to shifting.

Stability will be affected because the centre of gravity israised as the weight of the tow acts from the point ofsuspension.

0 10 20 30 40 50 60 70 80 90

0.5

1.0

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Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)

Righting Energy

K

BG

M

0 10 20 30 40 50 60 70 80 90

0.5

1.0

1.5

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Heel Angle— Degrees

GZ

Rig

hti

ng

Leve

r (f

t)Righting Energy

K

B

GM

Because there is reduced freeboard and perhaps deckedge immersion, there is a reduction in righting energybecause the movement of B to B1 will be less, and the GZrighting lever reduced.

The considerations while towing fishing gear also applyto towing a skiff. And, turning while towing can furthercompromise a fishing vessel’s righting energy.

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0 10 20 30 40 50 60 70 80 90

0.5

1.0

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Heel Angle— Degrees

GZ

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hti

ng

Leve

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t)

Righting Energy

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Heel Angle— Degrees

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Leve

r (f

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Righting Energy

The effect of excessive stern trim may not be as obviousas other factors that compromise vessel stability, but it isone more condition that when other compromising factorsare present, can be significant enough to reduce rightingenergy to the point where a vessel cannot recover.

Excessive TrimA fishing vessel trimmed significantly by the stern willlose righting energy. Although trim is generally dis-cussed in terms of longitudinal stability, it can have aneffect on transverse stability and the amount of rightingenergy available to return the vessel to the upright. Thisis because a vessel with excessive trim has a differentunderwater volume that will change the shift of B to B1,and can reduce the length of the GZ righting lever.

Condition 1: no trim

Condition 2: trimmed 3 feet by the stern

Significant trim canreduce stability.

0 10 20 30 40 50 60 70 80 90

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Righting Energy

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Stability and WeatherA fishing vessel with modestly compromised rightingenergy may be all right in moderate weather conditions,but getting caught out when the weather comes up andseas build can present other considerations.

Following SeasOperating in following seas can reduce the stability of avessel. Running in a following sea where the length ofthe wave is twice that of the vessel, and the vessel’sspeed is the same as the wave speed, can result in thevessel being “perched” on a wave crest.

This means that only a small part of the underwater hullform is available to develop righting energy. When“perched” on a wave, amidship freeboard is decreased,bow and stern buoyancy are reduced, and the ruddermay not be effective because it is partially out of thewater. In confused seas it may be difficult to determineyour vessel’s relationship to the seas you are running in.

0 10 20 30 40 50 60 70 80 90

0.5

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Heel Angle— DegreesG

Z R

igh

tin

g Le

ver

(ft)

Righting Energy

Condition 1: no waves

Condition 2: perchedon a wave

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Righting Energy

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In heavy weather with a following sea, a vessel can alsoride in the trough of the following sea, which will changerighting energy because the underwater hull volumeavailable to produce righting energy is less. In thetrough, the amidship buoyancy and the stern freeboardcan be significantly reduced.

Condition 3: boat in a troughwith loss of buoyancy

K

G

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Righting Energy

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Effect of IcingIce accumulation on the superstructure and rigging of afishing vessel is a very real threat to stability. Ice accre-tion can be from water droplets on the superstructurecaused by spray from the vessel working in a seaway.Intensive ice formation occurs when the wind and seasare ahead. If the wind and sea spray are on a vessel’sbeam or quarter, then ice will collect to windward andcause the vessel to list. The weight of the accumulatedice can raise the vessel’s centre of gravity very quickly,and if running into a sea can also result in a trim by thehead. A raised centre of gravity and excessive trim bothreduce the stability of a vessel and can seriously impair righting energy.

K

0 10 20 30 40 50 60 70 80 90

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Heel Angle— Degrees

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Righting Energy

G

Condition 2: 20 tons ice 4 inches thick

Condition 1: no iceon vessel

Deck EdgeImmersion -

Downflooding Occurs

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Heel Angle— Degrees

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Loss Of Righting Energy Free Surface On Deck

Loss Of Righting Energy- Minimal Freeboard

Loss Of Righting Energy- Raised Centre Of Gravity

Initial Righting Energy

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Comromised Stability… a cumulative process

Findings

At the time of departure, the vessel was heavily laden with trapsand gear on deck which raised the vessel’s centre of gravity;The total deadweight was increased and the freeboard and transverse stability reduced when the forward fish holds werepumped full of sea water;The reduced freeboard allowed water to be shipped on deck atrelatively small angles of heel;The free surface effect and weight of water shipped and retainedon deck severely reduced the vessel’s transverse stability, andThe reduced transverse stability retarded the vessel’s rate of recovery from an initially moderate roll to port allowing time fordownflooding to commence and continue until the reserve stability was overcome and the vessel heavily listed over and capsized. (TC Investigation Report No. 495)

•

•

•

•

•

It would appear that the following factors contributed to the lossof transverse stability leading to the vessel’s capsize:

46

What does the cumulative effect of threats to fishing vessel stability mean to you?

Why is freeboard your friend?

Explain deck edge immersion and why it is such a threatto a vessel’s transverse stability.

Discuss what is meant by vessel modifications. Whatexamples are you familiar with?

How much of a change to a sister ship hull design do youthink constitutes a vessel modification that could be athreat to stability?

What is meant by fuel consumption, transfer, and ballastoperations, and why do you think it is it important to followinstructions given in a fishing vessel’s stability book?

What does the term virtual rise of G mean?

Many stability books have “Subject to the Angle ofDownflooding Being in Excess of 40 Degrees” stamped on the cover. What does this mean?

When lifting weights with the boom over the side, discusswhat happens to the vessel’s centre of gravity.

Describe the ways that weather can affect a vessel’s righting energy.

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

Questions for discussion

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Comromised Stability… operating practices and stability

Is it ever possible to single out any “one” factor that wasthe cause of a fishing vessel stability incident? An analy-sis of a fishing vessel capsize or marine incident almostalways identifies a sequence of events that led up to theoccurrence. It is also usually apparent that if any one ofthe events had not happened, the incident may not haveoccurred.

For example:“The watertight integrity of the main deck was compro-mised by the ineffective gaskets of five flush-fitting manholecovers, which resulted in extensive downflooding, a markedincrease in after trim, and reduced freeboard.” (TSB Report No. M02W0147)

“The weathertight doors from the main deck to the accom-modation area and the engine-room were secured in theopen position, compromising the watertight integrity of thevessel. This allowed shipped seawater to downflood intothe hull.” (TSB Report No. M97W0236)

“The vessel was unprepared for the open sea. The hingedtransom bulwark was left open and the hatch covers werenot secured.” (TSB Report No. M91W1075)

Stable boats have the potential to become unstable as aresult of inadequate maintenance and imprudent operat-ing practices. A major fishing vessel insurer has claimedthat their findings indicate maintenance and operationalissues are frequently the “proximate” factors that lead toa vessel becoming unstable and capsizing. What thismeans is we do not read headlines in the paper saying“unstable boat causes hatches to leak”.

With this in mind it is important to focus our attention onwhat we mean by maintenance and operating practicesas they relate to vessel stability.

The routine maintenance and safe operating practices onyour vessel may not be exactly the same as those foranother vessel, but they all serve the same purpose.That purpose is to eliminate all of the possible “one”things that could start a sequence of events that mightlead to a capsize. This means knowing all the areas onyour vessel and the fishing operations that have thepotential to make your vessel unstable.

You don’t ever want to have an incident at sea where inretrospect you say to yourself “if only I had checked tobe sure the ___________________”. Whatever answeryou put in the blank is probably the “one”.

For fishing vessels that have a stability book it is critical-ly important that the skipper consult the book and followany operating instructions that the naval architect hasspecified for the vessel. If you don’t have a stabilitybook with specific instructions, you should draft yourown operating practices in order to maintain adequatestability throughout each fishing trip.

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At no time should the port of starboard cargo hatch be leftopen at sea. These hatches must be secured watertight.They may be used in protected waters, but must be securedbefore returning to sea.The access door to the accommodation must be kept closedat sea. It may be used for going into and out of the accom-modation, but otherwise must be kept closed.All weights in this stability booklet are considered to be onthe centre line of the vessel. Care and attention to keepingweights centred, and minimizing a list condition must beadhered to.Fuel tanks and water tanks are considered to be separatetanks. To this end only one tank of each can be in operationat any one time. Failure to do so (i.e. cross connectionopen) may result in non-compliance with the regulations

The Wreck of the Edmund Fitzgerald, Gordon Lightfoot (1976 Moose Music Ltd.)“The captain wired in he had water comin’ inand the good ship and crew was in periland later that night when ‘is lights went out of sightcame the wreck of the Edmund Fitzgerald”

Instructions given in the “Trim And Stability Book” for the F.V. Summers Only:

•

•

•

•

49

List all the areas on your vessel that have the potential tobe the “one” factor and what maintenance and operatingpractices can eliminate the possibility of the “one” happening. The list you create can be the basis for yourvessel’s maintenance and stability instructions thatshould be posted and all crew familiar with.

Activity Sheet... find your“one”

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Which came first, the chicken or the egg? And how doesthis relate to events leading up to a fishing vessel stabilityincident?

Some skippers use checklists to stay on top of mainte-nance and operations. Why are checklists a good tool,and what are the limitations of checklists?

If you have ever had a “near miss” in terms of stability,what was the one thing that you would attribute it to?

The folks that analyze marine accidents and conductresearch say that 80% of occurrences can be attributed to“human error”. What do you think human error means inthe context of commercial fishing operations?

What are three things about stability that you couldalways ask yoursef when you commence fishing operations or before traveling?

What impact on fishing operations and safety do youthink fatigue has?

Many skippers use the “feel” of their vessel as an indica-tion of stability. Do you think this is a good measuringstick? Why or why not?

If you are a crewmember and don’t like the “feel” of the vessel, how would you present your concerns to the skipper?

1.

2.

3.

4.

5.

6.

7.

8.

Questions for discussion

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Lessons Learned

The Fishing Vessel Stability – Make it your Businesshandbook has explained fundamental stability principlesthat should be central to your everyday reality whenmaking any decisions that affect your vessel’s opera-tions. The handbook has profiled survivor stories andfindings from TSB Reports because lessons learned fromthe past can carry a powerful message into the future.

One of the most documented and unforgettable losseswas the capsizing of the Cap Rouge II on August 13th,2002 off the Fraser River in British Columbia. This losswill continue to be a resounding wake-up call to regula-tory bodies and everyone in the commercial fishingindustry as it is a stark reminder of several lessons to belearned.

While the TSB Marine Investigation Report (M02W0147)outlines findings and recommendations regarding theloss of the Cap Rouge II, an independent investigationinto the capsizing was also conducted by Robert AllenLtd., Naval Architects and Marine Engineers at therequest of the Workers’ Compensation Board of BC. Notonly does the Robert Allan Report make it clear that thedesign, construction and operation of a fishing vesselare a shared responsibility, it also identifies specific fac-tors that led to the loss of the Cap Rouge II and summa-rizes some key lessons to be learned.

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lesson learned:No fishing vessel should have holds that cannot all befilled and still meet appropriate stability standards.Holds which are proven too large to meet this criteriashould be foamed in to prevent any possible ingress ofwater or the addition of excessive cargo.

The Cap Rouge II was loaded deeply in the water reduc-ing its dynamic stability in fairly severe sea conditions.

lesson learned:There must be a reasonable amount of freeboard in anyload condition to ensure both good dynamic stabilitycharacteristics and the minimization of water on deck inpoor weather conditions.

The aft fuel tanks on the Cap Rouge II were cross-con-nected and open allowing fuel to migrate from one sideof the boat to the other.

lesson learned:Fuel tank cross-connections should not be open whentraveling to avoid fuel migration under other heelinginfluences.

The Cap Rouge II was loaded with a large trim by the stern.

lesson learned:A heavily trimmed attitude reduces the dynamic stabilitycharacteristics of most vessels, and should be avoided.

Lessons Learned... Cap Rouge IIThe tragic loss of the Cap Rouge II could unfortunatelyhave been avoided if a few simple rules of vessel loadingand stability had been better understood and implemented. The vessel’s hazardous conditions and resulting lessonslearned are outlined below as a reminder and guidance toother fishing vessel owners and operators.

A series of gear modifications were made to the Cap Rouge II, virtually all of which impacted negatively on the vessel’s stability by adding weight and raising thecentre of gravity.

lesson learned:The impact of structural and outfitting changes to anyboat must be closely monitored to determine that theirimpact on the vessel’s stability characteristics are notoverly detrimental to the vessel’s safety.

The Cap Rouge II was carrying a net which was too largeand heavy for the vessel, impacting very negatively on thevessel’s trim and stability. In addition, the net drum hadbeen raised to facilitate loading fish under the net, furthereroding initial and dynamic stability.

lesson learned:The size of net and the position of the drum must be carefullyconsidered for their impact on the stability of the vessel.

The holds on the Cap Rouge II were too large to be safelycarried on a boat that size. Filling all the hold and fueltanks would cause the Cap Rouge II to sink.

1.

2.

3.

4.

5.

6.

53

The gaskets on the manholes accessing the fish holdsand the lazarette on the Cap Rouge II were found to bein poor condition permitting leakage into those spacesunder water pressure from above.

lesson learned:The condition of all manhole (and door) gaskets shouldbe reviewed regularly and gaskets should be replaced ifthere is any evidence of deterioration. Hose testingshould be performed to verify gaskets are effective.

The skiff contributed to the loss of GM of the Cap RougeII by reducing GM and by exerting a starboard heelingmoment.

lesson learned:Towing arrangements for skiffs should be carefully con-sidered such that the load exerted on the towing vesselis both minimized and kept low on the centreline of thetowing vessel.

The two aft holds of the Cap Rouge II were only partial-ly loaded permitting a large free surface effect whichreduces initial and dynamic stability.

lesson learned:Whenever possible, fish-holds should either be emptyor pressed fully to the top to prevent the migration ofliquids in the holds, and the associated free surfaceeffect on stability. Inherent in this recommendation isthe assumption that the vessel has sufficient buoyancyand stability to support full holds.

You are a TeacherMost commercial fishermen have a stability story to tellthat is as important a lesson as theoretical knowledgeabout fishing vessel stability. Your stories are importantbecause they are real and told by your authentic voice asa commercial fisherman. Tell your stories, listen andlearn from one another. Commercial fishing is yourindustry and you have a strong voice in the developmentof a safety culture.

7.

8.

9.

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At the beginning of this course you wrote down a ques-tion about stability. What is the answer?

You are the author of this final chapter. What are thelessons that you have learned and will take back to yourvessel?

What is the most significant thing you have learned fromthis stability handbook or from the course?

The introduction suggested that a safety culture can befostered from lessons learned. Do you think this is possible? Why or why not?

1.

2.

3.

4.

Questions for discussion

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Activity Sheet... safety check

Make a list of the Fish Safe Stability Checks

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References and Credits

Illustrations, pages 19-21: Reproduced with permission from Transport Canadafrom publication TP8161. An Introduction to FishingVessel Stability. Cat. No. T31-60/1987. ISBN 0-662-5212-3

Hydrostatic Curve Illustration, page 22: Adapted from D R Derritt. Ship Stability for Masters and Mates. Stanford Maritime Limited. Fourth Edition,1984. ISBN 0-540-073388

Illustrations used in Chapter 4 referenced from the NorthPacific Vessel Owners Association Vessel Safety Manual.Used with permission.

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Appendix: Regulations

Safety regulations within the fishing industry are governedby both 1) WorkSafeBC which has a provincial jurisdictionto oversee and regulate worker safety and 2) TransportCanada Marine Safety which has a federal jurisdiction toregulate vessel safety. Since vessel stability includesboth structural and operational considerations, there hasbeen some overlap between WorkSafeBC and TransportCanada Marine Safety in developing stability require-ments. As a result, WorkSafeBC and Transport CanadaMarine Safety are working together to ensure a practicalprocess for meeting the two regulatory requirements forstability.

WorkSafeBC (Workers Compensation Board of BC)

Implementing the Regulation

Part 24 of the Occupational Health & Safety Regulation ofWorksafe BC outlines the requirements of an owner andmaster in regard to stability. WorkSafeBC published aguideline for implementing the regulation as it relates tovessel stability.

In part it states:“ Vessel Stability – Owner and Master ResponsibilitiesThe responsibility for ensuring the vessel continues topossess stability characteristics that render it seaworthyunder all anticipated sailing conditions rests with the vessel owner. The vessel owner should limit vessel operations so that it does not operate in conditions thatwould render the vessel unstable. In addition, the ownershould undertake any necessary vessel modifications toensure no workers are put at risk by the possibility of the

vessel becoming unstable during anticipated operatingconditions. A vessel owner is also responsible forensuring that documentation describing vessel stabilitycharacteristics is readily available to crew members onboard the vessel” (see OHSR s. 24.72(b)).

The vessel master is responsible for ensuring that thefishing vessel is capable of safely making the voyageplanned, with due consideration being given to the sea-worthiness and stability of the vessel (see OHSR s. 24.76). The master should refer to the vessel stabilitydocumentation provided by the owner in accordancewith OHSR s. 24.72(b) in making this assessment. A copy of the documentation setting out the vessel'sstability characteristics must be readily available on thevessel for reference by master and crew (see OHSRs. 24.72(b)).

Enforcing the Regulation

When conducting inspections and investigations, Boardofficers will evaluate whether the vessel has been sup-plied with meaningful and clear vessel stability docu-mentation.

Prevention Policy R24.70-1 describes the process that aboard officer will follow if they encounter a vessel wherestability may be a concern:“Where a Board officer considers that a vessel is clearlyunseaworthy, he or she will make an order to correct thesituation. Where the officer has a concern over seawor-thiness but is not sure, and the vessel is over 15 tons,the officer may require production of the vessel's

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Canada Steamship Inspection certificate issued underthe Canada Shipping Act. If no certificate is available, theofficer may order that one be obtained. Where the vessel is less than 15 tons, the officer mayconsult with the Canada Coast Guard [now TransportCanada Marine] for advice as to the seaworthiness of thevessel and whether applicable federal regulations havebeen complied with. The officer may order that a surveybe conducted by a marine surveyor, architect or engineerif he or she considers that there is a serious question asto the seaworthiness of a boat.

Where an officer has reasonable grounds to believe thata vessel's lack of seaworthiness presents an immediatedanger to its crew, the officer may issue a stop workorder (see Workers Compensation Act s. 191)requiring anassessment of the vessel's stability and work undertakento the vessel to ensure its stability in accordance with theassessment.”

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Transport Canada Marine Safety Transport Canada is responsible for establishing stabilitycriteria, as well as determining which vessels are requiredto meet those criteria by completing an incline test.

Transport Canada, however, is currently in the process ofCanada Shipping Act (CSA) 2001 Regulatory Reform. The Small Fishing Vessel Inspection Regulations, underCSA 2001 will be replaced by the more comprehensive

Fishing Vessel Safety Regulations.

Some basic features of the proposed Fishing VesselSafety Regulations include:Vessel sizes will be expressed in units of length ratherthan tonnage.Equipment carriage requirements to be determined byrisk management principles, the greater the risk themore stringent the requirements. Carriage requirementswill be based on voyage classes rather than vessellengths.The hull of every fishing vessel shall be marked to indicateits maximum permissible operating draft.Every fishing vessel shall be subject to an assessment ofits stability. It is proposed that a simplified stabilityassessment for vessels under 15 meters may be substituted, except in higher risk cases.

The current Small Fishing Vessel Inspection Regulationsonly require that fishing vessels over 15 gross tonnesengaged in the herring or capelin fisheries undergo aninclining test and carry a stability book. As noted above,it is anticipated that stability assessments will beextended to a wider range of fishing vessels.

A lengthy public consultation process has been carriedout with regard to the proposed Fishing Vessel SafetyRegulations and the preliminary Stability Standard forSmall Fishing Vessels under 24 metres in length, as wellas other proposed regulatory changes under CSA 2001.

CSA 2001 also includes proposed Marine PersonnelRegulations that address certification requirements forcommercial fishermen.

In support of CSA 2001 Regulatory Reform that will affectcommercial fishermen, Transport Canada has been clearthat an essential component is awareness programs andeducation.

Transport Canada has funded the development of theFish Safe Stability Education Program in order to providea national education program for fishermen.

•

•

•

•

For more detailed information on regulations, policiesand guidelines:www.worksafebc.comwww.tc.gc.cawww.fishsafebc.com

TransportCanada

TransportsCanada

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Do you think regulations are a necessary toollike speed limits on the highway?

Why do you think regulations do or do not work?

Why do you think we have regulations on stability?

What would make regulations more effective?

1.

2.

3.

4.

Questions for discussion