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APPEN

DIX1:MEASUREMENTSOFBRACKETFORTHEHANDRAIL

ANDC

ATWALKACCORDINGTOANTHROPO

METRYOFTHE

FISHE

RMANINMEXICO.

92

60

Measuresincm

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APPENDIX2:MESHDIMENSIONSANDNETPANEL

1.Thesizeo

fthemeshwasdefinedonthebasisofr

ecommendationsby

Beveridge(

1996).Thelargestmeshsizeandthinnesttwinediameterpossible

waschosen.

Thesmallerthemesh,thegreatertheprojecte

darea,whichcauses

increasedcurrentloads,decreasedwaterflowthroughthe

cagesandincreased

fouling.

Withtheminimum

sizeoffishinthestocking,theformulaof

Fridmanforgillnetwasappliedtoknowapproximately

thesizeofmeshfor

trapthisspe

ciesandwiththisdata,toreducethemeshsize.

OM=LfK

-1

(Fridman,

1986)

Where:

OM:meshopening(mm);

Lf:averagelengthoffishonewantstocatch(mm);

K:coefficientaccordin

gthespecies;

K=5forlongthinfish;

K=3.5

foraveragedsh

apedfish(neitherverythicknorthin),thisisthecasefo

rBlackSnook;

K=2.5

forverythick,wideorhighshapedfish;

2.Theareaof

thenetpanelwascalculatedastheperimeterofthecylindricalbag

(L)timesd

epth(H).Primaryandsecondaryhangingratios(E1andE2)of

0.707.

The

numberofstretchedmeshes(N

sm)andthenumberofrigged

meshes(N

rm

)forthelengthandheightofthepanelofnetwascalculatedwith:

Nsm=LOM-1

(forthelength)

(Prado,1990)

Nsm=HOM-1

(fortheheight)

Nrm=N

smE1-

1(

forthelength)

(Prado,1990)

Nrm=N

smE2-

1(

fortheheight)

3.Thesurface

coveredbythenetting(S:m

2)wascalculated

using:

S=E1(1-E12

)LHOM2

(Prado,1990)

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APPEN

DIX6:EFFECTIVEFLOTATIONFORC

EOFTHECAGE

22.

Theeffectiveflotationforcesforacleanandfouledcage(F

c:kg)and(Ff:

kg)

weredeterminedas:

Fc=F

n-Wtw

Ff=F

n-Wtfw

23.

Theemergencyeffectiveflotationforcesforcleanandfouledcages(F

ec:kg)

and(F

ef:kg)weredeterminedas:

Fec=F

e-Wtw

Fef=F

e-Wtfw

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APPENDIX7:CU

RRENTFORCESAPPLIEDTOTHECO

MPONENTSOF

THECAGE

24.Tocalculatetheloadsofcurrentstothenetpanel(L

n:kg),

thecagebagareain

frontofthe

currentwastakentobeplanepanel,perpendiculartothecurrent

force.This

representstheworstpossiblesituationandmaximumload.

Inthis

designofth

eonefixedpointformoorings,onefaceofth

ebagwillbealways

infrontofc

urrents.

Theactualworkingarea(A

a:m

2)wascalculatedas:

Aa=lh

(Fridman,

1986)

Where:

l:Lengthofthenetting

orthemountedlengthofthemainmountingrope,

infa

cingthecurrent(m).

h:heightofthenetting

orthemountedlengthofthesidehangingline,infacingthecurrent(m)

Thenthefic

titiousareaofnetpanel(Af:m

2)wascalculate

das:

Af=A

a/E1E2

(Fridman,

1986)

Where:

E1andE

2:Primaryand

secondaryhangingratios,previouslydetermined.

Theprojectedarea(A

p:m

2)infacingthecurrentwascalculatedas:

Ap=2Af(d/2a)(1+kkd/2a)

(Fridman,

1986)

Where:

d:diameterofthemeshtwine;

a:lengthofthemeshbar;

kk:coefficientofthe

knot-area,

typicallyis10.1forsquare-knot,9.7forsingle-knotand14.8

for

double-weavers-kno

tnetting.

Finallythecurrentloadsinthenetpanel(L

n)werecalcula

tedas:

Ln=CdV

2 (A

p/2)

(Milne,1

972)

Knottedmaterials:

Cd=1+3.77(d/a)+9.37(d/a)2

Knotlessmaterials:

Cd=1+2.73(d/a)+3.12(d/a)2

Where:

Cd:coefficientofdrag

ofthematerial(dimensionless);

:massdensityofwater(kgs2m

-4);freshwater=100andseawater=105;

V:currentvelocity(ms-

1).

Thecurrentforcesincleannetting,

Cd

wascalculatedusingtheoriginal

measurementsofthemesh;forcalculatingloadsinfouled

netting(L

nf:

kg)the

twinethicknesswasincreased3times.

Forthecalculation

,thecurrentvelocity

was:0.75m

s-1

(~1.5knots)and,forsecurity,oneextremevelocityof1.0ms-

1

(2.0

knots);thiswasdoneforallthecomponentsofthe

cageaffectedbythe

current.

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APPEN

DIX8:WINDFORCESAPPLIEDINTHESUPERSTRUCTUREOF

THEC

AGE

29.

Theloadsofthewindinthesuperstructureof

thecage(L

w:kg)wascalculated

using:

Lw=0.0965AV

2 (B

oven,1968,citedbyBeveridge,1996)

Whe

re:

A:sumoftheareasofpartsexposedtothewind,-freeboard

netting,handrail,floats-,(m

2);

V:w

indvelocity(ms-

1).

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APPENDIX9:WAVEFORCESAPPLIEDTOTHECAGE

30.Tocalculatethewaveforcesactingonacagecollar,

thehorizontaland

verticalorbitalvelocitiesofthewaterparticles(:ms-

1)a

nd(:ms-

1)mustbe

known,(Beveridge1996).Thesecanbecalculatedas:

=

{{H

wcosd[2(z+d)/L

w]}/twsind(2d/L

w)}cos

=

{{H

wsind[2(z+d)/L

w]}/twsind(2d

/L

w)}sin

(MuirWood&Fleming1981,citedbyBeveridge1996)

Where:

Hw:waveheight(m);

d:depthofwater(

m);

z:variationfromm

eanwaterlevel(m);

Lw

:wavelength(m

);

tw:waveperiod(s);

:angleofwaverelativetothestructure()

AccordingtoMilne(1972),isunlikelytoexceed2ms

-1

inmostfishfarming

conditions,

andthusthisvaluecanbeusedfordesigning

purposesformarine

cages.Beveridge(1996),proposesthattheequationfor

calculatingthedrag

forcesexertedbycurrentsonnettingisapplicable.

The

forceexertedonthe

collarbyth

ewave(L

sw:kg)canbedescribedbyanequationsimilartothat

derivedfor

effectofcurrents:

Lsw=Kd

2

A

Where:

Kd:

dimensionlessconstant,similartoC

dfornetting,whosevaluedependofthematerialandshapeof

thecollar,

inthisc

aseforapproximatelycalculationscanbetakenthevaluesoftable9.

:massdensityofwater(kgs2m

-4);forseawater105.

:horizontalcomponentofwaveparticleorbitalvelocity;formarinecages2m

s-1;

A:areaofthecagecollarperpendiculartothewavetrain(m2).

Theverticalcom

ponentofwaveparticlemaximum

orbitalvelocity()is

approximately83%

ofthe,

(Wiegel1964,c

itedbyBeveridge1996).

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APPEN

DIX10:GENERALARRANGEMENTOFPARTS,DIMENSIONS

ANDM

ATERIALSOFTHEMOORINGANDANCHORSYSTEMSFORTHE

CAGE.

Measuresinm

Swivelalwaysin

tension

2.1tonsX3

PP24

PP26

PP40

PP40

14

14

14

2x34kgf

250kgf

250kgf

150kgf

~35

6

3

10

~6

10

400kgf

6

106kgf

Chain+swivel+rope

40kgf

Tubeofmoorings

PP24

10

6

9

RaisedropePA3

m

Raisedchain26

7m

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calc. cage