93426594 gz curves revised

8/12/2019 93426594 GZ Curves Revised

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GZ Curves

Let G move G1, Then it can be seen with a shift of CARGO, the Vessel will

Capsize Earlier

GZm!

GZ "a#

GZ "a#

G"

$eel

%ec &'()

RA*GE

+mmar-.

1(G" /oes not chan0e

( %ec2 a0e /oes not chan0e)(At 3 /e0 GZ /oes not chan0e

4(Vsl as a list 5GZ 63

&(GZ ma# is Re/ce/

7(An0le V5+ Re/ce/

'(Ran0e Re/ce/

8(Area n/er Crve Re/ce/

Remar2s.a! +hift of 9l2 Car0o

Vessel withthe shift of

car0o

An0le of

vanishin0

stabilit- : v5s

;nitial GZ



m1

0

0

Car0o

G

91! G" Re/ce/

! %ec2 a0e ;mmersion not Chan0e/

)! GZ at 3 /e0 is ne0ative

°

°

G G1 G G1

9 9 9

GZ *e0ative Re/ce/! GZ63 GZ6positive Re/ce/



Let G move to G1 then it can be seen on the vessel that the shift of the

9l2 car0o will Cap size earlier

9elow Graph illstrates that when the bl2 car0o is shifte/ earlier the

Vessel will capsize

GZm!

GZma#!

G"

G"

%ec2 a0e &'(& heel

RA*GE

+mmar-.

1! G" is re/ce/! %ec2 a0e remains the same

)! At 3° GZ is *e0ative

4! Vessel has a list GZ63

&! GZ ma# re/ce/

7! An0le of vanishin0 stabilit- re/ce/

'! Ran0e Re/ce/

8! Area

Remar2s.

;nitial GZ

An0le of

vanishin0stabilit-



Non Symentrical Icing

G1ice

"

G

<5L

<5L1

9

+mmar-.

1! G" re/ce/! An0le of /ec2 a0e immersion Re/ce/

)! GZ is *e0ative



Lets move G to G1 then it can be seen that the Vessel with a Non

symmetrical icing and heavy lift will capsie earlier

GZm!

An0le of vanishin0 stabilit-

;nitial GZ

GZ ma#

G"

%ec2 a0e &'()Summary!

1! G" is re/ce/

! %ec2 a0e is re/ce/

)! At 3° GZ is ne0ative

4! Vessel has a list GZ63



&! GZ ma# re/ce/

7! An0le of vanishin0 stabilit- is re/ce/

'! Ran0e Re/ce/

8! Area Re/ce/

"ilging of a side compartment

"

G <5L

<5L1

Ship side #ole

9

+mmar-.

1! Assme G" is re/ce/

! %ec2 a0e is re/ce/)! GZ is ne0ative



GZm!

;nitial GZ

GZ ma#

:v5s

G"G"

List Ran0e heel

+mmar-.

1! Assme G" is Re/ce/



! %ec2 a0e immersion re/ce/

)! At 3° GZ is *e0ative

4! Vessel as a list GZ63

Increasing $reeboard

"

G

9

9

G

9



=or > p to %ec2 a0e of the vessel with the Low free boar/ GZ6

=or > 9e-on/ %ec2 a0e immersion of the vessel with a

low freeboar/ GZ is increase/ , for a vessel with a hi0h

=reeboar/

The ;ncrease in the free boar/ , vessel will capsize later

Remar2s

G

<5L

91

9

%ec. %enote/ b- %ec2 a0e ;mmersion



An0le of V5+

GZm! Low =reeboar/

GZm!

G"

RA*GE

Observations.

1( G"6

( %ec ;ncrease/

)( At 3° GZ63

4( ?pto :°/ec of vsl with low =reeboar/ GZ6

&( 9e-on/ %ec vsl with Low freeboar/ G" ;ncrease/7( GZ ma# ;ncrease/

'( :° v5s ;ncrease/

8( Ran0e increase/

@( Area ;ncrease/

Remar2s.

1(1. show the effect of re/cin0 the =reeboar/



An0le of V5+

GZm! Low =reeboar/

GZm!

G"

RA*GE

Observations.

Observations.

1( G"6

( %ec %ecrease/

)( At 3° GZ63

4( ?pto :°/ec of vsl with low =reeboar/ GZ nchan0e/

&( 9e-on/ %ec vsl with Low freeboar/ G" Re/ce/

7( GZ ma# %ecrease/

'( :° v5s %ecrease/

8( Ran0e %ecrease/

@( Area %ecrease/

3531531



Contination of GZ crves

;ncrease in the 9eam

<5L

1! G" ;ncrease/

! %ec2 E/0e ;mmersion %ecrease/

)! GZ63

Remar2s.



<5L

=or> p to %ec2 e/0e of the Vessel with ;ncrease beam GZ

;ncrease/

=or > 9e-on/ the /ec2 e/0e On the vessel with positive

9eam GZ increase/



Let G move to 01 then it can be seen that the vessel with the

ive 9eam will Capsize later

+mmar-.

1! G" increase/

! %ec2 e/0e %ecrease/

)! At 3° GZ63

4! =or all:GZ increase/ , other than 3°

&! GZ ma#imm ;ncrease/

7! An0le of V5+ ;ncrease/

'! Ran0e ;ncrease/

8! Area ;ncrease/

Correcting a %ngle of Loll



1! G" *e0ative /ecrease/

! An0le of /ec2 e/0e ;mmersion %ecrease/

)! GZ is still ne0ative

a! GZ is *e0ative an/ increase/ b! GZ is *e0ative an/ %ecrease/



a! GZ ositive %ecrease/

b! GZ ositive ;ncrease/

Remar2s.



+mmar-



a! 1( G" *e0ative /ecrease/

( %ec2 E/0e ;mmersion %ecrease/

)( GZ *e0ative

4( =or > : loll GZ ne0ative increase/

&( At > 6loll GZ ne0ative

7( GZ ma#imm %ecrease/

'( Ran0e %ecrease/

8( : V5+ %ecrease/

@( Area %ecrease/13(Vessel has combine/ List 5Loll

b! 1( G" positive

( %ec2 E/0e ;mmersion %ecrease/ =rther

%ecrease/

)( GZ *e0ative ;ncrease/4( =or > : loll GZ ne0ative /ecrease/

&( At > 6loll GZ positive

7( GZ ma#imm ;ncrease/

'( Ran0e ;ncrease/

8( : V5+ ;ncrease/

@( Area ;ncrease/13(Vessel has combine/ List Onl-

G



" G

G

<5L

1! G" *e0ative

! %ec2 E/0e EBals6

)! GZ63

1! G" *e0ative

! %ec2 E/0e EBals6

)! GZ63

Remar2s.



G G

G

G G G

9 9 9

> : Loll >6Loll >Loll

a!GZ *e0ative a!GZ 6 a!GZ6 Dive %ecrease/

b!GZ positive ;nc b! GZ positive ;nc c! GZ positive ;nc



GZ

GZ

GZ

G"

G"

+mmar-.

1! G" *e0ative



! %ec2 e/0e 6

)! At° GZ63

4! Vessel has :loll! GZ63!

&! GZ ma#imm %ecrease/7! : V5+ %ecrease/

'! Ran0e %ecrease/

8! Area %ecrease/

1! G" ositive

! %ec2 e/0e 6)! At° GZ63

4! GZ ma#imm ;ncrease/

7! : V5+ ;ncrease/

'! Ran0e ;ncrease/

8! Area ;ncrease/

estion.1(<hat is the effect of waves on a vessel GZ crveF



=i0re 1 shows a vessel with a wave of appro#imate len0th

of the ship

<hen <L1 the wave has a crest at the mi/ ship an/ <Lhas the waves tro0hs at the mi/ ship

=i0re . shows Cross section thro0h the vessel at a,b an/

c

=i0re ) . +hows a plan view of the vessel with the

waterlines 1 an/ =rom which it can be seen there is a chan0e in the water

plane area as the wave mass moves alon0 the vessel

An increase in the water plane area wol/ 0ive a increase to

the 9"

;f we assme that the overall Central of 9o-anc- 9remains constant

Then " an/ $ence G" will increase

Grain Re0lations



Orals estion $i0hl-!

1. <ith the Ai/ of a sitable /ia0ram /escribe how compliance

with the Crrent Grain Re0lations is /etermine/F

%etermine from the 1st principalsF

+oltion. Compliance from the 1st principals is as =ollows

1.Complete a %raft srve- 6 /isplacement 6"5* from the

$-/rostatic tables!

(Complete a lla0e +rve- 6 the Volme of Grain 6 mass

volme5+=stora0e factor!

)(Calclate the mass 60 6Volmetric $eelin0 moment

4( Calclate 0 of the Vessel therefore we can fin/ G"5 3()m

&(Calclate the Total Volmetric $eelin0 moment

7(Calclate the Grain heelin0 lever at 3°

Lamb/a 6The Total Volmetric $eelin0 "oment V$"!

+tora0e factor +=! H %isplacement

'(Calclate the Grain heelin0 lever arm at 43



8(To calclate the Vessel GZ vale where GZ6*IG sin>

lot the vessel GZ crve an/ the vessels 0rain $eelin0

arm or lever!crve on the same a#is as shown followin0

GZm!

Grain $eelin0 arm

$or Compliance.1. G" 3()3m

( > 1°

)( The area bon/e/ b- the GZ Crve , the 0rain heelin0

arm crve an/ the lesser of

1(A vertical Line Thro0h AVLT! 43°(AVLT the an0le of /own floo/in0

)(AVLT the ma# /ifference in or/inates , this area shol/not be less than 3(3'&mRa/



4(Vessel mst be ?pri0ht prior to /epartreNote ! &he 'aster must be able to prove Compliance

from the 1st principals

November ())*

S+% ,-amination.

+uestion (!

A vessel is to loa/ a car0o of 0rain stowa0e factor 1(&' m)5t!

;nitial %isplacement 7433t(initial G 7(48m

All =ive $ol/s are to be loa/e/ fll of 0rain

The TIween /ec2s are to be loa/e/ as follows. *o1 T% =ll

*o T% art fllI?lla0e 1(&m

*o) T% art =llI?lla0e )(33m *o4 T% =ll

The stabilit- %ata 9oo2let provi/es the necessar- Car0o

compartments /ata for the vessel

a! <ith the ai/ of the ma#imm permissible Grain heelin0

"oment table incl/e/ in the stabilit- /ata boo2let ,/etermine if

the vessel complies with the minimm criteria specifie/ in the

;nternational 0rain co/e;"O!

b! Calclate the +hips appro#imate an0le of list in the event

of 0rain shiftin0 as assme/ b- the international Grain co/e

;"O!

Solution!6+tora0e factor. +(=61(&'!



6V$". Volmentric heelin0 "oment

Volume 'ass

/V.S$0

g 'oments

/'ass - g0

V#'

7433 7(48 414'(

1( 1& 1413(8 &(38@ '1'@(77 43@(&

( 47' @'&('@ 4(@4' 14'1() 184(@

)( 1'4 113@(&& 4(@43 &481(1' 4'&(4

4( )4'4 1(') 4(@&3 13@&)(31 @13(4

&( 73& 17&@() 8('74 14&41(4@ 4&4(@

1( 17@& 13'@(7 11(&7 11&(3 )&(4( 1&73 @@)(7) 13(7&) 13&8&(14 174

)( 8&8 48(83 13()) 4@8)(@4 )))@

4( 17'4 1377(4 13(&7' 1177(@& 734(4

&2&%L 1343)566 144447583 368(53

There fore 06 "oments 61))))7('3 6 7(88m

"ass 1@)@3(44

There =ore 067(8m

Vessel Actal $eelin0 "oments 6 Total V$"5+=

6@4'(@51(&'

6 73))(' tns 5m

I=or a /isplacement of 1@333 an/ 1@&33 an/ for a G of 7(8 an/

7(@ ,the ma#imm permissible heelin0 moments is not less than

'1&' tns5mts

The vessels actal heelin0 moments 73))(' tns5mtrs, There fore

is meets the reBirements as per Table

9t the Vessel e#cee/s the +mmer loa/ line %isplacement of1@337 Tns



=rom the $-/rostatic table.

=rom the /isplacement of 1@)@ tns an/ 1@&') , the " variesfrom 8(&3 to 8(43 ,meets the vessels G of 7(8'm

There fore the Vessel G" is Greater than the reBire/ 3(3)G"

An0le of Lists 6

Actal $eelin0 moments 1°

"a#imm permissible heelin0 "oments

Gatherin0 ;npts from the h-/rostatic table an/ 9- interpolatin0

the same

1@)@3(4& I1@333 6 )@3(4& 6 3('8

1@&33(33 I1@333 &33

There fore 0 for 7(8 an/ 7(@ m

7(8 J K'''3I'&''! # 3('8D'&''6'''(&4

7(@ J K'))@I'1&'! # 3('@D'1&'6'@8(@7

There fore 0 6 7(8' I7(83 6 3('

7(@3I7(83

There =ore $eelin0 moments

Obtaine/ from initial 0

from the Table



hm6K'@8(@7I'''(&4!#3('D'''(&4 6'4'(& tns5m

An0le of Lists 6

Actal $eelin0 moments 1°

"a#imm permissible heelin0 "oments

73))('

# 1° 6@('4°

'4'(&

List63@°44

*ovember 338

estion +A



( A vessel is to loa/ a car0o of 0rain stowa0e factor 1(7&m)5t!

;nitial %isplacement 733t , initial G 8(&3m

All five hol/s are to be loa/e/ fll of 0rain

The Tween /ec2s are to loa/e/ as follows

*o1 T% III=ll

*o T% IIIIEmpt-

*o) T% IIIIart =ll J?lla0e 1(&3m *o4 T% IIII=ll

The stabilit- %ata 9oo2let provi/es the necessar- Car0oCompartments /ata for the vessel

?sin0 the * tables to constrct a GZ crve ,/etermine whether

the vessel complies with the minimm Criteria +pecifie/ in the

international Grain Co/e ;"O!



Gi/ance to srve-ors for win/ a0e for containers

1(%escribe $ow compliance with the 0i/elines is

/etermine/ incl/in0 how the effect of 0stin0 win/s is

consi/ere/ F

QuickTimeª and a decompressor

are needed to see this picture.

=i0re 1( show,s a container vessel ,where C is the Centroi/

of the win/ a0e area an/ 9 is the Center of 9o-anc- ,the win/heelin0 "oment <$"!,applie/ to the Vessel is 0iven b- the



<in/ a0e Area # 48(& 05m # c b

1333

Gsts are Ta2en into accont b- "ltipl-in0 <$" # 1(&=or Compliance to the Gi/elines

a! lot the vessels Ri0htin0 moments M! as shown in =i0re

b! On the +ame A#is the win/ $eelin0 moments an/ Gste/

win/ heelin0 moments are shown

c! These lines are parallel to the H a#is

=i0re .

=rom =i0re is the an0le of statical stabilit- an/ mst not

be 0reater than 3(7& the /ec2 e/0e ;mmersion

1 is 1&° less

16I1&°

=or Compliance Area a! mst be less than or eBal to the area9 : b



*ote. Area A Represents the ener0- Applie/ to the Vessel,

thro0h a combination of 0sts an/ Rollin0

Area 9 represents the vessel Abilit- to absorb ener0- pto the

an0le of /own floo/in0

159hat is Syncronised :ollingF

+-ncronise/ rollin0 occrs when the natral roll perio/ of the

vessel is the same as the Enconter =reBenc- of the <ave+-stem

(59hat are the dangers %ssociated with it;

The %an0ers Associate/ with the s-ncronise/ rollin0 are as

follows

1( Capsize

( +trctral /ama0e

)( Loss of /ec2 car0o

4( +hift of car0o

&( ;nNr- to ersonnel

7( Crew /iscomfort lea/in0 to =ati0e

45,-plain how a vessel natural roll period can be %ltered

so that the vessel can continue on its previous course;

The =ollowin0 measre can be ta2en so that the vessel can

contine on its previos corse

a! Alter spee/ , if the waves are from the 9eam

b! Alter the Vessel natral Roll perio/

c! T 6



This is the formla for the vessel *atral roll erio/ , where is

the Ra/is of the G-ration an/ is /epen/ent on he position of the

mass relative to the center line ,so that if the mass are move/

otboar/ from the center lineChan0es in the G" also effect the Roll perio/

G" is /epen/ent on the position of mass relative to the 2eel

+o that the mornin0 mass /own will increase G", bt %ecrease

the Roll perio/

Syncronised <itching

159hat is Syncronised <itching

<hen the natral itchin0 perio/ is the same as the nconter

=reBenc- of the wave s-stem

(59hat are the damages associated with it;

1! +trctral /ama0e

! Loss of %ec2 Cra0o

)! +hift of Car0o

4! Crew %iscomfort

&! Other isses incl/e the /ama0es to the platein0 from the

stern

7! %ama0e /e to caviatation

'! %ama0e to the main "achiner- /e to C-clic loa/in0

8! %ama0e to the R//er late

459ith the %id of Suitable =iagrams ,-plain the

Corrections to be applied when converting from tabular

free board to assign $reeboard %s per load lines;

The tablar freeboar/ is fon/ from the tables of the loa/ line



Rles

The 1st correction is to be applie/ is the 9loc2 Co efficient

correction cb! ;s the abbreviation;f the Vessel cb! is 3(78 then the =reeboar/ is increase/

This is becase a hi0h CoIefficient vessel as less reserve/

9o-anc- as a precation to its n/erwater volme

Once this correction aa been applie/ the vessel achives a basic

=reeboar/

The ne#t correction is the Correction for the bow hei0ht

;f reBire/ , the freeboar/ is increase/ ntil the minimm 9ow

hei0ht is achive/

659hy is the 'a-imum =raft forward;

To maintain the "inimm bow hei0ht as reBire/ b- the loa/

lines

Sheer Corrections!

The vessel +heer is compare/ with that of a stan/ar/ template as



shown in fi0re 1,if there is an e#cess sheer .then the freeboar/

ma- be re/ce/ ,this is becase the e#cess sheer provi/es

a//itional bo-anc- an/ protection to the /ec2 an/ vice versa

+per strctre J Trn2in0

A correction for sperstrctre Trn2in0 ma- be /one if the

sperstrctre trn2in0 meets the reBirements of the loa/line

re0lations for the re/ction in freeboar/ then the freeboar/ ma-

be re/ce/

This is becase the sperstrctre

Trn2in0 provi/es a//itional bo-anc- an/ the protection to the/ec2

This is calle/ the /ec2line Correction

=i0re 1



A correction for the /ec2 a0e is applie/ sch that the

freeboar/ is re/ce/ to ta2in0 into accont

The /ifference between the /ec2 a0e an/ the actal hei0hts

of the /ec2

%ec2 corrections

;f C5% :18

The freeboar/ is increase/ :this is becase the vessel with a

0reat /epth will have a reserve bo-anc- an/ there fore sin2

/eeper in the event of 9il0in0At this point the vessel is 0iven is calle/ assi0ne/

=reeboar/

Ro Ro =erries

&( %iscss the stabilit- problems associate/ wit the %esi0n

an/ operations of a convectional Ro Ro vehicle ferr-F

> =esign Considerations.

1( *ee/ for the bow /oors compromises water ti0ht inte0rit-

of the ship (inner an/ oter /oors fitte/( <i/e open Car /ec2 ma- reslt in sever loss of Gm in the

event of water on the %ec2 ,?se of rectrables transverse

9l2hea/s ,sponsors ,lar0e scppers to /rain the water into

heavil- Compartmental 9il0es

)( *ee/ to operate in shallow waters ReBires small /raft so

limitin0 9 an/ re/cin0 stabilit- ,increasin0 beam

increases 9" hence increases stabilit-4( *ee/ for vessel to remain pri0ht /rin0 loa/in0 reBires an



atomatic Transverse 9allast s-stem

&( ?se of active stabilizers to re/ce roll an0le an/ increases

roll perio/

2perational Considerations

1(*ee/ to wei0h all heav- 0oo/s an/ estimate wei0hts of the

passen0ers vehicles to pro/ce a loa/in0 pro0ram an/ estimate

the vessels final G", vehicles Carr-in0 $arzar/os Goo/s are

separate/ from the remain/er for the vehicles

( %rin0 the loa/in0 Transverse ballast s-stem is se/ to 2eep

the vessel ?pri0ht,this ma- be atomatic or manal

)( Once Vehicles are loa/e/ ($GV are lashe/

4( %rafts "ar2s are rea/ an/ the ships %isplacement fon/

from the $-/rostatic Table ,if there is a sbstancial /ifference

in the /isplacement of the $-/rostatic tables an/ that

calclate/ from the loa/in0 plan ,then the a//itional mass is

consi/ere/ Locate/ on the hi0hest %ec2 for prpose of

calclatin0 the mo/ifie/ G"

&(There mst be a s-stem of reportin0 to ensre that the bow

/oors are close/ prior to sailin0

7( The master mst be aware of possible ;nteraction Effects

with the other vessels on leavin0 an/ enterin0 the harbor

'( The master mst be ma/e aware of the possible heel /e to

the trnin0 at hi0h spee/ with the possible shift of vehicles

93426594 gz curves revised

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