Part B Paper 1 General Ship Knowledge (3 hrs, 50% pass)

-Continue function 1
Ship Stability
1. Working knowledge and appliation o! stability, trim, stress tables, diagrams and
stress calculating equipment.
2. "nderstanding o! the !#nda$entals o! watertight integrity%
3. Stability criteria% &#ll !or$ Coefficients, displacement, deadweight, lightweight%
Curves and tables o! displae$ent and 'P(% Load Line $arkings% ensity, !elative
ensity, "rchimedes principle, flotation% )!!ets o! density o! water on draught and
freeboard% #$", $"% 'he $arine hydrometer and its #ses% %uoyancy, reserve
buoyancy, partial loss of intact buoyancy%
&. 'ransverse stability* +e!initions o! ,(,, ,%,, and ,),% *quilibrium positions o! ,G,, ,B,,
and ,-,% !ighting lever and righting moment%
+. Stability information* Sta.ilit/ in!or$ation s#pplied to ships% "ses o! hydrostatic data
!or sta.ilit/, dra#ght and tri$% "dding and removing weights% #ree surface effect,
danger o! slak tanks%
1% +e!initions
i% Weight is a !ore and is the prod#t o! $ass and aeleration d#e to earth0s
gra1it/% )2pressed in 3ewtons (3)%
W 4 - 2 5
ii% -ass e2pressed in Kilogra$s (Kg)
iii% 6ore the prod#t o! $ass and aeleration
i1% -o$ent the prod#t o! !ore and distane
-o$ent 4 weight 2 distane
1% 7 7ength
1i% B Breadth
1ii% + +epth
1iii% d +ra#ght
i2% +isplae$ent the weight o! 1essel 4 the $ass o! water displaed
+isplae$ent 4 8ol#$e 2 densit/
2% +eadweight
+eadweight 4 6#ll loaded displae$ent light displae$ent
2i% +ensit/ $ass per #nit 1ol#$e e2pressed as kg per #.i $eter
2ii% Spei!i gra1it/ (SG) 9 :elati1e densit/ (in Kg per #.i $eter)
SG ; densit/ o! s#.stane 9 1000
2iii% 5rhi$edes0 Priniple% When a .od/ is wholl/ or partiall/ i$$ersed in a !l#id% <t
appears to s#!!er a loss o! $ass e=#al to the $ass o! the !l#id it displaes%
2i1% :eser1e .#o/an/ (:B) the watertight 1ol#$e a.o1e the waterline%
:B (in -
3
) 4 'otal 1ol#$e 1ol#$e o! displae$ent
21% (enter o! B#o/an/ (B) the geo$etrial enter o! the #nderwater 1ol#$e and
the point thro#gh whih the total !ore d#e to .#o/an/ $a/ .e onsidered to at
1ertiall/ #pwards% 'he position o! B $a/ .e al#lated ./ Si$pson0s r#les
21i% 8aria.le i$$ersion h/dro$eter% 5n instr#$ent .ased on the law o! 5rhi$edes to
deter$ine the densit/ o! li=#ids% <t is $ade o! non orrosi1es $aterial and onsists
o! a weighted .#l. with a narrow retang#lar ste$ whih arries a sale !or
$eas#ring densit/% 5s densit/ o! water inreases, the h/dro$eter will !loat higher,
and a larger densit/ sale will .e read%
21ii% (enter o! Gra1it/ (G) the point o! a .od/ at whih all the $ass o! the .od/ $a/
.e ass#$ed to .e onentrated% <t is also the point thro#gh whih the !ore o!
gra1it/ (e=#als the weight o! .od/) at 1ertiall/ downward% <t is also the point
the .od/ wo#ld .alane% When a weight is s#spended, its G is onsidered to .e at
the point o! s#spension%
21iii% -etaentre (-) ; 'he point where the 1ertials thro#gh the enter o! .#o/an/ at
> onse#ti1e angles o! heel interset
2i2% 7ongit#dinal (enter o! 6lotation (6) or (7(6) 'he point at whih the ship tri$,
is the enter o! gra1it/ o! the ware plane area% 'ri$$ing $o$ents are taken a.o#t
6, where rotation takes plae%
22% 7ist ;
tan ?4 GG
1
9 G-
22i% G- <nitial 'rans1erse -etaentri &eight% When G is .elow -, G- is positi1e%
22ii% G-
7
7ongit#dinal -etaentri &eight
G-
7
9 GG
1
4 7 9 hange o! tri$
22iii% G@ :ighting le1er% 'he perpendi#lar distane .etween enter o! gra1it/ (G)
and the 1ertial thro#gh the enter o! .#o/an/ (B)% &owe1er !or large angle o!
heel, !ore o! .#o/an/ no longer at 1ertiall/ #pwards thro#gh -%
G@ 4 G- 2 sin ? A!or s$all angle o! heelB
G@ 4 (G- C 19> B- tan
>
?) sin ? A!or angle whih dek edge i$$ersed
3ew G@ 4 Dld G@ C GG
1
sin ? ASta.ilit/ #r1e, C when 1sl KG E ass#$ed KGB
22i1% K- ; &eight o! the trans1erse $etaentre a.o1e the keel% <t depends #pon the
#nderwater !or$ o! ship
221% KG &eight o! enter o! gra1it/ a.o1e keel%
6inal KG 4 6inal $o$ent a.o1e keel 9 6inal displae$ent
221i% Shi!t o! enter o! gra1it/ (GG
1
) in $eter% 'he G o! a ship will $o1e parallel to the
shi!t o! G o! an/ weight $o1ed within the ship%
GG
1
4 6inal $o$ent a.o#t enterline 9 6inal displae$ent
221ii% KB &eight o! enter o! .#o/an/ a.o1e keel
6or .o2 shapeF KB 4 (19>) dra!t
6or shipF B .elow enterline 4 (193) 2 (d9> C 89WP5)
221iii% -o$ent o! Statial Sta.ilit/ $o$ent taken a.o#t G to ret#rn the ship to the
initial position when inlined ./ e2ternal !ore
-o$ent o! Statial Sta.ilit/ 4 W 2 G@
22i2% Waterplane (oe!!iient ((w) ratio .etween the waterplane area (5) and the area
o! the ir#$sri.ing triangle%
(w 4 5 9 (7 2 B)
222% Blok (oe!!iient ((.) ratio .etween the #nderwater 1ol#$e (8) and the
1ol#$e o! ir#$sri.ing .lok%
(. 4 8 9 (7 2 B 2 d)
222i% Pris$ati (oe!!iient ratio .etween the #nderwater 1ol#$e (8) and the 1ol#$e
o.tained !ro$ the prod#t o! the 7BP and the #nderwater are o! the $idship
setion (5$)% <t indiates a 1essel0s shape at the ends%
(p 4 8 9 (7BP 2 5$) 4 (. 9 ($
222ii% -idship oe!!iient ratio o! the trans1erse area o! the $idship setion to a
retangle ha1ing the sa$e .readth and depths
($ 4 5$ 9 B 2 d
222iii% 'onnes per enti$eter i$$ersion ('P() the $ass (in tonne) to .e loaded 9
disharged to hange the $ean dra#ght in salt water ./ 1 $%
'P( 4 (Water Plane 5rea 2 densit/) 9 100
222i1% 6resh Water 5llowane hange in $ean dra!t when ship sail !ro$ SW to 6W
6W5 4 (Sea Water displae$ent) 9 (G 2 'P()
2221% +ok Water 5llowane hange in $ean dra!t when ship sail !ro$ SW to +W
+W5 4 6W5 2 (10>5 +ensit/ o! +W) 9 >5
2221i% -o$ent to hange 'ri$ ./ 1 (enti$eter
-('( 4 (W 2 G-
7
) 9 (100 2 7)
2221ii% Bodil/ sinkage or rise
Weight 9 'P(
>% )!!et o! densit/ on dra!t% When densit/ o! water hange, $ass o! water displaed will not
.e hanged% So the dra!t $#st hange to displae the sa$e $ass o! water%
i% Bo2 shaped 1essel
3ew dra!t 4 Dld dra!t 2 Dld densit/ 9 3ew densit/
ii% Ship shaped 6W5
3% 7oadline $arking all lines is >5 $$ thik
i% +raw a irle o#ter dia$eter 4 300 $$, enter on s#$$er loadline
ii% (enter o! irle 1ertiall/ C stat#tor/ !ree.oard 4 dek line
iii% +ek line 4 horiHontal 300 $$ long
i1% &oriHontal line di1iding the dis 4 G50 $$ long
1% (enter o! dis horiHontall/ right 5G0$$ draw a 1ertial line
1i% <n line with the horiHontal line o! the dis, draw horiHontal line (>30$$) at the
right hand side o! the 1ertial line, na$ed ISJ, o! whih the #pper edge is the
s#$$er dra!t%
1ii% ISJ line 1ertiall/ C 6W5 4 I6J line on the le!t o! 1ertial line
1iii% 'he se=#ene 4 '6, 6, ', S, W, W35
G% )=#ili.ri#$
i% Sta.le e=#ili.ri#$ ; 5 ship is said to .e with positi1e sta.ilit/ i!, when inlined
!or s$all angle o! heel, she tends to ret#rn to the initial position% 'he entre o!
gra1it/ (G) $#st .e .elow the $etaentre (-), i%e% a positi1e initial $etaentri
height (G-)%
G
-
B#o/an/ 6ore
Weight (W)
B
1
B
@
When ship is inlined to a s$all angle, position o! G re$ains #na!!eted ./ the
heel and !ore o! gra1it/ at 1ertiall/ downwards thro#gh G% 'he B $o1es o#t to
the low side to B
1
to take #p the new enter o! gra1it/ o! the #nderwater 1ol#$e%
'he !ore o! .#o/an/ at 1ertiall/ #pwards thro#gh B
1
and -% 'ake $o$ent
a.o#t G, a $o$ent alled $o$ent o! statial sta.ilit/ (4 W 2 G@) is to ret#rn
the ship to the #pright% G@ is the righting le1er and is the perpendi#lar distane
.etween the G and the 1ertial thro#gh the B% 5t a s$all angel o! heel (15 ), G@
4 G- 2 sin ?%
ii% "nsta.le e=#ili.ri#$ When a ship is inlined to a s$all angle tends to heel
o1er still !#rther, she is in #nsta.le e=#ili.ri#$% 'he ship $#st ha1e a negati1e
G-, i%e% G is a.o1e -% $o$ent o! statial sta.ilit/ (W 2 G@) is a apsiHing
$o$ent%
iii% 3e#tral e=#ili.ri#$ G oinides with -% <! ship inlined, she tends to re$ain at
that angle o! heel% G@ 4 0% -o$ent o! statial sta.ilit/ 4 0%
i1% (orreting #nsta.le e=#ili.ri#$
a) Weight loaded .elow G o! ship 9 disharged a.o1e G o! ship
.) :e$o1e 6ree S#r!ae )!!et
) 7ower the weight in the ship
5% 5ngel o! loll
i% 3egati1e initial G-
ii% 5s angle o! heel inreases, B $o1e o#t to the low side
G
B#o/an/ 6ore
Weight (W)
B
1
B
@
iii% <! B $o1es o#t to position 1ertiall/ #nder G, apsiHing $o$ent disappear
i1% 'he angle o! heel at whih this o#r is angle o! loll
1% G@ is Hero, G re$ains on enter line
1i% <! ship is heel .e/ond angle o! loll, B will $o1e !#rther and she will .e ret#rn to
angle o! loll
K% 6ree S#r!ae )!!et
i% Within a slak tank, G o! water shi!t when ship inline
ii% )!!eti1e G- red#ed ./ GG1 (G o! ship shi!t o!! enter line ./ GG
1
)
iii% 3egati1e G- $a/ .e res#lted and ship heel ./ the angle o! loll
i1% G o! ship sho#ld .e lower
1% Slak tanks sho#ld .e topped #p% 6ill #p s$all tank !irst% 6ill #p low side tank
!irst%
L% (hange o! dra!t !orward and a!t
i% (al#late the .odil/ sinkage 9 rise ( 4 w 9 'P()
ii% (al#late the hange o! tri$ ( 4 tri$ $o$ent 9 -('()
iii% (hange o! dra!t a!t d#e tri$ 4 A(length a!t to 6) 9 (length o! ship)B M (hange o!
tri$)
i1% 6inal dra!t 4 Dld dra!t C .odil/ sinkage C hange d#e tri$
Past N#estionsF
1OO0
1% 5 1essel o! 1>000 tonnes displae$ent has a KG o! L%G$% She plans to work the !ollowing
argoF
load >00 tonnes at Kg 5%L$
load 1>00 tonnes at Kg G%P$
load K50 tonnes at Kg 0%5$
load G010 tonnes at Kg P%>$
disharge >50 tonnes !ro$ Kg L%>$
disharge 1>50 tonnes !ro$ Kg 5%0$
disharge G00 tonnes !ro$ Kg 10%>$
trans!er >000 tonnes !ro$ Kg 1%>$ to Kg 10%>$%
(al#late her !inal G-% K- is onstant at P%>$%
Weight Kg -o$ent
1>,000 L%G PP,P00
>00 5%L 1,1G0
1,>00 G%P 5,LK0
K50 0%5 3>5
G,010 P%> 3>,PP>
;>50 L%> ;1,P00
;1,>50 5%0 ;K,>50
;G00 10%> ;G,0P0
;>,000 1%> ;>,G00
>,000 10%> >0,G00
1K,1K0 13G,LLL
6inal Kg 4 'otal $o$ent9 'otal weight 4 13G,LLL91K,1K0 4 P%3G$
6inal G- 4 K- 6inal KG 4 P%>;P%3G 4 0%1G$
>% 5 1essel o! P000 tonnes displae$ent is to disharge a K0 tonne weight !ro$ the entre
line o! her lower hold (Kg 1%5$) #sing her own derrik%
Gi1en that the height o! the derrik head is 30 $etres a.o1e the keel and that KG is L%5$
and K- P%0$,
(al#lateF
(i) the ships KG when the weight is in s#spension in the lower hold
(ii) the ships KG when the weight is at dek le1el
(iii) the list when the weight has .een sw#ng o#t 1>%0$ !ro$ the entre line%
(i)
Weight Kg -o$ent
P,000 L%5 K0,000
;K0 1%5 ;O0
K0 30 1,P00
P,000 K1,L10
6inal KG 4 -o$ent9 Weight 4 K1,L109 P,000 4 L%L1$
(ii) KG #nhanged (i%e% L%L1$)
(iii) 6inal G- 4 K- 6inal KG 4 P%0 L%L1 4 0%>O$
GG1 4 7ist $o$ent 9 'otal weight 4 K021>9P,000 4 0%0O$
'an (angle o! list) 4 GG19 6inal G- 4 0%0O90%>O
5ngle o! list 4 1L%5 deg
3% 5 1essel is !loating in dok water o! relati1e densit/ 1%0>$ with the #pper edge o! her
s#$$er loadline s#.$erged ./ 10$$%
Gi1en that her 'P(415 and 6W54150$$, al#late how $#h argo to load to reah her
s#$$er displae$ent%
+W596W5 4 (1%0>5;1%0>0)9(1%0>5;1%000)
+W54 0%00521590%0>5 4 30$$
5t this $o$ent the s#$$er loadline is s#.$erged ./ 10$$
'here!ore the ship $a/ !#rther s#.$erged ./ >0$$ or >$
5dditional argo allowed to .e loaded 4 >$ 2 'P( 2 AQ(+W)9 Q(SW)B
4 > 2 15 2 A1%0>9 1%0>5B 4 >O%P5t
1OO1
1% -%8% Sin.ad is !loating #pright in dok water o! :+ 4 1%0>% 'he lower edge o! her
s#$$er load line is 10$$ a.o1e the water%
(al#late how $#h $ore argo she an load to reah her s#$$er displae$ent%
Present dra!t 4 s#$$er dra!t ; $ark width ;10$$4 P%PLO ; 0%0>5 ; 0%01 4 P%PGG$
6ro$ ta.le, displae$ent at seawater at dra!t P%PGG$ 4 >0,000%Gt
+isplae$ent at +W 1%0> at dra!t P%PGG$ 4 >0,000%G 2 1%0>0 9 1%0>5 4 1O,O0>%Pt
5t s#$$er dra!t P%PLO$ +isplae$ent4>0,0OGt
-a2i$#$ argo to load4 >0,0OG 1O,O0>%P 4 1O1%>t
1OO1, 1OO5
K% )2plain, with the aid o! skethes what happens when a ship has #nsta.le e=#ili.ri#$%
N%K (see Ship Sta.ilit/ !or -asters and -ates, 6irth )dition, + : +errett, P%GK)
1OO>, 1OOG
L% )2plain, with the aid o! skethes, wh/ a ship with positi1e sta.ilit/ ret#rns to the #pright
position a!ter .eing inlined ./ an e2ternal !ore%
(see Ship Sta.ilit/ !or -asters and -ates, 6irth )dition, + : +errett, P%GG;G5)
3oteF Positi1e Sta.ilit/ 4 sta.le e=#ili.ri#$)
See notes a.o1e
1OO1
L% 5 1essel o! 1K,000 tonnes displae$ent has a KG o! L%P$% She disharges 3,000 tonnes o!
argo Kg G%L and >%0$ !ro$ the entre line%
(al#late the res#ltant list% K- is onstant at O%5$%
Weight KG -o$ent
1K,000 L%P 1>G,P00
;3000 G%L 1G,100
13,000 110,L00
6inal KG 4 110,L009 13,000 4 P%515$
6inal G- 4 K- 6inal KG 4 O%5 P%515 4 0%OP5$
'rans1erse shi!t o! KG (GG1) 4 7ist $o$ent9 +isplae$ent 4 3,000 2 > 9 13,000 40%GK15$
'an (angle o! list) 4 GG1 9 6inal G-
5ngle o! list 4 >5%1deg
1OO>
1% "sing the G@;#r1e !or di!!erent KG 1al#es at a displae$ent o! 1O0LP tonnes !or -%8%
Sin.ad, !ind !or a KG 4 L%15$,
(i) the initial G-
(ii) G@ at an angle o! heel o! 30R
(iii) the $a2i$#$ G@ and the angle at whih it o#rs
(i1) the range o! positi1e sta.ilit/
State the prea#tions to .e o.ser1ed when #sing a $arine h/dro$eter to asertain the
densit/ o! dok water%
(i) +isplae$ent 4 1O,0OLt K-4O%15
<nitial G- 4 K- KG 4 O%15;L%15 4 >%0$
(ii) G@ at angle or list 30deg 4 1%>5$
(iii) -a2% G@ 4 1%G$ at angle o! list G>%5deg
(i1) :ange o! sta.ilit/ 4 O0deg
,. 5 1essel o! 15,000 tonnes displae$ent and 1O0$ length, disharges G00 tonnes o! argo
!ro$ 30$ !orward o! a$idships%
"sing the !ollowing parti#lars al#late her !inal dra#ghts !orward and a!t%
Driginal dra#ghts P%0$ !orward, L%P$ a!t
7(6 is a$idships 'P( 4 >5 -('( 4 >00 tonnes $%
Bodil/ rising 4 Weight disharged9 'P( 4 G009>54 0%1K$
(hange o! tri$ 4 tri$$ing $o$ent9 -('( 4 G002309 >00 4 K0$ 4 0%K$
(hange o! a!t dra!t 4 7(6 2 hange o! tri$9 7D6 4 1 2 0%K 9 > 4 0%3$
(hange o! !orward dra!t 4 hange o! tri$ hange o! a!t tri$ 4 0%K;0%3 4 0%3$
6orward 5!t
<nitial dra!t P%0 L%P
Bodil/ :ising ;0%1K ;0%1K
(hange o! dra!t ;0%3 0%3
6inal dra!t L%5G L%OG
1OO3
1% (a) "sing the in!or$ation gi1en !or -%8% Sin.ad, al#late, at her s#$$er load
dra#ght,
1)1ol#$e o! displae$ent
>)area o! the load waterplane
3)area o! $idship setion
G)light ship displae$ent
5)6%W%5%
K)+W5 at :+ F 1%010
(.) State the prea#tions to .e o.ser1ed when #sing a $arine h/dro$eter to asertain the
densit/ o! dok water%
N% 51 (a)
i% 5t s#$$er load dra!t P%PLO$ S P%PP$, +isplae$ent 4 >0,0O0t, 8ol#$e 4 +isplae$ent 9
densit/ 4 >0,0O0 9 1%0>5 4 1O,K00t
ii% Waterplane area 4 7 2 B 2 water plane o;e!!iient 4 1G0 2 >>%5O 2 0%P51 4 >PLG%OK
#.%$etre
iii% -idship area 4 B 2 s#$$er dra!t 2 -idship setion (o;e!!iient 4 >>%5O 2 P%PLO 2 0%O3P
4 1PP%1G #.%$etre
i1% 7ight ship +isplae$ent 4 di!!erene o! displae$ent and deadweight at an/ dra!t 4
1L,LL0 13,>3P%P 4 G531%>t
1% 6W5 4 +isplae$ent 9 'P( at s#$$er dra!t 9 G 4 >0,0OL 9 >K%5P 9 G 4 1PO$$
1i% +W5 9 6W5 4 (Qsw Qdw) 9 (Qsw Q!w)
+W5 4 (10>5;1010) 2 1PO 9 (10>5;1000)
(.)
)2isting port list $o$ent 4 displae$ent 2 G- 2 tan (angle o! list) 4 10,000 2 0%5 2 tan
3%0deg 4 >K>%0Gt$
:e=#ired star.oard list $o$ent 4 >K>%0G 4 weight 2 distane !ro$ enterline
+istane !ro$ enterline 4 >K>%0G 9 500 4 0%5>G$
K% 5 1essel o! 10,000 tonnes displae$ent has a KG o! P%5$ and a G- o! 0%5$% She has a 3R
port list and still has 500 tonnes o! argo to load in the tween dek, Kg 1>%0$% (al#late
how !ar !ro$ the entre line this argo sho#ld .e loaded to .ring the ship #pright%
:e=#ired righting $o$ent 4 present list $o$ent 4 +isplae$ent 2 G- 2 tan(angle o! list) 4
10,000 2 0%5 2 tan (3%0deg) 4 >K>%0G$t
+istane o! the argo to load !ro$ enterline 4 :ighting $o$ent9 weight 4 >K>%0G9500 4
0%5>$
L% 5 1essel o! 1>000 tonnes displae$ent has a KG o! P%5$% She disharges >000 tonnes o!
sea water .allast, Kg G%>$ and loads the !ollowingF
G00 tonnes o! plasti, Kg 5%0$
3000 tonnes o! !ertiliHer, Kg 3%5$
(al#late her !inal KG%
Weight KG -o$ent
1>,000 P%5 10>,000
;>000 G%> P,G00
G00 5%0 >,000
3,000 3%5 10,500
13,G00 10K,100
6inal KG 4 10K,1009 13,G00 4 L%O1P$
1OOG
51% -%8% Sin.ad is sails with an e1en keel dra#ght o! P%50$ and a KG o! L%5$%
'he !ollowing tanks are OK% !#ll,
T3 6%D%'% (), Kg 1%1$
TG 6%D%'% (), Kg 1%1$
TL 6%D%'% (p U s), Kg 1%P$
5!ter arri1al at the disharging port the a.o1e tanks are e$pt/ and 1050 tonnes o! argo, Kg
K%>$, ha1e .een disharged%
(al#late the !inal G-% :%+% 10>5%
N% 51
+ra!t P%5$ +isplae$ent 4 1O,0LPt , K- 4 O%15$,
Weight KG -o$ent
1O,0LP L%5 1G3,0P5
;>OG%GO 1%1 ;3>3%O3O
;>K0%L> 1%1 ;>PK%LO>
;100%G1 1%P ;1P0%L3P
;135%PO 1%P ;>GG%K0>
;1050 K%> ;K510%00
1L>3K%GO 135,53P%O>O
6inal KG 4 135,53P%O>O 9 1L>3K%GO 4 L%PK3$
+isplae$ent 1L,>3K%GO, 3ew K- is #no.taina.le in the ta.le VVV
G- 4 3ew K- 3ew KG 4 VVV L%PK3 4 VVV
BG% 5 1essel o! 1>000 tonnes displae$ent has a KG o! P%5$% She disharges >000 tonnes o!
sea water .allast, Kg G%> and loads the !ollowing argoF
G00 tonnes o! plasti, Kg 5%0$
3000 tonnes o! !ertiliHer, Kg 3%5$%
(al#late her !inal KG%
Weight KG -o$ent
1>,000 P%5 10>,000
;>,000 G%> ;P,G00
G00 5%0 >,000
3000 3%5 10,500
13,G00 10K,100
6inal KG 4 10K,100 9 13,G00 4 L%O>$
51% -%8% Sin.ad is !loating #pright and at an e1en keel dra#ght o! P%15$ in seawater% KG 4
L%>0$% 5 piee o! $ahiner/ weighing 3G0 tonnes, Kg 4 1>%5$ and sit#ated K%0$ o!! the
enterline to port, is disharged ./ shore rane%
(al#late the res#ltant list%
N% 51
7ist $o$ent d#e to argo disharged 4 3G0t 2 K$ 4 >0G0t$ (to star.oard)
5t dra!t P%15$ displae$ent 4 1P,15Pt,
3ew displae$ent 4 1P,15Pt 3G0t 4 1L,P1Pt new K- 4 O%0L$
GG1 4 7ist $o$ent9 displae$ent 4 >0G09 1LP1P 4 0%11G5$
Weight KG -o$ent
1P,15P L%> 130,L3L%K
;3G0 1>%5 ;G,>50
1L,P1P 1>K,GPL%K
6inal KG 4 1>K,GPL%K9 1L,P1P 4 L%0OO$
6inal G- 4 3ew K- 6inal KG 4 O%0L L%0OO 4 1%OL$
'an (angle o! list) 4 GG19 G- 4 0%11G59 1%OL
5ngle o! list 4 3%3 deg to star.oard
BK% 5 1essel o! 1K>00 tonnes displae$ent has a KG o! P%L0$% 5 do#.le .otto$ tank, >0$ 2
>5$ 2 1$, is !#ll o! !resh water%
(al#late the !inal G- i! hal! o! this !resh water is ons#$ed% 5ss#$e the e!!et o! !ree
s#r!ae is to red#e the G- ./ 0%P3$% K- is onstant at 10%3$%
'otal !resh water weight 4 7 2 B 2 + 2 Q 4 >0 2 >5 2 1 2 1%000 4 500t
Driginal KG o! the +B tank 4 1%0 9 > 4 0%5$
6inal KG o! the +B tank 4 0%5 9 > 4 0%>5$
Weight KG -o$ent
1K>00 P%L 1G0,OG0
;500 0%5 ;>50
>50 0%>5 K>%5
1K,150 1G0,L5>%5
6inal KG 4 1G0,L5>%59 1K,150 4 P%P>$
G- (solid) 4 K- KG 4 10%3 P%P> 4 1%GP$
G- (!l#id) 4 G- (solid) 6ree s#r!ae e!!et orretion 4 1%GP 0%P3 4 0%K5$
5>% (a) -%8% I-)W35 <<<J is !loating in salt water and displaes 1K, 0PK tonnes%
She has a positi1e G- o! 0%5G $etre%
Plot a #r1e o! G@ le1ers o! the ship (statial sta.ilit/ #r1e)%
(.) Brie!l/ e2plain the in!or$ation whih an .e o.tained !ro$ the #r1e%
N% 5>(.)
-a2% G@ 4 0%P55$ at angle 3P deg
G- 4 0%5G$
5ngle o! 1anishing sta.ilit/ 4 KO deg
:ange o! sta.ilit/ 4 0 deg S KO deg
B3% (a) )2plain wh/ slak tank in a ship red#e the e!!eti1e G- o! that ship%
(.) <n -%8% I-)W35 <<<J, the argo oil tanks in n#$.er G hold ontain 1egeta.le oil with
a spei!i gra1it/ o! 0%P%
5ll !o#r tanks are #naepta.l/ slak%
<! her G-
solid
was 0%5 $etre, what is her G-
!l#id
V
N% B3 (a) 5s the ship roll, the $o1e$ent o! the water inside the tank 1irt#all/ inrease the
entre o! gra1it/ o! the li=#id and th#s the entre o! gra1it/ o! the ship% G-4K-;KG% <! KG
inreases, e!!eti1e G- derease%
(.) 'otal 6S- 4 (G05CG05C3>LC3>L) 2 0%P 4 1,1L1%>$t
8irt#al loss o! G- 4 6S-9 +isplae$ent
+isplae$ent 4 VVVVVVVVVVVV
(5nswer #nknownVVVVVVVVVVVVVVV)
BG% (a) )2plain wh/ a ship $a/ lie at an Iangle o! lollJ%
(.) Sketh and desri.e a t/pial #r1e o! statial sta.ilit/ !or a 1essel with an angle o!
loll%
N% BG(a) 5n angle o! loll o#rs when G- is negati1e% 3egati1e G- $a/ .e a#sed ./
i$proper wa/ o! loading 9 disharging% 5t sea, d#e to the ons#$ption o! !#el, it $a/ .e the
ase that a 1essel whih le!t port with positi1e G-, has now de1eloped a negati1e G-%
(.) (see Ship Sta.ilit/ !or -asters and -ates, 6irth )dition, + : +errett, P%GP)
see notes a.o1e
51% 5 1essel o! P000 tonnes displae$ent is to disharge a K0 tonnes weight !ro$ the
enterline o! her lower hold, Kg 1%5$, #sing her own derrik%
Gi1en that the height o! the derrik head is 30 $etres a.o1e the keel and that KG is L%5$
and K- P%0$,
(al#lateF
(i) 'he ship0s KG when the weight is in s#spension in the lower hold,
(ii) 'he list when the weight has .een sw#ng o#t 1>%0$ !ro$ the enterline%
N% 51 (i)
Weight Kg -o$ent
P000 L%5 K0000
;K0 1%5 ;O0
K0 30 1P00
P000 K1L10
6inal Kg 4 'otal -o$ent9 'otal Weight
K1L109 P000
L%L1G$
N%51 (ii)
G- 4 K- KG 4 P%0 L%L1G 4 0%>PK$
GG1 4 7ist -o$ent 9 'otal Weight 4 L>0 9 P000 4 0%0O$
tan (angle o! list) 4 GG1 9 G- 4 0%0O90%>PK$
angle o! list 4 1L%5 deg
B>% 5 1essel is tri$$ed 35$ ./ the stern% She loads >00 tons o! argo 100$ !orward o! the
a!ter perpendi#lar and disharges >00 tonnes O0$ !orward o! the a!ter perpendi#lar%
Gi1en that her entre o! !loatation is P0$ !orward o! the a!ter perpendi#lar and her
-('( is >50 tonnes $etres, al#late her !inal tri$%
Weight +istane 'ri$$ing -o$ent
>00 >0 G000$t ./ head
>00 10 >000$t ./ stern
G00 >000$t ./ head
(hange o! tri$ 4 tri$$ing $o$ent 9 -('( 4 >0009>50 4 P$ ./ head
6inal tri$ 4 present tri$ C9; hange o! tri$ 4 35$ P$ 4 >L$ ./ stern
BG% 5 1essel o! 5000 tonnes displae$ent has a KG o! K%0$% She then works the !ollowing
argoF
300 tonnes loaded at Kg L%0$,
>00 tonnes loaded at Kg >%0$,
500 tonnes disharged !ro$ Kg 5%0$%
G00 tonnes o! dek argo, Kg P%3L$ is then trans!erred to a lower hold, Kg 1%3L$%
(al#late her !inal KG%
Weight Kg -o$ent
5000 K%0 30000
300 L%0 >100
>00 >%0 G00
500 5%0 ;>500
G00 P%3L ;33GP
G00 1%3L 5GP
5000 >L>00
6inal Kg 4 'otal -o$ent9 weight 4 >L>00$t9 5000t 4 5%GG$