Stability – I : Chapter 7 |

# Stability – I : Chapter 7

###### VM
300t (load) 2.0m (+) 600 tm
200t   (load) 3.2m (+) 640 tm
500t  (load ) 1.0 m (+)500 tm

Final W   = 300t                                                           Final VM = 10140 tm

We know that:-

Final KG =   (Final VM) / (Final W)
Final KG    = 10140 / 3000
= 3.38m

###### Solution:
 Ship’s weight KG VM 3000 t 3.9m 11700tm 200t (load) 3.0m (+) 600tm 300t 6.4m (+) 1920tm 150t 5.2m (+) 780tm 350t 4m (+)1400tm

Final W   = 4000 t                                                       Final VM = 16400 tm

We know that:-

Final KG =   (Final VM) / (Final W)
Final KG = (16400/4000)
= 4.1m

###### Solution :
 Ship’s weight KG VM 10000t 6.0m 60000 tm (-) 250t (discharge) 3.0m (-) 750 tm (-) 150t (discharge) 4.0m (-) 600 tm

Final  W  =  9600t                                                 Final  VM = 58650 tm

We know that:-

Final KG =   (Final VM) / (Final W)
Final  KG  = (58650 / 9600)
= 6.109m.

###### VM
2000t 3.66m 7320tm
2000t ( discharge) 2.44m (-) 4880tm
900t  (discharge) 0.40m (-)360tm

Final W   =   5620t                                                    Final VM  = 27342tm

We know that:-

Final KG =   (Final VM) / (Final W)
Final KG = (27342) / (5620)
= 4.865m

###### VM
3200t 6.2m 19840tm
(+) 5200t (load) 4.8m (+)24960 tm
(+) X t 10m (+) 10X tm

Final W  = (8400 + X )t                                     Final VM   =(44800 +10X);

We know that:-

Final KG =   (Final VM) / (Final W)
6 = (44800 + 10X )/( 8400 + X)
6 (8400 + X  )  = ( 44800 +10X)
(50400 + 6X ) = (10X + 44800)
( 10X – 6X) = (50400 – 44800)
4X = 5600
X  =  1400t

Hence , amount of deck cargo to be loaded to get  required KG is  1400 t

###### VM
2600t 4.88m 12688 tm
X t (load) 10m 10X tm

Final W   = (7200 + X) t                                              Final VM =(35688 + 10X) tm

We know that:-

Final KG =   (Final VM) / (Final W)
5.11  =  (35688 + 10X )/( 7200 + X )
5.11( 7200 + X) = (35688 + 10X)
(36792  + 5.11X )  = (35688 +10X)
(36792 – 35688) = (10X – 5.11X )
X  =  1104 / 4.89
X  =225.766t.

Hence amount of deck cargo added to get desired KG is 225.76 t.

1. A heavy-lift derrick is used to discharge a 100t package from a ship of displacement 8000t kg 8.2m . If the KG  of the weight while on board is 3m and if the derrick head is 25m above the keel , find the kg of the ship  (a) while discharging and( b ) after discharging

Solution :

CASE 1

###### VM
8000t 8.2m 65600tm
100t ( while disch) (25 -3m) (+)2200tm

Final W  = 8000t                                                                 Final VM  =  67800t

We know that:-

Final KG =   (Final VM) / (Final W)
Final  KG   =  ( 67800/8000)
=  8.475m

Case – 2

###### VM
8000t 8.2m 65600tm
(-)100t 3m (-)300tm

Final W  = 7900t                                                                Final VM = 65300tm

We know that:-

Final KG =   (Final VM) / (Final W)
Final KG   = (65300/7900)
= 8.266m

Case – 1

###### VM
15000t 7.9m 118500tm

Final W  =  15200T                                                           Final  VM  = 124500tm

We know that:-

Final KG =   (Final VM) / (Final W)
Final KG = (124500/15200)
= 8.190m

Case – 2

###### VM
15000t 7.9m 118500tm

Final W   =  15200                                                               Final VM = 120900 tm

We know that:-

Final KG =   (Final VM) / (Final W)
Final KG   =   (120900/15200)
=7.954m.

Case -1

###### VM
11000t 7.2m 79200tm
(-)180t (while shifting) 12m (-)2160tm

Final W =  10820t                                                            Final VM = 77040 tm

We know that:-

Final KG =   (Final VM) / (Final W)
Final KG   = 77040 / 10820
= 7.120m

Case – 2

###### VM
11000t 7.2m 79200tm
180t (After shift) (12-3)m (-)1620tm

Final  W = 11000                                                        Final VM =   77580tm

We know that:-

Final KG =   (Final VM) / (Final W)
Final KG = (77580/11000)
= 7.053m. 