Page 420 - statbility for masters and mates

408 Ship Stability for Masters and Mates
SHIP STABILITY
Attempt ALL questions
Marks for each question are shown in brackets
1. A box shaped vessel, length 90 m, breadth 13 m, depth 8 m is ¯oating at an even keel draft of 4.0 m. There is a deeptank amidships, length 18 m, breadth 13 m extending from the ship's bottom to a watertight ¯at 4.2 m above the keel.
The deeptank is tightly stowed with cargo of relative density 1.14 and stowage factor 1.5 m3/t.
Calculate the resultant draught if this deeptank is bilged. (35)
2. (a) De®ne dynamical stability. (5) (b) The righting levers of a vessel displacing 9500 t are as follows:
Heel: 0 10 20 30 GZ (m): 0 0.04 0.14 0.40
Calculate EACH of the following:
40 0.55
(i) the dynamical stability at 40 ;
(ii) the residual dynamical stability at 40 if the vessel is subjected to
a steady wind moment of 380 tm. (15)
3. (a) The Loadline Rules require the master to be provided with stability particulars for various conditions. Detail the information to be provided for a given service condition and describe how this information may be presented. (20)
(b) A ship plans to depart from port at:
Displacement 18 000 t KG 8.02 m
During the ensuing voyage the ship will consume 60 t of fresh water (Kg 0.8 m) and 240 t of bunkers (Kg 1.4 m) from full tanks causing a free surface moment of 2100 t m.
Using Datasheet Q.3 `Maximum KG', determine the stability condition of the ship both on departure and on arrival. (15)
4. Describe the Loadline Rules requirements governing the ability of Type B vessels with reduced freeboard to withstand ¯ooding due to damage, and the stability in the ®nal condition. (30)
5. Discuss the stability problems associated with the operation of an oil rig supply vessel. (30)
6. (a) List the precautions to be observed before and during an inclining experiment to ®nd a vessel's KG. (10) (b) State the maximum interval at which the inclining test must be carried out on a Passenger Ro/ro vessel. (5) (c) From the following results of an inclining test, calculate the KG of
the vessel in the Lightship Condition, KM 8.1 m.
(15)