Q1. At a draught of 1.0 m in sea water of density 1025 kg/m3 the displacement of a ship is 900 tonne and the height of the centre of buoyancy above the keel (KB) is 0.6 m.
Values of tonne per centimetre immersion (TPC) in sea water for a range of draughts
are given in Table Q1.
(a) Calculate EACH of the following for a draught of 6.0 m in sea water:
(i) the displacement; (4)
(ii) the height of the centre of buoyancy above the keel (KB). (6)
(b) At a draught of 6.0 m, the height of the longitudinal metacentre above the keel (KML) is 128 m and the second moment of area of the waterplane about a transverse axis through midships is 996728 m4.
The centre of flotation is aft of midships.
Calculate the distance of the centre of flotation (LCF) from midships. (6)
Q2) A ship of 10000 tonne displacement floats in sea water of density 1025 kg/m3 at a draught of 6 m.
A rectangluar tank 10 m long and 8 m wide is partially full of oil fuel having a density of 900 kg/m3.
In this condition, the KG of the ship is 6.25 m.
Other hydrostatic data for the above condition are:
Centre of buoyancy above the keel (KB) = 3.325 m
Transverse metacentre above the centre of buoyancy (BM) = 4.865 m
Tonnes per centimetre immersion (TPC) = 20.5
Calculate the change in effective metacentric height when a rectangular tank 12 m long 10 m wide and 6 m deep, with its base 1 m above the keel, is filled to depth of 5 m with sea water ballast. (16)
Note : Assume the ship to be wall-sided over the affected range of draught
Q4. For a box shaped barge 100 m in length, 15 m breadth, floating at an even keel draught of 8 m in sea water Of density 1025 kg/m3, the KG is 5 m.
A full breadth midship compartment 10 m long is divided by a centretine watertight longitudinal bulkhead to form two equal compartments. One of the compartments is bilged. The permeability of the flooded compartment is 85% . Calculate the angle of heel for the barge. (16)
Q3. A ship of length 130 m is loaded as shown in Table Q3(a).
Table Q3(a)
The following hydrostatic data in Table Q3(b) can be assumed to have a linear relationship between the draughts shown.
Table Q3(b)
Calculate the final end draughts. (16)
Q6) The force acting normal to the centreline plane of a rudder is given by the expression:
Fn =15.5 A V2 α newtons
Where: A = rudder area (m2)
V = ship speed (m/s)
α = rudder helm angle(degrees)
A ship travelling at a speed of 20 knots, has a rudder configuration as shown in Fig Q6.
The centre of effort for areas A1 and A2 are 32% of the width from their respective leading edges. The rudder angle is limited to 35ofrom the ship’s centreline.
Fig Q6
Calculate EACH of the following:
(a) the diameter of rudder stock required for a maximum allowable stress of 77MN/m2; (12)
(b) the drag component of rudder force when the rudder is put hard over at full speed. (4)
Q7) A ship consumes an average of 70 tonne of fuel per day on main engines at a speed of 17 knots. The fuel consumption for auxiliary purposes is 8 tonne per day.
When 800 nautical miles from port it is found that 140 tonne of fuel remains on board and this will be insufficient to reach port at the normal speed.
Using a graphical solution, determine the speed at which the ship should travel to complete the voyage with 20 tonne of fuel remaining. (16)
Username or email address *Required
Password *Required
Note: Entering wrong username in the login form will ban your IP address immediately. Entering wrong password multiple times will also ban your IP address temporarily.
Log in
Lost your password? Remember me
No account yet?
