Q1. A ship floats at a draught of 10 m In sea water of density 1025 kg/m3.
In this condition the centre of gravity is 9.896 m above the keel and the second moment of area of the waterplane about the centreline Is 94030 m4.
Values of tonne per centimetre Immersion (TPC) in sea water are given in
A load is to be discharged from the ship's centreline by the ship's own heavy lift crane. The Crane head is 12 m above the original centre of gravity of the load and 16 m from the centreline of the ship when swung out. During the discharge it is required that the metacentric height of the ship should not be less than 1.75 m. Calculate EACH Of the following:
(a) the maximum load the crane may lift; (14)
(b) the angle to which the ship will heel when discharging the maximum load. (2)
Q5. a) Sketch and label a statical stability curve for a vessel with its center of gravity on the centerline but having a negative metacentric height when in the upright condition.
(b) The ordinates for part of a statical stability curve for a bulk carrier at a displacement of 18000 tonne are given in Table Q2.
The ship has a hold 40 m long and 30 m wide which contains bulk grain stowed at a stowage rate of 1.25 m3/tonne.
During a heavy roll, the grain shifts so that the level surface is lowered by 1.5 m on one side and raised by 1.5 m on the other side.
(i) Draw the amended statical stability curve for the ship.
(ii) From the curve, determine the angle of list due to the cargo shift.
Q6. A ship 120 m long floats at draughts of 6.6 m aft and 4.2 m forward when floating in river water of density 1008 kg/m³. Using the hydrostatic curves provided in Worksheet Q3, determine EACH of the following:
(a) The displacement;
(b) The longitudinal position of the centre of gravity.
Q1. A box shaped vessel is 80 m long, 10 m wide and floats at an even keel draught of 4 m in water of density 1025 kg/m3 with a KG of 3.43 m. A full width empty compartment at the forward end of the vessel is 10 m long and has a watertight flat 2.5 m above the keel. This end compartment is now bilged above the flat only. Calculate the new end draughts of the vessel.
Note: The KB in the bilged condition may be taken as half the new mean draught.
Q7) A ship of length 156 m and breadth of 24 m floats at a draught of 8.25 m in sea water of density 1025 kg/m3. In this condition the block coefficient (Cb) is 0.72.
A geometrically similar model, 6 m in length, gives a total resistance of 43.55 N when tested at a speed of 1.65 m/s in fresh water of 1000 kg/m3 at a temperature of 12oC.
The following data are also available:
Ship correlation factor = 1.23
Temperature correction = ±0.43% per oC.
Wetted surface area(S) = 2.57 √∆L (m2)
Frictional coefficient for the model in water of density 1000 kg/m3 at 15oC is 1.655
Frictional coefficient for the ship in water of density 1025kg/m3 at 15oC is 1.411
Speed in m/s with index (n) for ship and model 1.825
The ship is travelling at the corresponding speed to the model in sea water of density 1025 kg/m3 at a temperature of 15oC.
Calculate the effective power of the ship. (16)
Q1. The following data apply to a ship travelling at 17 knots:
Propeller speed 1.85 rev/s
Propeller pitch ratio 0.95
Real slip ratio 0.34
Taylor wake fraction 0.30
Torque delivered to the propeller 480 kNm
Propeller thrust 640 kN
Quasi-propulsive coefficient (QPC) 0.71
Transmission losses 3%
Fuel consumption per day 28 tonne
Determine EACH of the following:
(a) The apparent slip ratio;
(b) The propeller diameter;
(c) The propeller efficiency;
(d) The thrust deduction fraction;
(e) SFC
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?
