Q1. A ship 126 m floats at a draught of 7.5 m and in this condition the immersed cross sectional areas and waterplane areas are as given in Tables Q1(A) and Q1(B). The equivalent base area (Ab) is required because of the fineness of the bottom shell.
(a) the equivalent base area value Ab; (8)
(b) the longitudinal position of the centre of buoyancy from midships; (4)
(c) the vertical position of the centre Of buoyancy above the base. (4)
Q3. The following particulars apply to a ship of length 140 m when floating in sea water of density 1025 kg/m3 at an even keel draught of 7.265 m. displacement = 15800 tonne centre of gravity above the keel (KG) = 7.8 m centre of buoyancy above the keel (KB) = 4.05 m waterplane area = 2146 m2 centre of flotation from midships (LCF) = 3.0 m aft second moment of area of the waterplane about a transverse axis through midships = 2.305 × 106 m4 (a) Calculate the value of the moment to change trim by one centimetre (MCT1cm) in the above condition. (6) (b) The ship in the above condition now undergoes the following changes in loading: 352 tonne added at an Lcg of 10.5 m forward of midships 110 tonne removed from an Lcg of 2.0 m aft of midships 150 tonne restowed at a new position 52.7 m aft of its original position. Calculate the new end draughts of the ship. (10)
Q5. A box barge of length 50 m is of uniform construction and has a displacement of 600 tonne when empty.
The barge is divided by four transverse bulkheads to form five holds of equal length. Cargo is loaded as shown in Fig Q5, the cargo in each hold being uniformly distributed.
For this condition of loading:
(a) verify that the barge has an even keel draught; (2)
(b) draw to scale EACH Of the following:
(i) the load diagram; (6)
(ii) the shear force diagram; (5)
(c)using the diagrams drawn in Q5(b), determine the longitudinal position of the maximum bending moment. (3)
Q11. A ship of length 160 m and breadth 28 m floats at a draught of 12 m in sea waler of density 1025 kg/m2 with a block coefficient of 0.7.
Allowance for appendages = 6%
Allowance for weather = 14%
Quas-propulsive coefficient (QPC) = 0.71
A geometrically similar model 8 m in length, when tested at a speed of 1.6 m/s in fresh water of density 1000 kg/m3 gives a total resistance of 82 N. Calculate the service delivered power for the ship at the corresponding speed to that of the model;
Note: The frictional coefficient for the model in fresh water is 1.69
The frictional coefficient for the ship in sea water is 1.42
Speed is in m/s with index (n) = 1.825
Wetted surface area (m) = 2.6 √A X L
Q8. A vessel of 10500 tonne displacement is fitted with a propeller Of 5.5 m diameter
and pitch ratio 0.9.
During a fuel consumption trial of 6 hours duration, a steady shaft speed of 1.8 revs/sec was maintained and 7.54 tonne of fuel was consumed.
The following results were also recorded:
real Slip ratio = 0.34
Taylor wake fraction = 0.32
shaft power = 6050 kW
transmission losses = 3%
quasi-propulsive coefficient (QPC) = 0.71
propeller thrust = 680 kN
Calculate EACH of the following:
(a) the speed of the ship; (4)
(b) the apparent Slip ratio; (1)
(c) the propeller efficiency; (3)
(d) the thrust deduction fraction; (3)
(e) the fuel coefficient; (3)
(f) the specific fuel consumption. (2)
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