DieselShip's Online Content Library

Q7. A. Describe stability requirement for dry-docking. B. A ship of 8000 tonne displacement, 110m long, floats in sea water of 1.024t/m3 at draughts of 6m forward and 6.3 m aft. The TPC is 16, LCB 0.6 m aft of midships, LCF 3m aft of midships and MCT1cm 65 tonne m, the vessel now moves into fresh water of 1.000t/m3. Calculate the distance a mass of 50 tonne must be moved to bring the vessel to an even keel and determine the final draught.

Q8. A box shaped vessel is 80 m long, 12 m wide and floats at a draught of 4m.

A full width midships compartment 15 m long is bilged and this results in the draught increasing to 4.5 m. Calculate EACH of the following,

(a) The permeability of the compartment;

(b) The change in metacentric height due to bilging.

Q4. A ship of displacement 11000 tonne has a length 120 m, breadth 16 m, and even keel draught of 5.5 m in sea water of density 1025 kg/m3. The area of the waterplane is 1440 m2 and the second moment of area of the waterplane about a transverse axis through midships is 1.2 × 106 m4 with the LCF at midships. The ship has a full depth empty rectangular compartment of length 12 m and breadth 10 m.  The center of the compartment is on the centerline of the ship 40 m forward of midships.

Calculate the end draughts after the compartment is bilged.

Q6. A. Explain how wave profile affects the shear force and bending moment curves. B. A ship 125m long displaces 12000 tonne. When a mass of 100 tonnes is moved 75m from forward to aft there is a change in trim of 65 cm by the stem. Calculate - MCTI cm; The longitudinal metacentric height; The distance moved by the centre of gravity of the ship.

Q10: A. Explain the term volumetric heeling moments. B. A box barge 33m long and 5.5m wide has a light displacement and KG of 216 tonne and 2.75 m respectively. 80 tonne of machinery are put on board and in order to maintain stability 54 tonne of Ballast are at Kg 0.15m.  The final GM is 0.13 m. Calculate the Kg of the added machinery.

Q7. A) Why is an inclining experiment carried out? Write short account of the method adopted.

b) An inclining experiment was carried out on a ship of 8000 tonne displacement. The inclining ballast was moved transversely through 12 m and the deflections of a pendulum 5.5m long, measured from the centreline, were as follows

3 tonne port to starboard 64 mm S

3 Tonne 116 mm S

Ballast restored 3 mm S

3 Tonne starboard to port 54 mm P

3 tonne starboard to port 113 mm P

Calculate the metacentric height of the vessel. (10)

Q8. A. Explain the purpose of non-watertight longitudinal subdivision of tanks. (6)

B. A ship 160m long and 8700 tonne displacement floats at a waterline with ½ ordinates of 0, 2.4, 5.0, 7.3, 7.9, 8.0, 8.0, 7.7, 5.5, 2.8, 0m respectively. While floating at this waterline, the ship develops a list of 10° due to instability. Calculate the negative metacentric height when the vessel is upright in this condition. (10)

Q7. a) Describe briefly the significance of the factor of subdivision. (6)

b) A ship 120m long has a light displacement of 4000 tonne and LCG in this condition 2.5m aft of midships.  (10)

The following items are then added:

Cargo 10000 tonne      LCG 3.0 m  forward of midships

Fuel 1500 tonne        LCG 2.0 m  aft of midships

Water         400 tonne  LCG 8.0 m  aft of midships

Stores        100 tonne LCG 10.0m forward of midships

Using the following hydrostatic data, calculate the final draughts:

Q10. A box-shaped vessel is 20 m long and 10 m wide.  The weight of the vessel is uniformly distributed throughout the length and the draught is 2.5 m.  The vessel contains ten evenly spaced double bottom tanks, each having a depth of 1m. Draw the shear force diagrams:

With No.1 and No.10 tanks filled; With No.3 and No.8 tanks filled; With No.5 and No.6 tanks filled.

Which ballast condition is to be preferred from the point of view of strength?

Q7. (a) Describe how bulkheads are tested.

B. The following data are available for a twin-screw vessel:

V (Knots)
15
16
17
18
Epn (KW)
3000
3750
4700
5650
QPC
0.73
0.73
0.72
0.71
Calculate the service speed if the breaker power for each engine is 3500Kw. The transmission is 3% and the allowances for weather and appendages 30%.

Q6. a) Derive the expression for current and voltage relations between line and phase values in the star and delta cases. Draw vector diagram. (6)

b) A balanced delta connected load is connected to a 415V, 50 Hz Supply. If the per phase impedance of the load is (8+j12) ohm, calculate (i) the phase current of the load. (ii) line current (iii) power consumed by each phase. (10)

Q9. a) Explain the term Angle of loll and state the dangers it poses to a vessel. What action to be taken to correct angle of loll. (6)

B. A forward deep tank 12 m long extends from a longitudinal bulkhead to the ship’s side. The widths of the tank surface measured from the longitudinal bulkhead at regular intervals are 10, 9, 7, 4 and 1 m. Calculate the second moment of area of the tank surface about a longitudinal axis passing through its centroid. (10)