Question

With respect to Buoyancy of a vessel:

(a) What do you understand by reserve buoyancy what happen if the lost buoyancy is greater than the reserve buoyancy. (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 seeond moment of area of the tank surface about a longitudinal axis passing through its centroid. (10)

Answer 1

Part (a)

Reserve Buoyancy

Reserve buoyancy is the watertight volume above the waterline of a vessel. It represents the potential buoyancy that can be utilised to keep the ship afloat when additional weight is added or if some buoyancy is lost due to damage (e.g., bilging).

When a mass is added to the ship or buoyancy is lost (e.g., due to flooding of a compartment), the reserve buoyancy is converted into active buoyancy by an increase in draught.

If the lost buoyancy (due to flooding or damage) is greater than the reserve buoyancy, the vessel will no longer have sufficient buoyant force to counteract its weight, causing it to sink.

Part (b)

✓ Verified Model Answer (Text Solution)

Reserve Buoyancy