Question

(a) Explain what is meant by floodable length. (6)

(b) (i) Construct a graph from the following information:

Mean draft (m)	3.0	3.5	4.0	4.5
TPC (tonnes)	8.0	8.5	9.2	10.0

(ii) From this graph find the TPC's at draft of 3.2m, 3.7m, and 4.3m.

(iii) If the ship is floating at a mean draft of 4m, and then loads 50 tonnes of cargo, 10 tonnes of fresh water, and 25 tonnes of bunkers, whilst 45 tonnes of ballast are discharged, find the final mean draft. (10)

Answer 1

Part (a)

Floodable length

is the amount, the ship can be flooded without the risk of sinking. i.e. the maximum length of the ship that can be flooded without submerging the margin line. The margin line is located 75mm below the bulkhead deck, providing a safety margin.

A floodable length curve can be drawn for different permeability.
It is used to test the after-bulkhead length so that the bulkhead length is sufficient to contain the flooding without sinking the vessel.
Factor of subdivision = Permissible length / Floodable length

✓ Verified Model Answer (Text Solution)

Floodable length