A ship 150m 20m floats on an even keel at 10m draft and has a block coefficient of fineness 0.8 and LGM of 200 metres. If 250 tonnes of cargo is discharged from a position 32m from the centre of flotation, find the resulting change of trim.

A ship 150m 20m floats on an even keel at 10m draft and has a block coefficient of fineness 0.8 and LGM of 200 metres. If 250 tonnes of cargo is discharged from a position 32m from the centre of flotation, find the resulting change of trim.

Reference: Ship Stability for Masters & Mates (6^th edition), Exercise – 16.7

 

Solution:

C_b = ∇ /L*B*d

=> 0.8 = ∇/150*20*10

=> ∇ = 24000 m³

 

MCTC = W*BM_L/100L

            = 24000*1.025*200/100*150

            = 328 ton-m/cm

 

Change in trim = w*d/MCTC

                         = 250*32/328

                         = 24.4 cm

                         = 0.24 m