CALCULATING THE FINAL DRAFTS WHEN A WEIGHT IS SHIFTED

Consider the ship where a weight is shifted longitudinally.

It can be seen that the LCF is in the same position in the ship’s length as the point where the initial and final waterlines intersect.

It may be helpful to think of the ship as a child’s see-saw that has its pivot point situated at the LCF.

A) Ship with LCF amidships

Example:

A ship floats at drafts F 6.50 m and A 6.80 m. Determine the final drafts if 25 tonnes is moved 45 m forward given that MCTC is 112.5 t-m and the LCF is amidships.

B) Ship with LCF not amidships

Example:

A ship has initial drafts F 10.25 m and A 10.15 m. A weight of 95 tonnes is moved aft through a distance of 42 m. Calculate the final drafts given that LBP is 100 m, LCF is 48 m foap and MCTC is 285 t-m.