Exam Question
A ship 96m long is floating at 5m fwd draft and 6.4m aft draft, MCTC 180 tm, TPC 16. COF is 2m abaaft of midship. Find the location where a weight of 50t should be placed as to keep the aft draft constant. (16)
Class 4 (4th Engineer)
SC&S
📅 Nov 2023
Reference Answer
### Principle of the Calculation
To maintain the aft draft at a constant value while loading a weight, the trimming effect must precisely counteract the effect of parallel sinkage at the aft perpendicular. When a weight is loaded, it causes a uniform increase in draft (parallel sinkage). To negate this increase at the aft end, a trimming moment must be created that causes the stern to rise by an amount exactly equal to the sinkage. This requires loading the weight at a specific longitudinal position forward of the Centre of Flotation (COF), thereby creating a trimming moment by the head.
### Given Data
* Length of ship (L): 96 m
To maintain the aft draft at a constant value while loading a weight, the trimming effect must precisely counteract the effect of parallel sinkage at the aft perpendicular. When a weight is loaded, it causes a uniform increase in draft (parallel sinkage). To negate this increase at the aft end, a trimming moment must be created that causes the stern to rise by an amount exactly equal to the sinkage. This requires loading the weight at a specific longitudinal position forward of the Centre of Flotation (COF), thereby creating a trimming moment by the head.
### Given Data
* Length of ship (L): 96 m
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