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post #1 of 4 Old 12-17-2002 Thread Starter
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How is a boat''s displacement computed? If a boat has a gross tonnage of 24,000 lbs, is its displacement the same, or is there an equation to derive a different figure?
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post #2 of 4 Old 12-17-2002
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The displacement has to at least equal the overall weight of the boat - or it will sink.

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post #3 of 4 Old 12-17-2002
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When a boat is floating, it displaces an amount of water which weights exactly equal to the weight of the boat. Hence the term: Displacement.

As far as Gross Tonnage, that figure would reference the displacement of the vessel AND the weight of the cargo the vessel can carry. That figure is used in documenting a vessel.

For more information on that aspect, check out: www.uscg.mil/hq/g-m/vdoc/nvdc.htm
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post #4 of 4 Old 12-17-2002
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It must be theoretically possible to calculate the displacement of a boat - naval architects do it all the time. The result can be numbers that are quite different from what the boat actually ends up weighing. Maybe the NA forgot to include a figure for full tanks. Maybe he left off 500 feet of chain. On bigger boats, stuff like this may make a difference of a half inch in the floating lines - no big deal. On smaller boats it can make a bigger difference, and they may go back and revise the printed numbers they publicize after they actually get a sample one to weigh.
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