Calculating boat size for purposes of documentation
If you want to document your boat with the U.S. Coast Guard, she must measure at least 5 tons net. For practical purposes regarding pleasure boats, net tonnage is understood to be 9/10 of gross tonnage.To calculate gross tonnage, take half of the overall length L times overall breadth B times depth D (the internal measurement of the hull, not the draft), all in feet, divided by 100. In other words:½ (L x B x D ÷ 100).
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| Clockwise from top left: Bulwagga; spade; barnacle. |
Roughly speaking, 5 net tons corresponds to a moderate-displacement boat about 30 feet in length. A heavy-displacement, long-keeled cruising boat could be as little as 25 feet overall but still have sufficient volume below decks to qualify for federal documentation.A documented vessel must be owned by a U.S. citizen. The captain (and any other officer) must be a U.S. citizen as well, although crew members need not be. Documentation gives you the legal right to fly the special U.S. Yacht Ensign (in home waters only), an authority that is not officially granted to other yachts— although many wear it anyway.A documented yacht’s title is also proof of ownership because it records the liens, mortgages, and other financial liabilities (if any) that she carries.See also
Flags; Registration.
