Sailing Ship Design

Subchapter "T" Passenger Carrying Vessels

Subchapter "T" is the least onerous of US regulations governing passenger carrying vessels. To qualify as a "T-boat" a vessel must carry less than 149 passengers and admeasure less than 100 gross tons. In addition to the restriction on gross tonnage, sailing T-boats have extremely highly regulated stability. Some well-intentioned designs have largely failed as T-boats due to a lack of understanding (or a disregard for) of the regulations by the designers and builders. Some well-known sailing "T" boats are: Amistad, Pride of Baltimore II and Spirit of Massachusetts.


The Schooner Virginia

Principal Dimensions


121.8 ft



12.25 ft





154 Ltons









Sail area

6438 ft2


The Schooner Virginia is closely modeled on a 1915 Cox and Stevens pilot schooner with the same name. The new vessel will be licensed as both a small passenger carrying vessel and a sailing school ship on ocean routes. Tri-Coastal Marine will build the new schooner for the Schooner Virginia Project on site in Norfolk, Virginia. Read more about the construction and mission of the Virginia at their site.

Tonnage measurement

T-boats have to be less than 100 gross tons. That tonnage can be measured in two different ways: the "Standard" system (US only) and the Conventions system (everywhere else). While the two systems both measure internal "useable" volume and should give similar results, the "standard" system is possible to manipulate to get a lower gross tonnage. There are vessels which measure would measure 6000 GT under the Convention (i.e., rational system), but less than 100 GT under the Standard system.

A great deal of our work is reducing "admeasured" tonnage with tonnage reduction techniques permitted under the Standard system. This old system dates back before modern metal shipbuilding, and hence is very easy to game on metal ships. It is much more difficult to achieve large tonnage reduction on wooden ships.

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last updated 5/16/2002