Thames Measurement, also known as Thames Tonnage, is a system for measuring ships and boats. It was created in 1855 as a variation of
Builder's Old Measurement by the
Royal Thames Yacht Club
The Royal Thames Yacht Club (RTYC) is the oldest continuously operating yacht club in the world, and the oldest yacht club in the United Kingdom. Its headquarters are located at 60 Knightsbridge, London, England, overlooking Hyde Park. The club ...
, and was designed for small vessels, such as
yacht
A yacht is a sailing or power vessel used for pleasure, cruising, or racing. There is no standard definition, though the term generally applies to vessels with a cabin intended for overnight use. To be termed a , as opposed to a , such a pleasu ...
s. It was originally used for calculating the port dues for yachts; the formula was also used in some early
handicapping systems for
yacht racing
Yacht racing is a sailing sport involving sailing yachts and larger sailboats, as distinguished from dinghy racing, which involves open boats. It is composed of multiple yachts, in direct competition, racing around a course marked by buoys or ...
.
The calculation of Thames Tonnage uses the following formula:
:
where:
*''length'' is the length, in
feet
The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made ...
, from the stempost to sternpost;
*''beam'' is the maximum
beam, in feet.
This can be simplified as:
:
See also
*
Tonnage
Tonnage is a measure of the cargo-carrying capacity of a ship, and is commonly used to assess fees on commercial shipping. The term derives from the taxation paid on ''tuns'' or casks of wine. In modern maritime usage, "tonnage" specifically r ...
References
{{Yacht handicapping rules
Sailing rules and handicapping
Volume
Mass
Ship measurements