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, and was designed for small vessels, such as
yachts. It was originally used for calculating the port dues for yachts; the formula was also used in some early
handicapping systems for
yacht racing.[1]
The calculation of Thames Tonnage uses the following formula:
where:
length is the length, in
feet, from the stempost to sternpost;