Thomas Harrison Butler, DM, FRCS was a Britishophthalmologist and amateur boat designer. He published various designs of small, traditionally built yacht and was particularly concerned with the boat's handling under sail.
Harrison Butler was "a strong believer in the 'metacentric shelf formula' to achieve good balance and handling under sail. The theory held that as a yacht heels under sail, its balance will depend on the immersed form of the hull, with different sections exerting varying degrees of buoyancy and aft sections possibly being more buoyant than forward sections. Metacentric shelf analysis plots the shifts in the varying buoyancies as a net value to windward or leeward and serves as a guide to achieving equal buoyancy in the dissimilar ends of a design. The work can now be done by computer, but when it was applied by the brain, hand and eye of Dr. Harrison Butler it produced famously sweet-handling boats, in the age of heavy weather helm." In the days before computers, Harrison Butler was known to cut out paper cross sections of his hulls in order to calculate lines of symmetry and centres of mass. Boats built to his designs are noted for their sleek looks as well as their pleasant handling. He wrote two books, Cruising Yachts: Design and Performance, and An Illustrated Guide to the Slit-Lamp. and was the subject of a 1980s BBC TV documentary.
Designs
Cyclone II Bermudan Cutter A small sailing yacht. Designed 1928, circa 7 built.
Yonne Class Cutter Described by Harrison Butler as a 'sports model'. Designed 1931, circa 8 built.
Englyn Design A small sailing yacht- circa 8 built, including 'Almonde', 1933-1959
Zyklon Similar to a Falmouth Quay Punt, although smaller and with traditional rigging. Versions of the Zyklon were built by Alfred Lockhart Ltd. and known as the 'Z' 4-tonner. Circa 45 built.
A was formed in 1973 for anyone interested in his designs. It aims to keep track of Harrison Butler boats worldwide and help owners keep in touch. It holds two meetings and produces two newsletters annually.
Trivia
Harrison Butler was the father-in-law of actress Joan Hickson.