Fin keel

The fin keel is a stationary foil positioned amidships and projecting downwards under the hull of a sailing vessel. A fin keel is relatively short in a fore-aft direction, and relatively deep, located near the center of the boat. A fin keel is a fixed element, unlike a centerboard, which is retractable. The design purpose of the fin keel^[1] is to provide lateral resistance to wind forces applied to the boat via the sails and to facilitate the placement of ballast below the hull while presenting less wetted surface area than a full keel, which helps to reduce drag and leeway. The fin keel was invented by James Brown Herreshoff (1834–1930).^[2]

References

1. https://www.diva-portal.org/smash/get/diva2:737567/FULLTEXT01.pdf ^{[bare URL PDF]}
2. Hartford Courant (December 8, 1930). "Herreshoff, One of Noted Family Died – Inventor of Fin Keel for Racing Yachts Succombs at Home in Riverdale, N.Y., Aged 96". Vol. 93. Hartford, Connecticut. p. 4. Retrieved February 14, 2021 – via Newspapers.com.