In 1968, American Hugo Vihlen sailed from Casablanca to Florida in a boat 5 feet 11 inches long.
In 1992, Englishman Tom McNally sailed from Portugal to Fort Lauderdale in a boat 5 feet 4.5 inches long.
In 1993 Vihlen reclaimed the record by sailing from Newfoundland to Falmouth in a boat 5 feet 4 inches long.
“Tom McNally made plans to fight back with a minuscule three-foot, eleven-inch boat, and when Vihlen later heard about that he announced his intention to build a three-foot, eight-inch aluminum boat,” writes William Longyard in A Speck on the Sea (2003). “The battle would continue between these two friends and rivals.”
(Thanks, Dave.)