Who invented the modern surfboard fin in the 1930s?

Tom Blake invented the modern surfboard fin in the 1930s.

Blake developed a fixed fin for surfboards after experimenting with ways to improve directional stability. His design, introduced in 1935, was attached to the underside near the tail and helped prevent a board from sliding sideways during turns.

Before fins became standard, surfers controlled direction mainly by shifting their weight and using their feet or hands in the water. Blake’s innovation made boards easier to steer and influenced nearly every later surfboard design.

The fin is sometimes confused with the later three-fin thruster system, which Simon Anderson invented in 1980. Blake did not invent that setup; his earlier contribution was the single fin that established the basic principle of underwater lateral control.