Abstract: Watersport board fins with fin retention systems and associated watersport boards and methods. A fin includes a hydrodynamic blade and a fin base extending from the hydrodynamic blade. The hydrodynamic blade defines a fin plane and includes a leading edge, a trailing edge, and a foil surface. The fin further includes a fin retention system with a selective retention system that includes a retainer and an actuator coupled to the retainer via a pivot shaft. The actuator forms a portion of the hydrodynamic blade when the selective retention system is in a locked configuration and is configured to rotate away from the fin plane when the selective retention system transitions from the locked configuration to an unlocked configuration. The retainer is configured to rotate away from the fin plane when the selective retention system transitions from the unlocked configuration to the locked configuration.

Abstract: An air vent for a floating board such as a paddleboard, which includes a tubular vent member that has an upper end and a lower end. A mounting supports the tubular vent member in a vertical orientation with the upper end of the tubular vent member protruding above an upper surface of the floating board. The tubular vent is mounted in a central zone comprising a central one third of the floating board, and along a crown positioned between a first side and a second side of the floating board.