kneeboard

A short (often less than 6'), broad (sometimes extremely broad) surfboard designed to be ridden in the surf in a kneeling position, and often having traction pads in the central area as an alternative to wax, to help the knees grip the deck

A clipboard carried in the lap of an airplane pilot, on which basic flight data is recorded.

A short wakeboard designed to be ridden in the kneeling position.

to surf or water-ski using a kneeboard