The implement appears to have been affixed to a wall with the handle portion of the paddle facing upwards: observe the nail which is still present, as well as the three other holes reminiscent of nail holes. A stick or a hook would then perhaps be inserted into the metal opening. A hook seems more likely, as a straight pole would not rest very securely in the metal holder, given its size (about 4 inches?). Thus, an umbrella holder perhaps?