Abstract: The propellor guard described herein is designed primarily for the protection of manatee but is also useful in protection against injury to other animals and larger fish which might come in contact with a boat's propellor. This guard is tapered toward substantially a point at the front end and is substantially circular at the rear end so as to encircle the region in which the propellor is rotated. The guard has a V-bracket at the front which is securely pressed against a propellor support and is supported at the rear in the circular portion by a pair of clamps which engage and are bolted tightly onto the cavitation plate.