Abstract: A mounting base for removably securing the base portion of a fishing rod holder to a boat having a rope cleat thereon and including a mounting plate for receiving the base portion and a sole plate extending therefrom, the sole plate having a recess formed therein, a movable detent secured in the recess, a spring acting on the sole plate and the detent member so as to cause the detent to normally project above the surface of the sole plate for securing the mounting plate in position beneath a rope cleat while enabling the detent member to be depressed against the urging of the spring to a point at or beneath the surface of the sole plate and thereby enable withdrawal of the mounting base from beneath the rope cleat.