Marine outdrive apparatus

TLDR: In this paper, a marine outdrive attachable to the transom of a boat having an inboard engine is described, which includes a tubular support casing securable to and extendable rearwardly of the boat transom and having a ball socket at its rear end.

Abstract: A marine outdrive attachable to the transom of a boat having an inboard engine. The marine outdrive includes a tubular support casing securable to and extendable rearwardly of the boat's transom and having a ball socket at its rear end. The ball socket receives a ball at the front end of a tubular, propeller shaft carrier having a conical outer surface. A drive shaft connectable to the inboard engine is journalled in the support casing. A propeller shaft is journalled in the propeller shaft carrier and has a propeller mounted thereon at the rear end of the propeller shaft carrier. A universal joint couples the two shafts together, the center of such joint substantially coinciding with the point about which the ball pivots within the socket. Hydraulic steering cylinders are attached to the propeller shaft carrier to pivot the latter about a steering axis extending through the pivot point of the ball. A hydraulic trim cylinder extends between the transom and the propeller shaft carrier to swing the propeller shaft carrier about a laterally extending trim axis extending through the pivot point of the ball. The upper end of the trim cylinder is pivotally mounted on the transom at a location above and vertically aligned with the pivot point of the ball or at a location above and forwardly of such pivot point. Improved fins are provided on the propeller shaft carrier near the propeller to stabilize the boat. The drive shaft of the inboard motor can be directly connected to the joint or offset from the joint and coupled thereto by a vertically extending transmission.