Abstract: An apparatus is for supporting a marine engine and has a transom bracket having a body section, a head section extending transversely relative to the body section, a neck section disposed between the body section and the head section, and a transition portion along an inside surface of the neck section. A reinforcement member is connected to the neck section and relieves tensile stress on the transition portion when the transom bracket supports the marine engine.

Abstract: A marine propulsion drive unit is provided with two energy absorbing structures, one comprising a crushable or deformable nose cone or leading edge of a driveshaft housing and the other comprising a frangible interface that allows the drive unit to separate from the hull of a marine vessel. The crushable or deformable nose cone is configured to absorb energy at relatively low impact velocities with submerged structures and the frangible interface is configured to absorb energy and then detach from the hull of the marine vessel at higher impact velocities.

Abstract: A marine drive has a break-away mount mounting first and second sections of the drive and breaking-away in response to a given underwater impact against the second section to protect the first section and the vessel.

Abstract: A torque transfer mechanism for a marine propulsion system provides a connector mechanism, a first torque transfer mechanism, and a second torque transfer mechanism. A plurality of rods can provide the first torque transfer mechanism and a polymer component is shaped to provide the second torque transfer mechanism. All torque below a preselected magnitude is transferred through the first torque transfer mechanism and, for magnitudes of torque above the threshold, torque is transferred by both the first and second torque transfer mechanisms. The connector mechanism has an outer surface that is not used to transfer torque between it and an inner hub of a propulsor.

Abstract: A propeller device is provided with vent apertures and plugs which fit into the vent apertures to be retained in position during use of the propeller device. The vent plugs are provided with openings therethrough so that fluids can flow from a region within a hub of the propeller device to a region proximate the outer cylindrical surface of the hub. The fluids flowing from the internal portion of the hub flow towards regions of low pressure near the propellers. The plugs can be changed to modify the size of the ventilation aperture without having to change the propeller device itself. One embodiment of the plug is provided with a moveable cover that closes the opening progressively in response to increasing rotational speed of the propeller device.

Abstract: A shock absorbing drive sleeve (402, FIGS. 28+) mounts a marine drive propeller (12) to a propeller shaft (22) and has an asymmetric spring rate such that the sleeve has a higher spring rate and greater torque bearing capability for the forward boat direction, and a softer spring rate and greater shock absorption for the reverse boat direction, to protect the weaker reverse drive components of the gear train.