A catamaran lifting apparatus is disclosed for lifting objects in a marine environment. The apparatus includes first and second vessels that are spaced apart during use. A first frame spans between the vessels. A second frame spans between the vessels. The frames arc spaced apart and connected to the vessels in a configuration that spaces the vessels apart. The first frame connects to the first vessel with a universal joint and to the second vessel with a hinged connection. The second frame connects to the second vessel with a universal joint and to the first vessel with a hinged or pinned connection. Each of the frames extends upwardly in an inverted u-shape, providing a space under the frame and in between the barges that enables a marine vessel to he positioned in between the barges and under the frames.

Modifications to the lifting structure of prior art boat lifts permit the addition of support and drive rollers and associated drive mechanisms that may be used to displace the bow (or stern) of a raised boat over an adjacent barrier such as a sea wall, dock, or bulkhead.

Modifications to the lifting structure of prior art boat lifts permit the addition of support and drive rollers and associated drive mechanisms that may be used to displace the bow (or stern) of a raised boat over an adjacent barrier such as a sea wall, dock, or bulkhead.

A floating boat lift having flotation tanks positioned under sides of a frame of the boat lift and a transverse flotation tank that communicates with the flotation tanks. Water flow is regulated so that tanks fill from near the center of the boat lift. Water is accepted into or pumped from the flotation tanks, allowing the frame of the boat lift to fall or rise relative to the surface of the water.

A floating boat lift having flotation tanks positioned under sides of a frame of the boat lift and a transverse flotation tank that communicates with the flotation tanks. Water flow is regulated so that tanks fill from near the center of the boat lift. Water is accepted into or pumped from the flotation tanks, allowing the frame of the boat lift to fall or rise relative to the surface of the water.

A watercraft lift with rearward and forward lateral beams, left and right side longitudinal side beams, a pair of left side lifting arms, a pair of right side lifting arms supporting at their upper ends left and right side watercraft supports, and left and right side actuators pivotally attached to the left and right side rearward lifting arms. In one embodiment the left side rearward lifting arm and the left side actuator rotate about their pivotal attachments to the longitudinal left side beam in a left side plane, and the right side rearward lifting arm and the right side actuator rotate about their pivotal attachments to the longitudinal right side beam in a right side plane.

A watercraft lift with rearward and forward lateral beams, left and right side longitudinal side beams, a pair of left side lifting arms, a pair of right side lifting arms supporting at their upper ends left and right side watercraft supports, and left and right side actuators pivotally attached to the left and right side rearward lifting arms. In one embodiment the left side rearward lifting arm and the left side actuator rotate about their pivotal attachments to the longitudinal left side beam in a left side plane, and the right side rearward lifting arm and the right side actuator rotate about their pivotal attachments to the longitudinal right side beam in a right side plane.

A lift system for watercraft comprising a fixed frame, at least one support member, a first movable frame, a second movable frame, and at least one actuator member. The at least one actuator assembly comprises a cylinder and a rod arranged in retracted and extended positions relative to the cylinder. The first and second lower axes are parallel and define a reference plane. When the rod is arranged in the extended position relative to the cylinder, the at least one support member is in a lowered position relative to the fixed frame. When the rod is arranged in the retracted position relative to the cylinder, the at least one support member is in a raised position relative to the fixed frame. In the lowered position, the first attachment point is below the reference plane. In the raised position, the first attachment point is above the reference plane.

A boat lift drive for connection to a winch having a winch shaft. The boat lift drive includes a power unit, a drive train engaged to and being driven by the power unit, and a drive shaft engaged to and being driven by the drive train. The drive shaft in turn is engaged to and drives the winch shaft. The drive train includes a seat with a frustoconical section and the drive shaft includes a head with a frustoconical section. The frustoconical sections are press fit into each other. This frustoconical engagement provides a great amount of torque for lifting boats.

A boat lift with hydraulically or mechanically actuated arms which self-installs a fitted three-dimensional boat cover on a powerboat. The control logic of the system allows for cover operation only when the lift is raised. A spring-tensioned roller keeps the cover tight and self-rolls the cover on the roller when the actuated arms are pivoted forward. The roller is hidden behind the boat in cover-on position. A slip clutch prevents the torsion spring from being over tightened. The forward position of the roller is adjusted by adjusting the hydraulic cylinder length. The rearward position of the roller is adjusted by limiting the retracted position of the hydraulic cylinder. A non-hydraulic embodiment actuates the cover when the lift is operated.