A boat lift includes posts and linear actuators, each attached to one of the posts. Each linear actuator includes an extendable and retractable member oriented for extension and retraction substantially parallel to the post. Ends of a first pair of the extendable and retractable members are connected to a first carrier, and ends of a second pair of the extendable and retractable members are connected to a second carrier. A cradle or platform is supported by the first and second carriers. The boat lift may be supported by the ground, by a structure, for example, a dock, a sea wall or a wall of a boat house, or by pontoons.

A shipyard including a shiplift platform that is capable of being raised above yard level for maintenance is provided. Hoists are coupled with the shiplift platform, and jacks are coupled with the hoists. The jacks are capable of lifting the hoists relative to the yard, and are capable of lifting the shiplift platform above the yard level.

A shipyard including a shiplift platform that is capable of being raised above yard level for maintenance is provided. Hoists are coupled with the shiplift platform, and jacks are coupled with the hoists. The jacks are capable of lifting the hoists relative to the yard, and are capable of lifting the shiplift platform above the yard level.

A buoyancy tank for a portable floatation apparatus which allows for the elevation of a watercraft above a water-line and which allows for the removal of the watercraft from a body of water. The buoyancy tank has at least one and/or a plurality of integrated cylindrical structures which supports the floatation apparatus in transport and storage. The integrated cylindrical structures provide sufficient support to allow the removal of the floatation apparatus by use of a boat lift and further provide sufficient support to allow a watercraft to be stacked on top of the floating apparatus while the floating apparatus is stacked on top of the floating apparatus for the purposes of storage. A plurality of said buoyancy tanks may be connected to the portable floatation apparatus by use of connecting means. The portable floatation apparatus should have a pumping device which pumps a sufficient volume of air into a plurality of the buoyancy tank which is effective to selectively and conveniently elevate a watercraft above a water line.

A buoyancy tank for a portable floatation apparatus which allows for the elevation of a watercraft above a water-line and which allows for the removal of the watercraft from a body of water. The buoyancy tank has at least one and/or a plurality of integrated cylindrical structures which supports the floatation apparatus in transport and storage. The integrated cylindrical structures provide sufficient support to allow the removal of the floatation apparatus by use of a boat lift and further provide sufficient support to allow a watercraft to be stacked on top of the floating apparatus while the floating apparatus is stacked on top of the floating apparatus for the purposes of storage. A plurality of said buoyancy tanks may be connected to the portable floatation apparatus by use of connecting means. The portable floatation apparatus should have a pumping device which pumps a sufficient volume of air into a plurality of the buoyancy tank which is effective to selectively and conveniently elevate a watercraft above a water line.

A connect and disconnect assembly may have a first rotatable shaft and a second rotatable shaft aligned along a rotational axis. The assembly may also have a connect and disconnect device including one or more cams for selectively connecting and disconnecting the first rotatable shaft to and from the second rotatable shaft. A ship-lift bogie may include the connect and disconnect assembly.

A free-floating watercraft lift includes a plurality of pairs of tanks each having a first tank and a second tank, a plurality of lower frame assemblies, first and second upper frame assemblies, and a control system comprising at least one blower for selectively providing air to each of the first and second tanks of the plurality of pairs of tanks. The first and second tanks of each pair of tanks are laterally spaced-apart and facing one another. Each one of the lower frame assemblies connects the first tank and the second tank of a separate one of the pairs of tanks The first upper frame assembly connects each of the first tanks of the plurality of pairs of tanks and the second upper frame assembly connects each of the second tanks of the plurality of pairs of tanks.

A free-floating watercraft lift includes a plurality of pairs of tanks each having a first tank and a second tank, a plurality of lower frame assemblies, first and second upper frame assemblies, and a control system comprising at least one blower for selectively providing air to each of the first and second tanks of the plurality of pairs of tanks. The first and second tanks of each pair of tanks are laterally spaced-apart and facing one another. Each one of the lower frame assemblies connects the first tank and the second tank of a separate one of the pairs of tanks The first upper frame assembly connects each of the first tanks of the plurality of pairs of tanks and the second upper frame assembly connects each of the second tanks of the plurality of pairs of tanks.

A buoyancy tank for a portable floatation apparatus which allows for the elevation of a watercraft above a water-line and which allows for the removal of the watercraft from a body of water. The buoyancy tank has at least one and/or a plurality of integrated cylindrical structures which supports the floatation apparatus in transport and storage. The integrated cylindrical structures provide sufficient support to allow the removal of the floatation apparatus by use of a boat lift and further provide sufficient support to allow a watercraft to be stacked on top of the floating apparatus while the floating apparatus is stacked on top of the floating apparatus for the purposes of storage. A plurality of said buoyancy tanks may be connected to the portable floatation apparatus by use of connecting means. The portable floatation apparatus should have a pumping device which pumps a sufficient volume of air into a plurality of the buoyancy tank which is effective to selectively and conveniently elevate a watercraft above a water line.

A buoyancy tank for a portable floatation apparatus which allows for the elevation of a watercraft above a water-line and which allows for the removal of the watercraft from a body of water. The buoyancy tank has at least one and/or a plurality of integrated cylindrical structures which supports the floatation apparatus in transport and storage. The integrated cylindrical structures provide sufficient support to allow the removal of the floatation apparatus by use of a boat lift and further provide sufficient support to allow a watercraft to be stacked on top of the floating apparatus while the floating apparatus is stacked on top of the floating apparatus for the purposes of storage. A plurality of said buoyancy tanks may be connected to the portable floatation apparatus by use of connecting means. The portable floatation apparatus should have a pumping device which pumps a sufficient volume of air into a plurality of the buoyancy tank which is effective to selectively and conveniently elevate a watercraft above a water line.