A modular lift system may include, but is not limited to: one or more lift segments each including: a lift-truss structure; and a drive shaft having at least one end-coupler, at least one lift assembly coupled to the lift-truss structure, and at least one drive segment including: a drive-truss structure; a drive motor coupled to the drive-truss structure; and a drive-coupler attached to the drive motor and configured to engage the end-coupler of the drive shaft.

A boat lift that may have a first worm screw operably connected to the drive shaft defining an axis of rotation aligned with the drive shaft and operably contacting a first worm gear, the first worm screw and the first worm gear defines a first lifting stage. The boat lift may also have a second worm screw operably connected to the first worm gear and operably contacts a second worm gear, the second worm screw and the second worm gear defines a second lifting stage. The boat lift may have a tapered roller bearing assembly that operably engages the second worm screw, the tapered roller bearing assembly has a first tapered roller bearing secured at a first location proximate a first end of the second worm screw and a second tapered roller bearing secured at a second location proximate a second opposing end of the second worm screw.

A drum hoist including a movable drum which is arranged on a main shaft with a coupling apparatus for the releasable connection of the movable drum and the main shaft, a drum wheel which is connected fixedly to the movable drum so as to rotate with it, and a coupler wheel which can be displaced axially in an engagement direction and a disengagement direction with respect to the main shaft. In order to effectively prevent undesired disengagement of a coupler wheel of the coupling apparatus without mounting additional elements, coupling elements are arranged between the drum wheel and the coupler wheel which can be engaged and disengaged, which coupling elements can be brought into and out of engagement by a rotation of the engaged coupler wheel with respect to the drum wheel by the amount of the tooth flank play between the toothing systems of the two wheels.