Abstract: An elevating unit for a jack-up rig provides a pinion gear that rotates upon a support frame for engaging a toothed rack of each leg of the jack-up rig. Each pinion gear is mounted on a gear shaft that extends in opposite directions from a plane of rotation of the gear. First and second roller bearings are mounted upon the frame for supporting the pinion gear at first and second pinion gear shaft end portions. On one shaft end portion, a planetary gear box engages the shaft, the gear box being motor driven. On the opposite side of the shaft end portion a brake hub is attached to the pinion gear shaft and carries a brake drum. A brake band extends about the drum, the band being operable to frictionally engage the brake drum to retard movement of the drum, hub and pinion gear shaft relative to the frame.

Abstract: An elevating unit for a jack-up rig provides a pinion gear that rotates upon a support frame for engaging a toothed rack of each leg of the jack-up rig. Each pinion gear is mounted on a gear shaft that extends in opposite directions from a plane of rotation of the gear. First and second roller bearings are mounted upon the frame for supporting the pinion gear at first and second pinion gear shaft end portions. On one shaft end portion, a planetary gear box engages the shaft, the gear box being motor driven. On the opposite side of the shaft end portion a brake hub is attached to the pinion gear shaft and carries a brake drum. A brake band extends about the drum, the band being operable to frictionally engage the brake drum to retard movement of the drum, hub and pinion gear shaft relative to the frame.

Abstract: A boat lifting crane includes an annular ring beam mounted on the barge deck of a jack-up rig about one of the vertical openings of the rig that receives one of the legs and its elevating units. The ring provides spacing away from the leg, its opening and its elevating unit so that the ring derives all of its structural integrity from the barge or hull of the jack-up unit. The ring provides upper and lower bearing surface portions. A crane gantry extends about a selected one of the legs and its adjacent elevating units of the jack-up rig, the gantry having front and rear portions. A boom pivotally mounts to the front portion of the gantry. Roller bearings and/or other friction reduction devices on the front portion of the gantry transfer load to the ring upper surface. Hook rollers and/or other friction reduction devices on the rear portion of the gantry transfer uplift load to the ring at the ring lower surface.