An improved lift boat includes a hull, a plurality of legs (preferably three), a plurality of pads, one pad attached to each leg, and a jacking mechanism for moving each upward and downward. Recesses in the hull receive the pads when the lift boat is underway. Preferably, the total bottom surface area of the pads is at least 30% of the surface area of the deck of the lift boat Preferably, the total bottom surface area of the pads is large enough such that, when the boat is loaded to capacity and is jacked up, the pads exert pressure of less than 7 p.s.i. on the sea floor. Preferably, the pads are partially recessed into the hull and extend laterally outward from the hull when the boat is underway to provide increased stability to the lift boat when it is underway.
1. A lift boat comprising:
a) a hull having a deck surface, port and starboard sides, bow and stern portions, a hull periphery, a hull centerline and a hull bottom, each said port and starboard side extending generally between the deck and bottom, the bow portion having a rake portion;
b) a plurality of legs movably attached to the hull;
c) each leg having a jacking mechanism for moving the leg upward and downward relative to the hull; and
d) a plurality of pads, one pad attached to each leg, including a pair of forward leg pads and an aft leg pad next to the vessel stern portion and closer to the hull centerline than the forward leg pads;
e) a plurality of recesses in the hull for receiving the pads when the lift boat is underway, wherein the lift boat has a deck surface area which is the surface area of the top of the hull as viewed in plan, at least two of the pads extending laterally of the deck surface area;
f) wherein two of the recesses include an opening in one of the sides through which a pad extends beyond the hull periphery during use when the boat is underway and the legs are in the up position; and
g) a propulsion system for self-propelling the hull, including a pair of propulsion units positioned on opposite sides of the aft leg pad.
2. The lift boat of claim 1 , wherein the pads are partially recessed into the hull and extend laterally outward from the hull when the boat is underway.