PURPOSE: To obtain a sufficient restoring property even though a lifeboat is turned over and flooded in a stormy sea, by composing the center axis of a tubular hull eccentric from the center of a float supporter, so as to maintain the hull horizontal by the principle of pendulum.

CONSTITUTION: At the bow and the stern of a hull 1, float supporters 2a and 2b are installed rotatable respectively. Each of the float supporters 2a and 2b is composed of three arms 3 extending radially form the center O, and the center O is made eccentric upward as the amount a from the center axis O' of the hull 1. Furthermore, between the pair of float supporters 2a and 2b, cylindrical rolling floats 4 are installed rotatable. Since the center axis O', of the hull 1 is eccentric from the centers O of the float supporters 2a and 2b, the hull 1 can maintain the horizontal posture constantly by the principle of pendulum.