PURPOSE: To enhance a balance of a center of gravity of a ship's hull and to provide a safe high-speed navigation by mounting a towing winch on the front of a hull, and installing a rope guide pipe for running a rope taken out from the winch through the hull.

CONSTITUTION: At a rear end of a hull 1 of an air boat B, a propeller 2 for boat propulsion and a pair of right and left rudders 3 are installed, and on a front of the hull 1, a towing winch 5, where a hand brake 10 is provided on one end and a torque open lever 11 is installed on the other end respectively, is mounted. In the hull 1, a rope suction opening 12 is provided at a little rear position of the towing winch 5, and a rope delivery opening 13 is provided at the rear end of the hull 1 respectively, between which a rope guide pipe 18 is installed. The rope suction opening 12 is fixed at the end of an arm plate 17 which is journaled to a fixed piece 16 projected on an inlet wall 15 of the rope guide pipe 18 so that it may oscillate sideways freely, and a para-glider P is connected to a rear end of a rope extending backwards from the rope delivery opening 13.