Abstract: A lightering connection system is provided for coupling a tug boat to a barge, where the connection permits relative vertical movement between the tug and barge while maintaining horizontal movement control between the vessels. The tug boat has port and starboard retractable rams having coupler heads which engage the barge along inboard port and starboard vertical receiver channels. The coupler heads and vertical receiver channels are provided with waveform surfaces to permit interlocking engagement between the tug boat and barge. The waveform surfaces also permit smooth relative movement of the surfaces as the ram disengages in performing the lightering operation. The coupler heads and vertical channel receivers have a mating angular construction to maintain horizontal movement control between the tug and barge during the lightering operation.

Abstract: A lightering connection system is provided for coupling a tug boat to a barge, where the connection permits relative vertical movement between the tug and barge while maintaining horizontal movement control between the vessels. The tug boat has port and starboard retractable rams having coupler heads which engage the barge along inboard port and starboard vertical receiver channels. The coupler heads and vertical receiver channels are provided with waveform surfaces to permit interlocking engagement between the tug boat and barge. The waveform surfaces also permit smooth relative movement of the surfaces as the ram disengages in performing the lightering operation. The coupler heads and vertical channel receivers have a mating angular construction to maintain horizontal movement control between the tug and barge during the lightering operation.

Abstract: A hinged pawl and an emergency pawl release system for heavy duty winches such as those used to anchor semi-submersible drilling rigs. The pawl includes two sections hinged together at an overcenter knuckle joint and provided with flat bearing surfaces which hold the pawl in a rigid position engaged with a ratchet wheel on the winch drum. The pawl is normally engaged and released by a pneumatic cylinder. In an emergency situation involving a loss of electric power while the winch is heavily loaded, the pawl is collapsed about the knuckle joint by an air operated explosive actuator which applies an explosive release force to the pawl. The pneumatic control system for the explosive actuator releases both the clutch and the brake of the winch when the actuator is fired.