Patent ID: 6926260

Claim:
A hoisting device ( 10 ) for a vessel ( 12 ) comprising: a. a base structure ( 14 ) connected to the vessel having a top side ( 16 ) provided with fixed cable blocks ( 20 ) with pulleys ( 22 ); b. a trolley ( 24 ) connected to a cable pulley block ( 26 ), which is movably fixed on the base structure ( 14 ), on a top side ( 28 ) connected to the cable pulley block ( 26 ) with pulley ( 27 ), and on a bottom side ( 30 ) to mechanism ( 32 ) for gripping a load ( 34 ); c. a compensator ( 36 ) having a first end ( 38 ) and a second end ( 40 ), which is at the second end ( 40 ) connected to pulleys ( 42 ) wherein the compensator second end ( 40 ) is movable with respect to the first end ( 38 ); d. a hoisting mechanism ( 44 ), at least equipped with a hoisting cable ( 46 ) and a winch ( 48 ), wherein the hoisting cable ( 46 ) is guided over the cable pulleys ( 22 ), ( 27 ) and ( 42 ) connected to the base structure ( 14 ), the compensator ( 36 ) and the trolley ( 24 ), and is adapted to move the trolley ( 24 ) relative to the base structure ( 14 ) with the aid of the winch ( 48 ); and wherein the hoisting cable ( 46 ) is guided over the cable pulleys ( 22 ), ( 27 ), ( 42 ) so that force can be exerted upon the hoisting cable ( 46 ); and e. a secondary compensator ( 49 ) comprising: i. a second fixed cable blocks ( 50 ) with pulleys ( 52 ) connected to the base structure ( 14 ); ii. a second cable pulley set ( 54 ) connected to the compensator second end ( 40 ); iii. a secondary hoisting mechanism ( 72 ) connected to the vessel ( 12 ); iv. a second connecting cable ( 70 ) guided over the pulleys ( 52 ), ( 54 ), ( 58 ) of the vessel ( 12 ), the compensator ( 36 ) and the movable cable block ( 56 ) and is adapted to move the compensator second end ( 40 ) with the aid of the secondary hoisting mechanism ( 72 ); and wherein the second connecting cable ( 70 ) is guided over pulleys ( 52 ), ( 54 ), ( 58 ) so that force can be exerted upon the compensator second end ( 40 ); and v. a sensor to detect the tension in hoisting cable ( 46 ) or the movement of the vessel ( 12 ) connected to a controller to control secondary hoisting mechanism ( 72 ).