Apparatus and method for reducing heave motion in a load suspended from a vessel mounted crane. The apparatus comprises: a main chassis; a drive assembly mounted to the main chassis and comprising a drive gear or pinion 235; a geared rotating mechanism 160 translatably (in rotation) disposed in the main chassis, and running along a circumferential path; and a lift wire, rope or chain 170 secured to the geared rotating mechanism. The drive gear or pinion engages the geared rotating mechanism such that rotation of the drive gear or pinion (such as by a motor 220) is coupled to translation of the rotating mechanism in the main chassis, thereby lifting or lowering the lift wire, rope or chain. Control circuitry is operative to command the drive assembly to cause the geared rotating mechanism to translate in the main chassis at least in part based on the heave motion detected by a sensor. A second drive assembly, a second drive gear or pinion, and a second geared rotating mechanism may be provided within the main chassis, and controlled by the control circuitry. The apparatus provides active heave compensation.
Active heave compensation apparatus
2018-10-31
Patent
Electronic Resource
English