Winch mechanisms

Abstract From the Canadian patent

A winch mechanism of the deep lift type comprises a variable displacement hydraulic pump/motor which is adjusted so as to support from a ship or the like via a rope haulage mechanism a submerged load under the influence of pressurised hydraulic fluid which is stored at a substantially constant pressure in a high pressure accumulator and in a low pressure accumulator. As the ship rises and falls, forces on the submerged load are sufficient to maintain the load substantially stationary with hydraulic fluid being passed via the pump/motor between the two accumulators. Lifting is accomplished by a pump which circulates hydraulic fluid through the pump/motor.