Power, control & automation
Hydraulic constant-tension winch
Robust, reliable constant tension for wire rope and heavy lifts, held by the pressure differential across the winch motor, with no electronics in the control loop.
A hydraulic constant-tension winch holds line tension by maintaining a set pressure differential across the A and B ports of its drive motor: the hoist-pressure relief is set to the line load, the motor delivers a steady torque and the line is held taut as the vessel moves, paying out or hauling in to keep tension constant. It is one of the most robust and dependable ways to hold tension offshore.
What it’s good at
- Robust and simple – tension is held hydraulically, with no electronics in the control loop; counterbalance / over-centre valves give dynamic braking and hold the load on loss of pressure, and a spring-applied, hydraulically-released brake backs it up.
- Reliable for heavy duty – well suited to wire-rope handling, heavy lifts and seabed-extraction “over-pull”, where high, dependable tension is exactly what’s wanted.
- Operator-trimmed setpoint – the holding tension can be set and trimmed up or down to suit the operation.
Where its limit is – and what to use instead
Because the motor torque reaches the rope through a gearbox and bearings, friction sets a high floor on the lowest tension it can hold steadily. That makes it ideal for wire rope and heavy lifts, but too coarse for delicate lines, umbilical, hoses and electrical umbilical need lower, gentler tension than a pressure-differential system can resolve. For those duties we use our active constant-tension winch, which measures true line tension with a load cell and closes the loop on it to achieve very low, well-controlled tensions.
Line pull, tension range and drum sizing engineered to the duty and confirmed at enquiry. Designed to recognised offshore lifting and marine-operations standards.