Many hydraulic winches can be supplied with a constant tension facility to provide safe operation where loads may exceed a given criteria.

An external relief valve is set to provide a pre-determined load. The winch will stall if the load is increased and will even pay-out if the load increases even more. When the load reduces to below the relief valve setting the winch will continue to haul.

Modern advances with electric motors running with inverter or frequency drives are now being used as constant tension winches.