Autopilots are under constant use on long passages, consuming considerable power and requiring frequent engine running to recharge the batteries. Harnessing the energy of moving water in the wake of a sailing vessel is not a new idea, but The Water Drive is unique. It uses hydraulics to drive the autopilot, thus relieving one of the largest electrical draws offshore, and generates 12-volt power at the same time. The Water Drive employs a small turbine propeller deployed from the stern of the boat on a length of rope. The propeller spins in the water causing this rope to rotate, turning a hydraulic pump and a generator. The hydraulic pump, in turn, drives a ram connected to the quadrant of the rudder, which then steers the vessel. The result is that the existing autopilot provides only a tiny steering Owner installation, maintenance and overhaul is encouraged, an important consideration when faced with remote destinations where qualified service may be hard to come by or nonexistent. The hydraulic unit is lashed to the aft rail and a roll of flexible tubing is run through the deck to the hydraulic ram at the rudder quadrant. The selector switch is inserted in the existing autopilot's output cable and then to its motor or actuator. Tubing and wires are included. Ordinary motor oil is used to drive the hydraulic unit, alleviating the headaches of purging a straight hydraulic fluid system of air. The Water Drive is also appealing to long distance cruisers because it lightens the load on expensive autopilot equipment. Autopilots driven by electric motors have limited lifespans The most apparent drawback to the system is that unless the vessel is underway, electricity will not be produced. Additionally the propeller is vulnerable to collisions with underwater objects and may be fouled by heavy seaweed or other flotsam. It's also a great lure for large fish. There are six different models for vessels 32 to 80 feet in length. Prices start at $1,899 and go to $5,581. A three-year warranty covers defects in materials or workmanship. If energy conservation on extended voyages are on your sailing itinerary, the WaterDrive may be a welcome addition to your electrical and autopilot systems. |