Transom-mounted generators, such as those produced by Watt & Sea, are capable of producing large amounts of power with minimal drag and can be lifted clear of the water when not in use. The company’s "cruising" units are rated at either 300 or 600 watts, depending on the model chosen. The larger of these produces 120 watts of power amps at just five knots of boat speed, rising to more than 250 watts at 7.5 knots.
Over a 24-hour period that represents a significant amount of power that could alone run the majority of systems aboard many 50-60ft yachts, including watermakers, pilots, lights, electronics, refrigeration and water heating. Watt & Sea’s transom mounted hydrogenerators range between $3,500 - $5,000.
Watt & Sea also has a new hull-mounted option. The "Pod" is rated at 600 watts and runs about $4,400. The advantages of the pod over the transom mounted generators are it is invisible from the surface, no complicated handling up or down, easy start-up, & electrical output is similar to their transom mounted models
Another option is a hybrid drive system with a regenerating function via the boat’s main propeller. Advantages include an absence of peripheral parts attached to the transom that may be susceptible to damage, or detract from a yacht’s aesthetics.