The QuietTorque  systems all have native regeneration.  Your propeller size and  sailing speed determine the how much power you will generate. Expect regeneration to start at about 5kts and become bankable at above 6kts.  Typically, it will serve as a supplement to other sources such as solar. When sailing, you can expect to supply your house power needs and will be putting power back into the batteries. Catamarans get the best results.