I use 4 x AA NiMH with my kit plastic yachts, with a Y lead. so that the RX gets 4.8V from the Hitec servo. (Voyager,Seawind,Victoria)
With the IOM, 5xAA NiMH, Y lead, Whirlwind winch.
Marblehead, as above, Hitec winch.

Hope this is what you are looking for.

Edward.