Hot water was an option on the original boat in 1972. I thought about installing it on mine, under the forward berth aft of the main water tanks, where there would be plenty of room for a good sized tank. I decided instead just to use the stove for hot water; somebody posted a link a while back for a stainless steel shower device that you heat over the stove and carry into the head for a shower.
Gareth
Freyje E35 #241 1972