Something does not add up on the hot water. I assume this was a catamaran. Each engine and hull would have a associated hot water tank which is heavily insulated. The water can be heated by a electric element or running the engines. The electric elements are almost never used in the BVI because they draw a lot of Amps and can overload show power or a genset if the AC is running. Normal engine use to dock or moor a boat should however heat the tanks and provide adequate hot water for reasonable showers all evening. Each hulls system is normally independent of the other.
Having said all of the above the water temp in the tanks is normally fine for showers even when the hot water tanks are empty. Certainly worst case it would be a very minor distraction.
G