RC boats operate the same as cars and trucks only they go on water of course and the electric versions are less likely to quit out in the middle of the lake or pond, as long as there is good seal on the radio equipment. The cost is somewhat less because they are not going to get the abuse of a RC car or truck, but I would still consider buying an extra battery and a fast charger.
Here are some recommendations for boats:
Nitro (gas) boats:
