The boat design that finally became the steel shortboat can cope with any amount of water on either deck.
Water spilling on to the foredeck hits the front of the the cabin, spills around and falls off.
Going downhill the water hits the back deck, tops up the ballast tank ,hits the back of the engine room and the wash board in the slide and again spills away.
The shortboat has evolved to be be impervious to the waterfalls it might meet. A submarine perhaps.
New boats should maybe aim to have some of the same qualities.