Boats can not manage in a rough sea, but if you could drop the boats ANCHOR very low in the ocean a couple yards below and ride/propel that way, the rough waves of a rough seas will not capsize the boat (think about it as having strong roots)....Because noticed, the rough waves are coming from the Top surface of the sea not the bottom part, the bottom part is calm...So if you can come up with a way, system, creation that will employ or mimic this mechanism you will be able to ride in rough seas and your ship will not capsize...