"Self righting is not new, been around for years. designed a self righting vessel back in the late 80's www.seaboats.net/16.9m-pilot-boat-xidp1407126.html  A low CG is only part of the equation to self righting, you need to look at the cabin volume and treat it as the hull of the vessel when its upside down with a high CG, so it will re capsize its self and upright to the correct position. The exhaust systems are general designed with a very large muffler, that they operate upside down and water does not flow backwards due to a flap inside. Also the air intake system will have flaps which shut off once the vessel passes horizontal. "