89 sailfish, bracket twin 200 hpdi's. mine are also under water at rest however i trailer that beast so i sleep at night. the floor drains have a check ball under the strainer cap. that keeps the floor somewhat dry while fishing in the waves. at the dock if the boat had a scupper hose failure, she would take water till it hit bottom. the check ball is at the wrong end of the hose. those (ugly) but functional exterior clear plastic check ball, i think would actually stop water intrusion completely. i would install them if i where slipping the boat. i have heard of guys when doing a transom rebuild, of cutting floor level scuppers (oval) and glassing thru to the outer hull using a flex hose that exits above the water line. much like carolina classics and albemarle's have.