Friday the 13 th and I dont go out ,so on this early . Well thanks for the replys but I am in the dark ,,ive got this acrilic tube ,it fits the gear that came with the hull ,so that I assume is the start for a water tight compartment to hold the electrics etc , then do I have to use the same ,only blank off to use a ballast system ,like to pump water into /out of tube ,what i need to help me ,can anyone give us /send us ,some of the drawings that are for beggineers as I really am ,not kidding ,clueless ,the list of things I can fix /repair is big but this is a very different item .the pics ive seen of what you guys are into ,VERY professional .,could be M O D for all I know . thanks in anticipation,Dave .