I want to build a homemade WTC. A drain pipe with custom made plastic covers on both ends and a brass tray which will fit to the diameter of the pipe. What I need is what is the optimal layout of the tray.I will purchase shaft, propeller and seals from subconcepts. Does anyone have drawings for covers and the tray that will hold the servos battery and electronics. First I want to build a small pool sub without ballast system.