I asked another question in a previous thread, but this is a new issue so here's a new thread: Basically I need to design some kind of waterproof shaft seal for the use of an underwater ROV. Following some earlier advice, I looked into the Parker O-ring Handbook and found the easiest way is just to have o-rings complete the seal, recessed into grooves. The operating depth I expect to be working in will be no more than 4 meters, so it will be fairly shallow... will this simple o-ring seal be enough to keep water out? And if so, any advice as to how I should go about machining this seal? It is going to be for a stepper motor that will let my thruster assembly rotate. Thanks!