[PSUBS-MAILIST] Electrical Through Hull

I am planning on building an ROV sometime in the near future, and as I was sketching out the plans I noticed that I was running cables right through the sides of some of the components without giving much thought to how exactly electrical through hulls are constructed. So I went surfing the net and the archives for this kind of information but most of the information out there is geared towards professionals with higher education in the field, not high school kids who are unflamiliar with some of the terminology.

I know that manned submersibles face must adress this matter as well, so what sort of hard ware is used to run electrical cables through the side of the boat and then connect to an electrical device outside of the main body of the craft.