OK, I promised previously to bring some information regarding the actual equipment used by the US Navy SEALs for diving purposes. So I have been performing a little research and have discovered that the SEALs use three separate types of diving rig.

Firstly they use a standard open circuit system, this is pretty much the same as the dive kit I used when I go scuba diving myself. It consists of a tank of compressed air strapped to a BCD (combined equipment rig and buoyancy aid). The air is delivered via a regulator and is also connected to the BCD so that it may be inflated by air from the tank to add buoyancy. Anybody who has been scuba diving will recognise this kind of setup.

SEALs also use re-breathing apparatus, known as a closed circuit Oxygen system, this is also something I have tried out myself, this is actually a very dangerous form of diving, you must remain in shallow water, or stay at a shallow depth, as the pure oxygen you are breathing becomes very dangerous at deeper depths. The oxygen once exhaled, is re-processed into a re-breathable form, allowing much longer submersion times.

Lastly, the SEALs make use of a closed circuit mixed gas system. This is very similar to the pure oxygen re-breathing setup, but the oxygen is mixed with air, to maintain a far lower pure oxygen content. This allows the diver to reach greater depth than with a closed circuit Oxygen system safely.

I was actually quite surprised by the fact that the SEALs do not really use anything that is not available to adventure divers in the civilian world. Then again, I guess that due to the fact scuba diving is a dangerous sport, civilians require just as extreme dive gear as a military unit does.

if you want more detailed technical information about US Nay SEALs dive equipment, I suggest you check it out over at How Stuff Works.