With normal recreational scuba equipment and breathing normal air we are limited in the depth we can go typically 60m is our maximum due to oxygen toxicity and nitrogen narcosis. To overcome these depths we require special scuba diving equipment, proper training and the correct mixes of gases that we will breathe.
Beyond 40m’s scuba diving turns from a recreational sport to technical diving, and it is very easy for technical divers to approach 200m with closed circuit rebreathers. As we said oxygen toxicity occurs, technical divers overcome this by mixing their gases. Usually mixing helium and oxygen will eliminate the nitrogen narcosis.
Commercial divers can operate to depths of 200m and typically work for 6 hours a day and stay down for a month at a time. This way they do not waste time decompressing every time they come up. To be able to stay down for a month they live in decompression chambers while they are not diving. The compression chambers can be located on the ship or even next the dive location on the sea bed.
The next step beyond 200m is with Newt Suits and these suits effectively bring down the environment with them. With these suits divers can easily reach 300m. The idea behind these Newt suits is they maintain one atmosphere of pressure; this is basically what we breathe on the surface. The advantages are they eliminate most of the dangers related with decompression sickness and nitrogen narcosis. Currently the likes of the US Navy use their own version of a Newt Suit.
