Well actually thats slightly incorrect I use pure O2 on my re-breather and high O2 content breathing mixes (Nitrox and 56%) for decompression gasses for use at low depth stops. But as a rule, most diving is done on breathing gas mix of 21% O2 and 79% Nitrogen, commonly known as *Air* with a max depth of 50 mtrs as Oxygen gets toxic under pressure. Other mixes of gasses i use are: Normoxic is 21% O2 with up to 20% Helium topped of with 59% Nitrogen. Max depth with a PPO2 of 1.4 is approx 50 mtrs but helps reduce Nitrogen Narcosis (the narks) which make you feel *at best DRUNK* at worse DEAD! TriMix, can be as low as 8% O2, up to 58% Helium and the rest Nitrogen. Working on a PPO2 of 1.4 can get you to serious depths over 100mtrs. We use pure O2 on the rebreather as that fires O2 in short bursts to make up for the 4% we breathe and use per lung full, so every 3-8 breaths, the O2 is replaced in the loop by the system. Im my diving i often use a Diluent mix of 10% O2 to get me to 80-100 Mtrs. Diluent is just a fancy name for the breathing gas, but i only use very small amounts as i am breathing scrubbed air much the same as an astronaut does, infact it is pretty much the same system as used in space However i carry 2 x 11 ltr cylinders of breathing gas as a bailout, just in case the system goes tits up. Like wearing protective clothes, its an insurance and back up if anything goes wrong. But as many have said, its your choice to do whatever you wish. People say im crazy for risking my life every weekend im out diving. Its all about risk mitigation and faith in the Meg (ISC Megladon) and the equipment i use. I have seem many things that 99% of the population will never see or experience. I love my hobbies but i wouldnt dive without adequate gas, equipment or system redundancy. But each to their own
So what's with the no bubbles application? We used rebreathers in the North Sea but that was to give us time to escape an upturned helicopter.... After we'd all been smashed to pieces in a crash
Ah yeah, those re-breathers are just a bag did my survival courses in the Marines back in the day, same as Sub escape kit....basic to say the least, and a little hit and miss. The no bubbles comes from the fact its a loop, so the gas you breathe goes round, through the CO2 scrubber, into the counter lungs and back to the diver. In essence its a no loss system. Well as low loss as possible. You loose gas as you start to ascend from depth (Daltons and Boyles laws at work) Rebreathers get you very close to marine life, sharks in particular as they create no noise (no bubbles from the DV)
Cool... It's all moved on a bit since I was last scuba diving in the Red Sea when I was working in Saudi (1991) That rig looks mega buoyant. Do you tie a couple of blacksmiths anvils to your waist?
Nope, its neutral so i only use weight when in the sea, and only 2 Kilo. In a Dry Suit im using 6 K. The balance is really nice in the water, the 2 x 3ltr cyls are Steel 300 bar ones so they add a bit of extra weight to the rig. Ally 3 ltr ones make it a bit light and i need another 2 kilo, so max i take is 8 kilo, in a shorty wetsuit i dont take any even in the sea, in a semidry ill add 2 kilo. Using 2 x 300 bar cylinders gives me a max dive time of 4.5 hours, the limitation is the scrubber life, not gas. Oh and decompression stops as well of course....loooonnnnggggg boring deco stops at 9mtrs. Thank god for trapeze lines and Ipads in cases
I had a very high speed head on in full leathers, right by a hospital.... I thought I was sort of ok until the Doc undid the zip and started barking orders for various teams to be assembled for a good days work. I think his reaction scared me as much as the crash. Always worn the full garb, but admit to just paddock boots, tough jeans and a light armoured jacket to nip to fill up with fuel; a 3/4 mile return trip. My serious off (3 years ago) was at the end of our cul de sac!!
