Quote: (Originally Posted by
Lancer4545)
they boosted a little O2 on top of a full cylinder of He and then topped off Dil tanks as required. they were diving 40-60mins bottom, 200 mins total run max
We were doing similar bottom times to these and were coming up with total run time nearly an hour longer. Plug their mix in and the end result is over another hour deco longer.
Hi Lance,
It is not possible actually to plan a dive at 75m for a little more than 200 mins under any circumstances. (Given there is only helium as inert gas in your loop, i.e Heliox).
I played a little bit with a self-developed deco software and here is what I found:
It would be possible to make this dive if the following conditions are met. Unfortunatelly these are lying outsite the commonly acceptable level of risk for the prudent diver:
- Plan the dive with a descent rate of 10 mpm (You are at 75m at minute 8).
- Stay at the bottom until 60th minute run time (stay down for 52 minutes).
- Ascent rate at 10 mpm also.
- Maintain PPO2 at 1.8 and switch to 1.6 at 8 meters (Would you accept this as a calculated risk??).
You will end up with something like 205-210 minutes. And that is Modified Buhlmann (no GFs). For Helium I would like to add some GFs though. Therefore unless if you are a super trooper diver and ready to accept the risk of getting your brain cells oxidised and rusted you wouldn't be able to do this dive in 3,5 hours.
Cheers,
Sotos