Just to add a little clarification here, I am not an advocate of 300 foot dives on Open Circuit Trimix, unless they are something along the lines of touchdown divers.
In 1994, we dove on Lusitania at about 300' using OC. To tell the truth I felt we were near the limit of OC for working wreck dives involving exploration and photography, primarliy because we were so ill equipped to manage emergencies like entangllement, getting lost, equipment malfuncitons, etc. We had to rely on our experience to try to avoid the pitfalls.
At the time, rebreathers for the masses were not available and we had no other choice, but we knew we were near the edge. If you scare yourself in 300' on Trimix, you will undoubtredly have a gas management issue as your bottom mix disappears. Now you have two problems? Today, I think the rebreather makes a better means for diving to 300' or even greater depths because the units themselves have evolved so well.
Rebreather technology enables the diver to use a constant PPO2 and decompresses in a nice, easy curved profile, as opposed to the jagged saw tooth profile from OC Trimix with multiple gas switches. This is especially true if the diver follows a ceiling, instead of stop depths.
THis would seem to be far more friendly, biologically speaking. Rebreathers also enable the diver to use heliox, as opposed to Trimix, which is far too expensive on OC. I am a big, big fan of Helium, and credit it for keeping me in deep water. Virtually everyone I know who has gotten bent on a deep dive, has been bent on Nitrogen, or at least the N2 element of Trimix?
Then again, with rebreathers comes increased responsibility, which we had anyway with deeper depths?
This is just what has worked for me.
Cheers
JC
soo sorry but if i didnt I'm sure Ohm would have.
