:) Fun question : How deep have you gone on single tank ? What's your record ?

[AfterDark]

Until you have or are experienced , the "don't dive deeper than your tanK" is a good rule of thumb

Another rule of thumb for recreational depths for PSI time to start up / reserve air (rock bottom) that I use is from Lamont's useful post on it ... for my HP100 tank it would be - Depth , add a 0 to it , + 400 psi ... IE at 100ft +0 +400 = 1400psi to start ascent ... an AL80 would be +500psi

and I think we should not post in Basic Scuba about a depth you have dived on a single tank without mentioning your experience level
... 109ft witha 100cf tank on the wreck Baja California , with AOW and Rescue , and several dives to 90 - 100

Do you mean now our when it was done? Personally the experience level I have now... no way would I repeat that deepest dive I posted at least not the way I did it. I know better now, I was lucky there was nothing to see down there so I didn't get distracted. The max set needle on my depth gauge hit 170fsw I turned around and started back up. I could have easily run out of air if I hadn't.

 

[Dirty-Dog]

It's probably (especially in Basic Scuba) important to mention tank size and maybe a bit of the dive profile, and whether or not the depth was planned.

Deepest dive on an AL80 - 111 feet in Punta Sur. I don't have an exact dive profile for this dive, because my Suunto had failed and I was diving my Aeris XR-1NX instead. We were below 100 feet for about 12 min total (no deco incurred), and then came up to the top of the wall, turning the dive at 750 and back on the boat at 500. Total dive time was 29 min.

Earlier in this thread, I posted a summary of the dive profile for our deepest dive ever; planned 155 feet in Cenote Angelita, on 120cf steels. A single tank dive, yes, but that extra 40cf makes a world of difference.

 

[Sat Diver]

By single tank , I meant not with Tech mixes like Trimix.

Why is trimix considered a tech mix ? It is no more "tech" than nitrox, just a lot safer for the depths you are talking about. Control ppO2 and narcosis. It's a no brainer in my opinion.

 

[D_B]

because it's not likely to be used by/in "Basic Scuba" ?

 

[Tortuga68]

You don't come across many recreational divers with trimix certification

 

[Sat Diver]

You don't come across many recreational divers with trimix certification

Ok. But going to those depths on air is pushing the limit of safety with narcosis. Nitrox at those depths offers you marginal benefits on the narcosis front and you up your ppO2 to marginally dangerous levels.
Honestly training for trimix certification is very easy, and my point is that if you took away the "tech" tag from trimix, maybe more divers would use it for these dive profiles and have a way safer experience.
Diving trimix does not mean you have to do some crazy depth. Just replace some of the nitrogen with helium. You can still dive within NDL limits with trimix.

 

[Mossman]

Besides the cost of helium (and the cost of training to use it), how available is it except to local divers with access to local tech facilities? In some locales it's difficult or expensive enough to obtain nitrox for a dive let alone helium.

 

[Tortuga68]

Ok. But going to those depths on air is pushing the limit of safety with narcosis. Nitrox at those depths offers you marginal benefits on the narcosis front and you up your ppO2 to marginally dangerous levels

I would say nitrox offers you no benefit on the narcosis front since oxygen can be just as narcotic as nitrogen

I take your point about using trimix, but I can't see it becoming the gas of choice for recreational divers who are doing ~40m bounce dives - which is basically what we're talking about here

 

[Thalassamania]

Bounce to 190 in warm clear water to take photographs of a descending submersible.

 

[sassyalice]

I hit 149' on a Cozumel wall. And in Cocos I was routinely at 130' and holding for pics