Deep Diving 108 feet w/ a single AL 80 (Air.) No redundancy.

[broncobowsher]

Went back to my logs from Blackbeard's in the Bahamas.
118' for 34 minute
121' for 34 minute
and a few more over 100' with 40+ minute run times.
All done on a singe AL80

 

[Centrals]

11L tank for a 30m non deco dive is plentiful if you have relatively good gas consumption.
I won't even blink an eye if someone suggesting to me!

 

[formernuke]

Hello. I was thinking back over the years. I worked for a Dive shop years ago as a Divemaster.
We did our deep dives on the Chester Poling off Gloucester, Mass. for the P.A.D.I. Advanced Open Water Course.
At high tide the the wreck sits in 108fsw. It always amazed me that people would do this dive "Normally." on single aluminum 80's without any type of redundancy.
I always thought it was insane???? Divers would come back on board with extremely low pressure readings on their gauges. Too me, it left no room for error, or any type of contingency whatsoever. At that time, I was diving with an Aluminum 100 cubic 3300 P.S.I. (Air.) with a 30 cubic pony bottle.(Air.)
20 years ago the shop did not have "Nitrox." (This is not an enriched air scenario.)
Staying within N.D.L.......I don't care how long you've been diving, or if, your'e the best breather on the planet your max bottom time is approximately 18 to 20 minutes, at 100fsw, not including the 3 min Safety stop.
So, I was curious? The question is: Would you personally make this dive, staying within N.D.L. on air........No redundancy?
Cheers.

Now, hell no.....

With that said the first time i went deep was 103 with a AL 80.... being young and dumb as I was back then.

 

[Seaweed Doc]

I've gone to 140' on an 80. I'd do it again for fun. But with students, as an instructor, I want more air just in case.

 

[ChuckP]

If an aluminum 80 was all that's to be had then that's what you dive - NDL and gas volume aside no matter the tank size, it's a recreational dive...... I'd want you to be aware and have a plan for a low pressure hose failure but we should always be aware and have a plan for that...

I wouldn't even say there's "more room for error" with a bigger tank - every little bit counts maybe but at 1000psi in an 80 verses a hp120, you got 9cf more gas.

Is it worth diving that with an 80? I'd be looking for a set of doubles personally.

 

[Celt]

With good vis, no risk of fouling, no responsibility, no deco and a clear path to the surface I wouldn’t have a problem with it. But there’s very few wreck dives at 108 feet in my area that would fit that plan.

 

[Boston Breakwater]

I had to go back to July 2006 in my logbook to find my two POLING dives and see what gear I had.
It was Cape Ann Divers, Faber steel 100s pressed up to 3200 with air. Had to wear an unfamiliar BC because buddy’s had some type of failure while we were still on the boat Only spare one was the deckhand’s, too small to fit him. So we tried mine and it was just barely big enough to fit him. So I got the deckhand’s BC, which was just barely big enough to fit me.
Went to 94 feet to see where ship’s bottom was, to see how it came apart in tension as she split in two in awful winter storm. I was still getting used to the bc, I remember the inflator and dump valve felt kind of vague, but they did work. And buddy’s tank strap (meaning my tank strap) came loose, I had to refasten it.
COLD despite 3rd of July, air 75, water 62 surface and 45 at depth. Great dive but only 26 minutes. Second dive less deep and I was cold, and almost grateful when computer ordered me up. I think an 80 would’ve been too small.
This is a good memory. I remember when Poling sank in 1977, I was in the Coast Guard in Boston and knew a couple of the rescuers. They risked their lives, it was a really bad winter storm.
Anyway that’s my story. I don’t think an AL80 would’ve been quite safe enough.

Hello. Very nice account.
Thanks.
Cheers.

 

[Searcaigh]

Staying within N.D.L.......I don't care how long you've been diving, or if, your'e the best breather on the planet your max bottom time is approximately 18 to 20 minutes, at 100fsw, not including the 3 min Safety stop.
So, I was curious? The question is: Would you personally make this dive, staying within N.D.L. on air........No redundancy?

At the depth you mentioned 108 ft which is approximately 33m I probably would not do this on air today, although I have done deeper dives on an AL80 years ago but with very short time at that depth in the Red Sea off Jeddah when I lived in Saudi back in the 80s/90s

Today I rarely dive air unless I have shallow dives planned (less than 18m), and I always carry a pony / stage with EAN50.

We have several dive sites that at 30m and plenty divers do this on air using a single AL80, whereas I prefer EAN34 for that additional bottom time (square profile dive) and will switch to EAN50 at 21m on ascent. I've become more realistic about my own mortality as I've grown older. I usually surface with 80-90 bar in my AL80 and use around 40-50 bar in the AL30 pony.

 

[J-Vo]

A dive like that really depends on your SAC rate and (if you have one) your buddy's.

If your (and/or your buddy) are doing a normal NDL dive and are coming up with less than 1500 in your Alum 80 then you are pushing it.

Ok, so now we are saying NDL divers need more contingency than cave divers? Anyone can be as cautious is they choose for themselves, but this is a bit over the top. Start the ascent at 1500, sure depending on your SAC that may be prudent. I would probably wait for about 1000, but would likely hit NDL first. All that said, I haven't dove to any significant depth with a single in years.

 

[Jonn]

I wouldn’t blink at this sort of dive either. Any little problem at depth will become a big problem pretty fast, the margin isn’t really there, and a buddy isn’t giving you much more either and you might be safer alone. I would feel better about it with a pony and / or a steel 100 but I’ve done it before and will do it again if the reward seems worth the risk.