Deep Diving on Air

[dumpsterDiver]

Here's the difference.

In the worst case scenario, a diver at 60 feet with no overhead environment diving within NDLs can go straight to the surface with no serious threat of a problem.
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You crack me up with that one...Worst possible case is the diver swims staight up from 60 feet with no air!!! LOL.. I've had a lot worse things happen to me at 60 feet...

 

[VooDooGasMan]

Dr Bill has said the same thing for 3 to 4 years and not changed his thoughts on it, I agree with Akimbo and dump. And dump has it with others too narced out of it just over 100' are not going to do well deeper, not to say they can work up to 140' so not to miss out on dives while travel diving.

The less nitrogen you take in on the way down the less narcosis affects me, If I have to do any kind of exertion I will be more narced. That is why I Have not Done so many Deep Air Dives until this past summer. In the great lakes you hook to a wreck and your screamin on your way down the line, as the wreck appears ya hit the elavator button to slow so not to crash on deck, maintain buoyancy and take a gentle cruise then come back and ascend up the line. Then let the line out and watch depth finder, drop a shot line, back then it was a hard lead weight belt. Do a second dive on that part of the wreck. The bet was could you ever find the same spot. Narcosis was always less on second dive and was this summer also, this summer was even easier as I just descended got in sight of bottom and flew for miles, stopped to gather seafood and check out sealife was all it was about.

The thread cave diver closed a bit back had some good info from members, hopefully we can re evaluate again with more discussions. I have been Diving with a Great diver from the past, he still dives a good couple hundred dives a year, and is doing his life story so all the ones in it can enjoy before they die, were Talkin almost 40 years of diving and more detailed pics and Info I have ever seen in my Life.

His link is JanKocian's Photos give him a comment if ya get time.
go to the one that say's Down the memory lane.
you will learn more about the south pacific there then any where else in the world.

So I guess I only give my experience on Deep Air Diving and Bounce Diving cause after so many years I wont be here either, of course I have not a dive log at all except some pics on computer, and about fifty photo albums from film.

 

[DaleC]

Here's the difference.

In the worst case scenario, a diver at 60 feet with no overhead environment diving within NDLs can go straight to the surface with no serious threat of a problem.

A coldwater diver doing a recreational dive, descending at 60' on a wall (Kelvin Grove BC) turns their head and floods their hood which produces a case of vertigo...

A coldwater diver with thick exposure protection, pushing up against the NDL's after returning from a deep shore dive (Porteau Cove BC) loses their weightbelt at 60'...

A coldwater diver on a current sensitive dive (Keystone WA) has a major drysuit flood at 60' (well 45' anyways). The water temp is 42 degrees F...

A coldwater diver returning from a long, shallow shore dive has a freeflow at 60' just as a tug with a log boom passes overhead (Bedwell Bay BC)...

no problem...

 

[Akimbo]

From the perspective of discussing the OP's dive, how would you define "deep air dives" and "close succession"?...

It is hard to put numbers on depth, quantity, and interval. I usually start to notice improvement in as little as 5 dives. Performance often improves after weeks of daily exposure at 160-200', both in dexterity and problem solving. Perceptions of divers and supervisors usually agree. Of course there are other factors but the general belief is narcosis tolerance improves. To make giving you a formula even harder, sometimes everyone has a bad day which we prefer to blame on narcosis rather than screwing up.

…If two buddies with better than average SAC dive larger than 80 cf tanks, does that constitute redundancy? ...

I will leave that for others to debate since I don’t consider a buddy a reliable form of backup unless you have a team tasked with protecting you in a one-way support-the-working diver scenario.

…If taking a couple pictures is the only planned "work", could the recreational "bar" be set lower than Scientific Diving's "bar", as is done at every other depth from 132' up?

I think not having an objective can put some divers more at risk for narcosis. I don’t think it adds to panic-inducing paranoia in most divers, but lack of concentration gives “stupid” free rein. I have learned that my best deep air performance includes a lot of mental rehearsals and what-ifs before getting wet.

 

[shoredivr]

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A coldwater diver returning from a long, shallow shore dive has a freeflow at 60' just as a tug with a log boom passes overhead (Bedwell Bay BC)...

Puts quite a hard ceiling on the old recreational dive, no?

Sorta like the St Clair River with freighters going by.

 

[Centrals]

If two buddies with better than average SAC dive larger than 80 cf tanks, does that constitute redundancy?

A redundancy for a trained tec diver is the life saving equipment that he/she carries. And of course in the overhead environment than he might need his buddy contribution if there is a gas failure. However, there would be a pre-calculated "turn pressure" instead of 50/70 bar.

 

[Rhone Man]

You crack me up with that one...Worst possible case is the diver swims staight up from 60 feet with no air!!! LOL.. I've had a lot worse things happen to me at 60 feet...

Anytime someone posts the words "the worst possible case", that is just throwing down a gauntlet to the imagination of the members of SB...

 

[VooDooGasMan]

Dale it reads like you were present on these dives and I thought wow you have better be a good rescue diver, and the thought that keystone has 42F was a bit cold for our waters, maybe your metric was off. I,m thinking 48F would be the coldest but 50F normally and a range of 52F to 58F for the most part.

I will have to look at temp as my buddy was really cold today, yet we dive damn near everyday and I never look at temp. I'm so warm now I just started going dry for the winter, never got that cold in a wet suit all summer.

 

[MXGratefulDiver]

I've seen 42F at Keystone ... in late February ... but you gotta get a bit away from the jetty to find 60 feet of water ...

Temperature readings on dive computers are notoriously inaccurate, but my X1 is reading about 50F in most parts of Puget Sound right now ... a bit colder than that in Hood Canal ...

... Bob (Grateful Diver)

 

[DaleC]

I had to adjust depth up for Keystone but the temps are there for winter diving. Bob, 50F! It's still summer conditions out there. Tell someone in Florida that and they just shake their heads...
The point was that there are plenty of bad scenarios that someone can find themselves in rec diving in 60' of water and I thought I'd add places and scenarios that I have actually seen/been so someone couldn't say that it was a theoretical point.

The tug overhead was a kicker for sure and illustrates that boat traffic is one unintended overhead that recreational divers could very easily encounter.