Recreational Scuba Deco Diving

[rjack321]

Actually the IANTD adv rec trimix doesn't have a time limit on how much deco you can do, the only limiting factor is that you can only have one deco bottle.
At least that is what we were told when we took the class back in May this year.

And how much time can you do on one bottle?

 

[Degenerate]

And how much time can you do on one bottle?

Half hour is no problem, don't really plan for more deco than that as the amount of backgas becomes an issue in case the deco gas is lost.

 

[AdamSa]

1. Every dive might be a deco dive, max depth is limited by the diulent, max deco time is limited by bailouts. Don't worry about the terminology, just be prepared that some deco might come.
2. ~50/50 mix of shore/boat dives
3. 100% of my dives are in the sea
4. Buddy diving
5. Rebreather with bail out cylinders. A bottom bailout is always carried, a deco bailout is carried if there is a possibility of deco, extra bailouts carried for long planned deco.
6. We plan max depth based on the site and the diluents we carry. We plan max TTS based on bailouts we carry.
7. Reef diving and Wreck diving

 

[Sunn]

1. often
2. boat
3. marine
4. Buddy diving and/or solo diving
5. S80 or equivalent
6. safety stop planned, others not planned, depends on the site (interest, depth, etc), may always happen, adapting
7. sightseeing

 

[Edward3c]

I assisted one of my dive buddies to calculate how much gas he needed for a 100m recreational dive. He ended up with 7 cylinders, plus there were safety divers at 50m. If it had been commercial the dive would have required a recompression chamber on the boat.

They only went to have a look.

 

[Angelo Farina]

I think he wants to know how many have sucked the rust out of a tank with a minute or two of deco left, I wouldn’t hold my breath waiting for that answer.

I think this happened to me just ONCE, at a time where all dives were planned and executed with deco, and only with back gas (the standard tank, at the time, was a 10+10 liters at 200 bar, with reserve valve).
Having the reserve valve, emptying entirely the tank was almost impossible.
The standard planning was to complete the deco without using the reserve...
So in that single dive when I really ended up emptying the tank I did a number of very stupid things...

 

[Divin'Papaw]

@vogt,

Some of the posts in this thread, including this one of yours, are having me wondering if I am thinking of things too narrowly. When I am speaking of a planned deco dive here, I am thinking of a dive that is planned ahead of time using published tables, or maybe using deco-planning software on a laptop/desktop, rather than a dive where someone simply "plans" to allow his/her PDC to go into deco.

When I "plan" a deco dive, I literally use a published table, and a pencil and a calculator and a yellow pad. As mentioned, I ceased doing deco dives quite a while ago. However, I still "plan" them, occasionally, when I get questions from students enrolled in the university scuba course here.

So, at this point, I don't have an answer to your question.

rx7diver

If that was your question I don’t do that ever. When I used to do some technical diving I always planned the dive in deco software (VPlanner, MultiDeco, Baltic) and executed it as a staged deco dive. When doing limited ‘recreational’ deco now I just do the math in my head often times on the fly to make sure I have the gas plus a reserve. I then follow my computer ... Shearwater Perdix AI with Peregrine backup. If it helps my dives these day are typically drift dives from a boat so I can come up at any point when my gas gets too low.

 

[JonG1]

I've done the rust thing once, amazingly on a qualifying dive with a club called Poseidon Nemrod in Spain.

I think I was thirteen maybe.

Over the course of a week we underwent the necessary training to acquire what was then called a brevet.

Aside from ditch and retrieve in 8-10m of water the last dive was to 30m, no bcds then, no spg, 1 reg per diver, single 10's.

As we came back up the instructor signalled the need for a stop, I have no idea for how long. Part way through my reg tightened, and then ceased to deliver gas.

I signalled ooa to the group of decompressing divers (my dad was also in the water but clearly lacked the necessary situational awareness) and a German diver donated his reg and we started buddy breathing.

In the meantime the instructor pulled the reserve (I must have missed this bit of training) and shoved my reg back in and we sat out the dregs of deco, while I waited for the sickening tightening again.

Times have changed!

On the way back our last task involved being thrown back in a mie from shore, fully kitted to swim back in.

At least we passed tho!

 

[J-Vo]

@vogt,

Some of the posts in this thread, including this one of yours, are having me wondering if I am thinking of things too narrowly. When I am speaking of a planned deco dive here, I am thinking of a dive that is planned ahead of time using published tables, or maybe using deco-planning software on a laptop/desktop, rather than a dive where someone simply "plans" to allow his/her PDC to go into deco.

When I "plan" a deco dive, I literally use a published table, and a pencil and a calculator and a yellow pad. As mentioned, I ceased doing deco dives quite a while ago. However, I still "plan" them, occasionally, when I get questions from students enrolled in the university scuba course here.

So, at this point, I don't have an answer to your question.

rx7diver

For planned deco I pre-plan with software and use accelerated deco. I don't consider my Perdix with 3min of deco any different than everyone else doing a 3min safety stop.

Edit: My GF High is currently set to 65. If I where using something like 90/95 the above would not apply.

 

[NothingClever]

This seems like one of those e-mail conversations at work that starts out rather innocently but just drifts off without ever really making a key point or advancing the ball.

Five phrases come to mind:

1) Mission-oriented diving with primary, secondary and tertiary objectives

2) Right training

3) Right equipment

4) Right planning

5) Risk assessment

This toe-dipping, “light deco”, flirtatious approach to decompression seems like it amounts to a casual conversation starter on the boat for the SI (as opposed to a deliberate method to explore).

If I were Murphy, this is the dive I’d love to be on.

Call me a curmudgeon or snobbish but “no thanks”.