What to do if . . .

[lowwall]

While there is an ommitted decompression procedure that does work, too many things have already gone wrong on this dive.

Get on the boat and breathe O2 (or the hottest mix available if there is no O2).

Exactly. By apparently using PADI NDL tables to "plan" deco dives, the OP has already shown a willingess to take info and push it far beyond where it was meant to go. Any attempt to add advanced techniques like IWR to this makes it all too easy for a solvable problem to spiral completely out of control.

Maybe we could take any advanced discussion over to the Ask Dr. Deco forum?

 

[Charlie99]

While there is an ommitted decompression procedure that does work, too many things have already gone wrong on this dive.

Agreed. In a controlled situation, omitted decompression procedure (which differs from In Water Recompression in whether or not the diver has DCS symptoms) is an appropriate method of reducing DCS risk.

OTOH, if things are already that screwed up, then the risks of screwing up and doing something stupid like going back down with someone's used, nearly empty tank is a pretty signficant risk. An incident a few years back in So. Cal had a diver with an empty tank grabbing a tank and reg, hugging it as she descend back down by herself to do stops. IIRC, the final result was the spare tank floating back up to the surface, and the diver dead.

One has to balance the risk of drowning vs. DCS. If it's an out-of-control, confused situation, staying on the boat is the best course of action.

 

[TSandM]

Whoa . . . the OP didn't talk about planning decompression diving, or say anything about Navy Tables. The OP just asked the question about what to do if you end up more than 8 minutes over your NDLS and don't have enough gas to do the required deco. There was no planning implied at all.

 

[Wijbrandus]

If I were in that situation, I'd do the deco to the limit of my gas, and my buddy's if he/she's got extra. Then I'd get on the boat, get on O2, and pray there are no symptoms. If there are, I hope a chopper is available. If there are no symptoms, I'd be on the phone with DAN as soon as a connection could be established.

When it's all done, I'd be doing a lot of explaining to my wife about how I managed to screw the pooch that badly, and why she should allow me to continue diving after such a disaster. In the end, I'd have to ask myself that very same question, since at my level of training and experience I should never be close to being in that position.

Based on the OP's public profile, he's got at most 500 dives over a dive career of 40 years, with an OW level certification. I hope misfortune never takes him to that level of trouble.

It's a good question, but if it happens to someone, they've already had so many things go wrong...

 

[MikeFerrara]

Whoa . . . the OP didn't talk about planning decompression diving, or say anything about Navy Tables. The OP just asked the question about what to do if you end up more than 8 minutes over your NDLS and don't have enough gas to do the required deco. There was no planning implied at all.

Yep, no planning at all.

 

[TheRedHead]

It seems to me that slinging the tank he left on the boat would be a better solution than omitting the stop, retrieving it and descending again.

 

[Thalassamania]

Better still:

1) Don't overstay your welcome to begin with.

2) Always leave some gas at 30.

3) Get another book, somewhat more revent, somewhat more advanced to review before the season.

4) In fact that would be a good rule for us all ... at least one new book before the start of each diving season.

New thead on that topic coming up: A Book for New Seasons

 

[all4scuba05]

I guess I qualify as one of those “older divers.” I still dive Navy tables. Why – because they are much better tested than other set of tables and they are more suited to the type of diving that I do.

Here is the Navy procedure for Omitted Decompression:

1) Surface at normal rate.

2) If asymptomatic and capable of returning to the water within 5 min. of surfacing then return to the depth of the omitted for 1.5 time the initially required decompression.

3) It the diver can not return to the water within 5 min, then a min. of 60 min. of oxygen is called for.

4) If asymptomatic after 60 mins of Oxygen the diver should be observed for 12 hours (no diving, of course).

5) If symptomatic, transport on oxygen to nearest medical facility.

6) If asymptomatic and unable to return to the water for omitted decompression, and a chamber is within 1 hour, transport to chamber.

You will find that the 15 at 15 is actually a Navy recomendation for a diver who has exceeded the Navy no-D limits and does not have access to a set of in-water tables.

When I plan a no-D dive I still check out the decompression that would be required if I go deeper or stay longer and and write that out on a slate (I went over that procedure in a another thread). I carry a set of in-water tables and since I always make a 3 min stop at 1/2 my max depth, I can check them there.

I was wondering when someone was going to put that reply up.

There are those that would rather stay out of the water and pray they don't take a hit. Then there are others who will drop down again for the Deco stop and stand a lesser chance of getting "hit" after all they are decompressing.
So the original poster would have to make up his mind and decide which group he wants to belong to. The group that skips the deco stop and hope sucking on O2 is good enough, or the group that decides to grab another bottle and go do the mandatory deco stop plus a few more minutes of it.

 

[lowwall]

...The group that skips the deco stop and hope sucking on O2 is good enough, or the group that decides to grab another bottle and go do the mandatory deco stop plus a few more minutes of it.

Another way to phrase this... The group that skips the deco stop and hope sucking on O2 is good enough, or the group that decides to grab another bottle and hope they don't screw this up (like they've already screwed up so much on this dive) and end up in much worse shape.

In reality, a lot of this depends on the conditions and the physical and mental sharpness of the diver involved. If everything looks good, I'd probably go back under. But how likely is this problem to occur if everything looks good?

In other words, if you are in this predicament because, while you never lost your cool, it took you a while to fight off the giant squid with your whistle and safety sausage (the first thing the giant squid does of course is grab your primary and back up knives), I'm pretty sure you can handle an omitted decompression procedure. OTOH, if you are in this predicament because you were distracted on the bottom by the pretty fishies and then started to hyperventilate once you saw how long you'd been down...

 

[Thalassamania]

Omitted decompression and in-water recompression are two different things and two different issues.