Decompression Stop Guidelines - What we have to do if got deco alert?

[joe10540]

Firstly,.do you understand WHY you were given deco and WHY it clears on ascent?

Secondly, do you understand the situations when it WON'T clear on ascent, or may even continue to rise?

(and yes, it WAS decompression... ALL decompression clears on ascent... what differs is the necessary speed of ascent... you can consider stops as simply a method of dictating ascent speed)

The point about no-stop diving is that the minimal training and testing done to get that level of certification has to be tempered and balanced by ensuring you always maintain the option of a direct, timely, ascent to the surface.

You may not consider it emergency decompression if you have enough gas... but that absolutely ignores any unforeseen contingency that might arise.

Contingencies that you haven't planned or prepared to deal with whenever immediately surfacing ceases to be your safeguard option.

A little experience can be a bad thing. Enough to think you know better, but not enough to have encountered the inevitable issues that show you don't...

Fair enough. Yes I understand why I was showing a deco obligation on that particular dive and I also understand why it cleared on my ascent. Also I was on my first dive of the day in doubles with EAN32 onboard as were my two dive buddies so I was equipped to handle just about anything that could have arisen. In my case I forgot to reset my settings after getting my battery replaced so my computer was on the most conservative setting instead of the next to most aggressive setting. After adjusting on my SI I had no issues with my computer conflicting with my dive planner. My point was though that someone who doesn't understand why that happens could get into a real obligation by just assuming oh it will clear as I go up just like it has all day not realizing that the slow compartments have started to catch up to the fast compartments and are becoming the controlling ones.

 

[The Chairman]

Here's the thing. All dives are decompression dives. It's why we have limits on rates of ascents that change from deep to shallow. People put a lot of emphasis on 'no stop' diving and then they throw in a safety stop, or as I call it: voluntary or precautionary decompression stop. A stop is a stop. I will confess that I teach and stress gas planning, checking your and your buddy's gas supply, knowing your SAC and how to determine how much gas you need from OW. Hell, it's a required skill for NASE, so I have to teach it. I certainly don't feel a need to scare people into taking another class to learn decompression for such incidental deco. In fact, I certainly find it reasonable for a diver to venture into deco by five to ten minutes if they have those lessons about gas planning firmly in mind.

 

[lermontov]

Fair enough. Yes I understand why I was showing a deco obligation on that particular dive and I also understand why it cleared on my ascent. Also I was on my first dive of the day in doubles with EAN32 onboard as were my two dive buddies so I was equipped to handle just about anything that could have arisen. In my case I forgot to reset my settings after getting my battery replaced so my computer was on the most conservative setting instead of the next to most aggressive setting. After adjusting on my SI I had no issues with my computer conflicting with my dive planner. My point was though that someone who doesn't understand why that happens could get into a real obligation by just assuming oh it will clear as I go up just like it has all day not realizing that the slow compartments have started to catch up to the fast compartments and are becoming the controlling ones.

it could have been worse - if your DC had reset after battery change than I'm assuming it would also be reset to 21% and I see you were diving 32%

In another in another post you said 'I am not a decompression diver by any means," please down think Im picking on you but I suggest you become one for your own safety- you'll really enjoy it and its a doorway into another aspect of diving

 

[joe10540]

it could have been worse - if your DC had reset after battery change than I'm assuming it would also be reset to 21% and I see you were diving 32%

In another in another post you said 'I am not a decompression diver by any means," please down think Im picking on you but I suggest you become one for your own safety- you'll really enjoy it and its a doorway into another aspect of diving

That class is on the books for later this summer. I plan fully to get AN/DP class sooner than later. Still I understand the basic principles associated with decompression practices (still I don't venture into that realm yet too many what ifs) setting my PO2 is pre dive every dive but the conservativeness of the computer it's set it and forget it until the next battery change in 3 years.

Also I do pre dive planning on a dive planner and knew before getting in the water what kind of times I could expect before I hit any virtual overhead. I never just fly the computer.

 

[dmaziuk]

I was diving with some friends and my computer was beeping away telling me I had over 20 minutes of mandatory deco and their computers hadn't even cracked NDL yet. Sure enough by 40 feet I was back in the black on my NDL clock.

But that's the point, as I understand it: PADI OW cert is for non-stop dives, as in "you can proceed directly to the surface at any point in the dive". At the point when you had 20 minutes of deco you could not (fine print aside) proceed directly to the surface. That's the point where you're diving beyond your cert, the sky is falling and it's all an OMG YOUR GONNA DIE!!! emergency. The fact that you were not in that state a few minutes later in the dive is irrelevant.

 

[joe10540]

But that's the point, as I understand it: PADI OW cert is for non-stop dives, as in "you can proceed directly to the surface at any point in the dive". At the point when you had 20 minutes of deco you could not (fine print aside) proceed directly to the surface. That's the point where you're diving beyond your cert, the sky is falling and it's all an OMG YOUR GONNA DIE!!! emergency. The fact that you were not in that state a few minutes later in the dive is irrelevant.

Except for the fact that I WAS able to make a controlled ascent directly to the surface without stopping (aside from a 3 minute safety stop) and I knew that I could based on three things 1) I planned the dive before getting in the water 2) past experience with the depth and time I knew that I could make a direct ascent without issue 3) both of my dive buddies computers showed 7 and 13 minutes of NDL time still available. It was my error for not changing the conservativeness of the computer back to the second most liberal setting after getting it back from battery replacement. I know it isn't really a safe practice to just disregard what your computer is telling you and certainly not advisable for someone who doesn't know why it is saying what it is saying. I also know that in that situation I had enough resources and support from both dive buddies to handle any situation that could have arose in the conditions we were diving.

 

[dmaziuk]

Except for the fact that ... I could based on three things ...

Yes, that what I meant by fine print aside. But I can see the problem with trying to teach all that to new OW students in a couple of classroom sessions. Much easier to stick to the letter of the law and say this is NDL, never exceed it ever or else.

 

[Hatul]

I dive with a Galileo Sol and a few times on deep dives I've come close to deco and on the initial ascent the computer went into deco. In every case the deco eventually cleared on further ascent and I could continue with a non deco dive.

While a deco obligation does increase the risk, you should have enough reserve gas anyway to complete a small unplanned deco stop.

 

[jseyfert3]

IDCBali was last seen: Wednesday at 8:47 PM

In other words, he logged out two minutes after NetDoc made the first post and hasn't been back to the site since.

 

[RainPilot]

Just because the host had to leave early doesn't mean the party's over...

Some of the most interesting discussions ever on this board have resulted from random drive-by postings.