first deco dive

[BDSC]

I was diving a wreck in pensacola Sunday and my computer was inching toward deco mode while I still had plenty of air(1500psi). I let 0min come and go deciding to test out the deco mode. I started my ascent and the deco stop was displayed at 10' for 2 min. A little anti-climatic since my regular safety stop is more conservative.

Anyway, I was hoping for some feedback from you more experienced divers on whether this would be considered wreckless behavior or is deco diving really just part of the sport if done conscientiosly.

I don't see the situation, as you have described, as being reckless at all. You had plenty of air and were well aware that your computer was about to go into the deco mode. It wasn't like you weren't paying attention and the situation crept up on you. The last time I dove off our coast over the weekend all 4 of my dives went into deco for a few minutes which happens a lot of the coast of NC because of the depths. While you did not say in your post, I will assume you were with a buddy and not solo diving. So as long as both you and your buddy were cool with it, I don't see what you did as being that big of a deal. Probably a good learning experience really.

 

[ZenDiver.3D]

I don't see the situation, as you have described, as being reckless at all. You had plenty of air and were well aware that your computer was about to go into the deco mode. It wasn't like you weren't paying attention and the situation crept up on you. The last time I dove off our coast over the weekend all 4 of my dives went into deco for a few minutes which happens a lot of the coast of NC because of the depths. While you did not say in your post, I will assume you were with a buddy and not solo diving. So as long as both you and your buddy were cool with it, I don't see what you did as being that big of a deal. Probably a good learning experience really.

I am not surprised that you don't see a problem with it. You dove a weekend and ALL 4 of your dives went into deco? You ran yourself over every time? That does Not happen a lot by responsible divers. That happens for reckless, careless divers.
It has nothing to do with the depth off the coast. I urge you to step back and really examine your dive practices. I would not want to see you in the accidents forum, but if you continue to dive this way, we will.

 

[hg frogman]

By "mild deco" I mean less than 15 minutes of required total deco time, assuming one uses the same gas (air or nitrox 32) throughout the dive (stops included) and respects the maximum depth for this gas. An adequately experienced buddy team with low SACs can safely do that kind of dives with single tanks of adequate size.

This kind of diving is no sin (despite what some agencies use or used to say) and no rocket science (despite what some tech instructors or tech divers, prone to overkill, may say). But a recreational diver needs some additional learning and training, otherwise he/she may get badly injured.

For example, deco diving (even "mild") usually means 2 dives maximum per day (and quite often only 1 dive per day, it depends upon the severity of the dive) with a surface interval MUCH longer than 1 hour.

And there are some other things to know (e.g. understanding deco dive tables) that I won't mention or detail here. One cannot learn to dive by Internet only.

All decent dive computers that I know (at least Uwatec and Suunto) give all the information needed for mild deco diving with one gas (air or Nitrox 32, with no other gas for deco). And this is reliable, proven, information. These dive computers are routinely used for such mild deco diving by most French divers, including me.

But, because off-gassing is slower than on-gassing, it's safer to pad what computers say when it comes to surface intervals. Also it's a good practice to pad (add extra minutes) the shallower stops that your computer tells you to do. Bottom line : it's better to know what you are doing, even if you use a dive computer. A good course about deco will help for this.

A good Surface Air Consumption (SAC) and a proper gas (e.g. rule of thirds) and dive (depth and time) PLANNING are paramount because deco stops durations increase sort of exponentially (5 extra minutes of bottom time may represent 20 extra minutes of deco stops or even more) and if you don't take care you have to dramatically increase the duration of your stay underwater, thus risking OOA.

Also you need proper buoyancy control to accurately maintain your depth, notably (but not only) during the stops, and to master your speed of ascent. Proper weighting and buoyancy will reduce your SAC. Better reduce your SAC than breathe like a hoover because of all the heavy stuff you are carrying underwater.

Introductory courses for deco diving are CMAS **, or TDI Decompression Procedures, for example. In my opinion you'd better join such a course before doing deco dives. The problem with some agencies is that they use very heavy setups (twinset + stages, etc) for mild deco diving, as if there was nothing, regarding gear configurations, between no-deco diving and advanced Trimix.

 

[MXGratefulDiver]

39 min of deco.....how can this happen????
First of all you need to have a basic idea of you deep and times even without computer.
He must have seen the computer counting down 5,4,3,2,1,0 and that up again till 39????
39 min deco must be a long time at great deep

No one can be that silly, or??

Er ... sure they can ... people "talk" themselves into bad situations all the time. Been there myself a time or two.

I recall my first trip to Catalina Island ... my third dive at Casino Point I ended up with a 29-minute deco obligation, because I'd been diving air (nitrox is damn hard to come by on Catalina Island for some reason) and the park is so fascinating. I knew I was going into deco ... I was just taken by surprise at how quickly it racked up before I could get shallow enough to do something about it.

Fortunately, I was using a 130 ... and there's plenty to look at in 20 feet of water at the dive park.

But I can easily see it happening to someone who isn't paying attention to their NDL and is diving deep on air ... it's the sort of mistake you make, hopefully, only once.

... Bob (Grateful Diver)

 

[DevonDiver]

The last time I dove off our coast over the weekend all 4 of my dives went into deco for a few minutes which happens a lot of the coast of NC because of the depths.....

No.

It doesn't happen because of the depths. It happens because the dive is not planned effectively and/or the divers do not stick with that plan and choose to disregard their instrumentation.

 

[MXGratefulDiver]

I am not surprised that you don't see a problem with it. You dove a weekend and ALL 4 of your dives went into deco? You ran yourself over every time? That does Not happen a lot by responsible divers. That happens for reckless, careless divers.
It has nothing to do with the depth off the coast. I urge you to step back and really examine your dive practices. I would not want to see you in the accidents forum, but if you continue to dive this way, we will.

Ah ... having dived with BDSC I don't think he's reckless at all. Perhaps a bit aggressive with his profile, but not one I'd be worried about being able to handle himself underwater.

Things don't always translate well on the Internet. That said, you'd want to have some skills and the ability to manage your air supply adequately before diving that aggressively ... not something I'd recommend for a less-experienced diver ...

... Bob (Grateful Diver)

 

[BDSC]

I am not surprised that you don't see a problem with it. You dove a weekend and ALL 4 of your dives went into deco? You ran yourself over every time?

So? What's the big deal with that? I go into deco by 3 or 4 minutes. I am with my buddy the entire dive and he has a pony with him just in case it's needed. We hang together doing our deco/safety stop. I get back on the boat with just under 1000psi left in the tank. Where is the danger in that? There is approx. an hour and a half surface interval before our next dive.

That does Not happen a lot by responsible divers. That happens for reckless, careless divers.

What was reckless and careless about my dive? Is it just the fact I went into deco that makes it reckless and careless? What should I have done different?

I urge you to step back and really examine your dive practices. I would not want to see you in the accidents forum, but if you continue to dive this way, we will.

I certainly hope I don't end up in that forum. But if I do make it there, it won't be because I go into deco by a few minutes from time to time. Most likely it will be because I will solo dive now and then and have never had a "solo course".

 

[BDSC]

Ah ... having dived with BDSC I don't think he's reckless at all. Perhaps a bit aggressive with his profile, but not one I'd be worried about being able to handle himself underwater.

Things don't always translate well on the Internet. That said, you'd want to have some skills and the ability to manage your air supply adequately before diving that aggressively ... not something I'd recommend for a less-experienced diver ...

... Bob (Grateful Diver)

Thanks Bob. There are times I will, like you said, dive a little on the aggressive side. But before I/we do such a dive, my buddy and I will always discuss the dive before hand and make sure we are both comfortable in what we are doing.

 

[CaveMD]

I second the offer Rita made, I spend a good bit of time at ABWA. I've got most of next week off and will probably be there a good bit.


-Hunter

 

[CaveMD]

39 min of deco.....how can this happen????
First of all you need to have a basic idea of you deep and times even without computer.
He must have seen the computer counting down 5,4,3,2,1,0 and that up again till 39????
39 min deco must be a long time at great deep

No one can be that silly, or??

My best guess is that it was a repetitive dive and the individual did not look at their computer to see how much NDL they had until they were at depth already and were probably just barely within NDL when they splashed in for the 2nd. Assuming he was at 130-150' and thought he had 5 min ndl and stayed for 5 at 130+. I can see him potentially running up a big deco obligation on a single 80 staying for an additional 5 minutes of bottom time after he already had 5 min at 10'.