Computer decompression.

[mxracer19]

I am the new owner of an oceanic veo 200. what im looking to know is that although it should never happen, if I should extend my dive into the decompression region, is the model on a veo 200 adequate enough to walk me out of the water as a computer designed for decompression would? What are the benefits of having a computer designed for decompression other than games, a color screen, and the ability to switch gasses?

Thanks
-Matt

 

[MN Lakeman]

Even though the manual is a bit cumbersome & redundant in places, you will be able to see that it details carefully, how to climb your way out of decompresion. It will show your deco stops & time them accordingly. As I recall, there is an "up/down" arrow warning you if you are too deep or shallow for the appropriate stops. This is a good question, as I wonder how many divers actually read their manuals cover to cover. I am a dedicated no-deco diver, but I think its important to understand this important function on my DC for the "just in case scenario".

 

[Mark Vlahos]

I am the new owner of an oceanic veo 200. what im looking to know is that although it should never happen, if I should extend my dive into the decompression region, is the model on a veo 200 adequate enough to walk me out of the water as a computer designed for decompression would? What are the benefits of having a computer designed for decompression other than games, a color screen, and the ability to switch gasses?

Thanks
-Matt

I regret that I am not intimately familiar with the veo 200. If your new computer has a decompression feature intended for emergency use in an unplanned decompression situation I would expect that it will get you out of the water just fine. What it will not do is provide you with enough gas. You need to understand that while the computer will indicate that you should stay at a particular depth for a period of time, and then perhaps ascend to a depth 10 feet shallower and wait there for a period of time and repeat this until it allows you to surface. It will not magically put more air in your tank. Your best bet is never to enter unplanned decompression. Monitor the computer and don't let the thing get close to no time remaining, move shallower well before you have no time left. You should remain familiar with tables as the computer will eventually fail... it is just a matter of time. All computers will eventually fail.

Computers that are designed for decompression diving can allow for gas switching, but of course you need to take the gas with you. You also need training in decompression diving. Things like gas planning, and equipment are as important to intentional decompression diving as are tables or computers.

My advice is if you are diving and you notice that your computer is in an unplanned decompression situation, your first and only actions should be to get you and your buddy out of the water safely. You should follow the computers reccomendations for ascending and stopping at the depths indicated for the times indicated. You will most likely only find yourself in this situation at the end of a dive when your breathing gas supply is low so you may have some unplanned problems. Deal with those problems as best you can and get back to the surface as safely as possible.

My decompression procedures class was one of the best classes I have taken. It was more like an advanced diving class than my AOW class was

Mark Vlahos

 

[Charlie99]

What it will not do is provide you with enough gas..... It will not magically put more air in your tank.

To expand a bit more on Mark's observation ..... You are unlikely to have anything other than a 10' deco ceiling when diving a single tank, and definitely won't be below 20' ceiling per USN deco tables. (For example, it takes 30 minutes at 130', or 50 minutes at 100' before the USN tables call for a 20' stop in addition to a 10' stop).

The real problem is how to best use the air (or other gas) that you and your buddy have. An unintentional deco situation and low on gas are likely to happen at the same time. One reasonable response is a 30fpm ascent to the 20' range, then a slow ascent to 10' range while staying down as long as possible. IF you have adequate gas, than a 1 minute stop in the 40' range (or 1/2 of deepest depth) makes sense.

 

[RP Diver]

I am most definitely NOT a deco diver, but twice I had my old USD Monitor 2 switch to deco mode on dives (Bloody Bay Wall at 110' and Maracaibo Deep at 150'). Just as an FYI that brands can be very different, mine was based a very conservative model, and would go into deco when my wife's Delphi was still well within the safe region. Anyway, I was never into deco for more than one minute, max, before notifying my buddy and starting up. In both cases, the computer switched back to normal mode well before I hit 60 feet. All I really did in response was to make my ascent from 60 feet very slowly, spent about 10 minutes at 35', continued a slow ascent, and I took an extra couple of minutes (5 instead of 3) on my safety stop. Because of the conservative algorithm on the computer, air was never a factor on either occasion. It may not have been a perfect solution, but I'm still here and unbent, so it worked.

If you are monitoring your dive as you should be, you should never accidentally get into a "true" deco situation. For me, the deeper the dive, the more often I check my gauges (the time at Bloody Bay I was doing photography and got caught up in the moment, something that has never been allowed to happen again). I am rarely even close to my NDL when I start to ascend to shallower parts of the reef. My trip to Little Cayman last month, I never got out of the green on my Versa Pro, and most morning dives were to 100', with a multilevel profile of up to 45 minutes.

 

[triton94949]

The deco data on the recreational (non-helium) dive computers is simply to help get you out of trouble if you get into it. It is not designed for a planned deco dive.

For a planned deco dive, you need 2 of everything, for openers. On an NDL recreational dive you normally barely have 1 of everything.

If you were trained in deco diving, you would not be deco diving with an air or nitrox computer. Instead, you would be using a VR-3 or similar model.

 

[lamont]

you can take a tank of EAN32 and 'forget' to set your computer to nitrox and go do a reasonably deep dive and see how it behaves when you push it into 'deco'. best to do it on a profile that you've done before on EAN32 so you know your actual limits without having to use the computer.

 

[Rick Inman]

To expand a bit more on Mark's observation ..... You are unlikely to have anything other than a 10' deco ceiling when diving a single tank, and definitely won't be below 20' ceiling per USN deco tables. (For example, it takes 30 minutes at 130', or 50 minutes at 100' before the USN tables call for a 20' stop in addition to a 10' stop).

You actually can get into some deco obligations with a single tank on a third or forth dive of the day, if you don't plan your dives correctly.
With some of the RBGM computers (like the Mares) you might get a one minute deep stop obligation as well as extended shallow stops.

you can take a tank of EAN32 and 'forget' to set your computer to nitrox and go do a reasonably deep dive and see how it behaves when you push it into 'deco'. best to do it on a profile that you've done before on EAN32 so you know your actual limits without having to use the computer.

Most computers will let you test it out in sim mode while sitting in your recliner, however, that does screw up another good reason to go diving.

 

[Diver0001]

is the model on a veo 200 adequate enough to walk me out of the water as a computer designed for decompression would?

The simple answer is "yes". Your computer will typically lead you back to the surface without getting bent.


Having said that, the most important thing about decompression diving is working out your gas requirements before the dive begins. While your computer can tell you what kind of decompression you need, it can't tell you if you have enough air/gas left to do it.......

What are the benefits of having a computer designed for decompression other than games, a color screen, and the ability to switch gasses?

often computers not made for decompression will flash and beep and carry-on at you so much that the important information is masked by the "heart attack". That's what I call "heart attack" mode on a normal computer. A computer that "assumes" you will go in to decompression will be much more likely to just give you the information you need to see without the "heart attack".

R..

 

[lamont]

Most computers will let you test it out in sim mode while sitting in your recliner, however, that does screw up another good reason to go diving.

Its not quite the same as having your computer go into "heart attack mode" while you're narc'd and under 100 fsw of water. And you notice better how it behaves when you ascend (the suuntos will typically clear the deco obligation somewhere in the 30-60 fsw range for smaller deco obligations if you ascend slowly -- which can be difficult to really simulate).

And if you do a dive to the NDL limits of EAN32 with your computer set to 21% and do a 10 min+ hang at 10 fsw to decompress the computer, you'll get out feeling really good...

Of course for repetitive diving, I know the suuntos punish you on NDLs for dive #2 after going into decompression (they give you that triangular warning symbol with the '!' in it), so you might want to do this on the last/only dive of the day...