Would you really know what was going on if your computer went into Deco...?

[Genesis]

I can get WELL into required deco on an AL80 Mike, particularly if I have AIR in that tank instead of Nitrox.

I do agree that doing deco diving on a single tank without redundancy is not particularly smart, in that a single failure can easily "hose" you.

 

[MikeFerrara]

There is no "magic" about decompression. Yes, it can badly hurt or even kill you if you do it wrong, but all dives are decompression dives. If you want to test this go ahead and stay to the NDL on a nice 100' dive and then do a polaris ascent, and let us know how much the chamber bill is, because you're VERY likely to end up with a chamber ride out of that. NO, YOU SHOULD NOT DO THAT, FOR THE SARCASM IMPAIRED!

I intentionally dive with required decompression from time to time, and I have no "formal" training. I have made a study of how it works though, and I certainly don't do it without the required redundancy in my equipment to INSURE that I can meet the required schedule. Decompression is an overhead that is just as "real" as a cave; if you cannot make your stops for any reason you are quite likely to end up hurt or worse.

No, there's no magic. If you take the time and effort to learn what you want for a schedule and have the right equipment and have the in-water skills and plan for it it's no big deal.

I'm with Uncle Pug though, this thread is proof that computers rot your brain.

 

[Genesis]

Actually, I think that the computer MANUFACTURERS are interested in brain rot. Read the Suunto manual sometime Mike - put aside your knowledge of deco, and just read it, pretending you're an OW diver - then tell me that it doesn't lead you to believe that the "right" (as in "fastest, perhaps even safest") way to handle the "ASC TIME" light coming on is to go immediately to the ceiling displayed and wait until it moves up, doing so when it does.

I think there's a good argument to be made that this is exactly how most "recreational" divers will interpret that display and manual - and that bites.

Then again so does PADI's and SSI's "omitted decompression procedure" - they both basically say the same thing - go to 15 feet and SIT!

 

[truva]

Equipment failure like a free flow or a busted low pressure hose? The point is that on any dive but especially a dive requireing staged decompression each diver needs enough gas for the worst case situation which is to get both divers back if one suffers a total gas loss at the worst time. If you're shallow and don't have a decompression obligation you can argue that the plan is an ESA. Bad idea with a decompression obligation (even a little one)

Diving common recreational equipment (AL 80) it's kind of hard for most people to get very far into deco on a tank of gas unless you're rather deep or it's a repetative dive and that's really a bad time to risk messing up deco or missing a stop.

Are these people who are incurring a decompression obligation to test their computers decompression mode function going to have that reserve gas diving what? an AL 80?
If they don't know ahead of time what the schedule is going to be how do they plan their gas?

Sorry, intentionally incuring a decompression obligation with recreational equipment and your run of the mill recreational training and blindly trusting your computers schedule is really, really NOT smart.

I guess that's my story and I'm stickin to it no matter how much I'm accused of pushing people to do things my way.

Actually we can find ourselves in this situation a lot since we dive 100’s. But that’s what the Al13’s are for which are plenty big enough for the profiles we dive. We don’t go into overhead environments hard or not without each having one of these small ponies. All the training in the world is useless without a little common sense.

Truva

 

[Genesis]

13s are not enough to bail from significant depths.

A friend of mine who thought they were nearly killed himself last summer that way.

 

[Gary D.]

I'm from the old school but I think I may have missed something here.

First off I'm like a lot of you where I can easily get into deco modes on a single 72 or 80. There are times where I'll suck a tank quick but most of the time I beat most I dive with except my wife. She seems to come up with more air than she went down with?????? She makes for cheap air fills because the woman doesn't breathe.

It's been a while but do they still teach that "Dive time" is from the time you leave the surface until you leave the bottom. "Decompression or assent time" is from the time you leave the bottom until you reach the surface. The "Total dive time" was the two added together.

Somehow either me or this thread got way off track. It started out as a computer going into a "Deco mode" which is no big deal. Then it evolved into needing training and 10K worth of gear for ANY Deco dive. ?????

You Deco on every dive if you want to or not. No choice here. Minor short little stops are no big deal. A long dive with serious Deco needs to be treated different. Normally if it's a short 10' stop it's not a big deal. Getting into long 10' or deeper stops can be a problem. Start seeing stops at 20', 30', 40' or more could be a recipe for disaster if your not ready.

Genesis is very right when he said Deco is an overhead enviroment. But here again there are exceptions. Unlike the ice or a cave where you can't go to the surface, there are times where you punch through the overhead and handle the problem afterwords.

Most of this sport is not one way and one way only. There are a lot of exceptions that can be done safely.

I'd feel better doing a 20 minute Deco stop on a single 72 than someone jumping into the water with their air off and overweighted with the quick releases unreachable. A saying we use at work a lot is "You can't legislate against stupidity". With some people all the rules in the world can't protect them.

A couple of years ago 4 of us went down with 4 computers each. The results were expected. They went from mild to wild and they seemed to stay close together as to brand which was good. Some were ready for a Deco stop while others were 5 minutes away but again they stuck together as to brand name.

The bottom line here is to just enjoy your diving, don't over think it and stay within your level of comfort.

Having a lot of redundent equipment can go to far and be a bigger problem. Some people can't handle the basic equipment let alone having two of everything. Some people get so dead set on two or three of everything I'm surprised they don't require two bodies of water incase the one your in dries up.

Gary D.

 

[ArcticDiver]

Equipment failure like a free flow or a busted low pressure hose? The point is that on any dive but especially a dive requireing staged decompression each diver needs enough gas for the worst case situation which is to get both divers back if one suffers a total gas loss at the worst time. If you're shallow and don't have a decompression obligation you can argue that the plan is an ESA. Bad idea with a decompression obligation (even a little one)

Diving common recreational equipment (AL 80) it's kind of hard for most people to get very far into deco on a tank of gas unless you're rather deep or it's a repetative dive and that's really a bad time to risk messing up deco or missing a stop.

Are these people who are incurring a decompression obligation to test their computers decompression mode function going to have that reserve gas diving what? an AL 80?
If they don't know ahead of time what the schedule is going to be how do they plan their gas?

Sorry, intentionally incuring a decompression obligation with recreational equipment and your run of the mill recreational training and blindly trusting your computers schedule is really, really NOT smart.

I guess that's my story and I'm stickin to it no matter how much I'm accused of pushing people to do things my way.

Is the person trusting their computer doing any more blind trust than the person who trusts a table? Aren't both constructed with the same science, just one samples more frequently and so should give more accurate results?

Now I have never dove with a Suunto so I can't vouch for that. But the computers I have used all tell the diver to use a specific ascent rate to ascend to but not above the specified deco ceiling. That is what a table says too. Of course their may be multiple, sequential ceilings with either device.

So, if I were going to answer the original question I would say: Yep, I do know what to do if my computer goes into deco. I read and I understand my manual. If I haven't used it for a specific function in awhile I reread it before the dive. I trust it to give me good advice just like I trust the tables it replaces. So if you want to know too; read your manual and practice. Always remembering your basic scuba skills that don't change wherever you are in the water column.

Oh yes, since the original question didn't ask about planned, staged decompression requiring multiple gases I didn't either.

 

[MikeFerrara]

13s are not enough to bail from significant depths.

A friend of mine who thought they were nearly killed himself last summer that way.

They might be enough for truva.

 

[billseamon]

I wouldn't recommend doing a decompression test dive to learn your computer. Read the manual multiple times and dive alot.

I have an Aeris 750 that I have been told is 15 year old technology. It has a decompression bar chart and I always come up when it hits the yellow, and wait at 15 to 20 feet until it goes back in the green.

Now about PADI. I got my basic openwater certified by NAUI in 1972, and just got my nitrox from PADI this year for a live aboard. A friend is a PADI instructor and several of us got nitrox certified. The instructor bought a O2 tester for our trip with what he charged for the class. However, I lost all respect for PADI when I saw for $15.00 cert card I could get Certified for Boat Diving. There are some things that you should have enough common sence for, and if you don't either don't do it or if something happens while doing it, look at it as a little chlorine in the Gene Pool.

I dove in high school and college with a fire department recovering bodies and other things dumped in the water and learned alot from them. Also I
joining a dive club at the YMCA and learned alot by diving with some of the more experienced divers. If you can't find a dive budy with alot of experience in decompression diving and have the required equiptment I wouldn't do it.

About 5 years ago, another NAUI instructor friend said who I dove with alot, you have done all the dives, study to book, take the written test and I will cert you for NAUI Master.

Now I believe any instructor certified by PADI, NAUI, or who ever is capable of teaching basic open water scuba, however, unless that instructor is diving caves, wrecks, deep, ect on a regular basis, I would trust getting certified in such a speciality where the results of Murphy can be the end of you. Aside from being competent with basic underwater skills and not panicing, I believe the real benefit for the specality training is learning the necessary backup required to attempt something that can kill you.

Well just my two cents worth.

 

[MikeFerrara]

Is the person trusting their computer doing any more blind trust than the person who trusts a table? Aren't both constructed with the same science, just one samples more frequently and so should give more accurate results?

When it comes to decompression I wouldn't say that I really trust anything but if a table and a computer use the same model they'll yeild similar numbers. However some mentioned in this thread going into deco to see what the computer does. The first most important thing is to know that ahead of time. Yes? Even if we go so far as to say that the plan might change because of planned for or unplanned for events surely we want a plan that can take that change into account. right? So the first point is looking ahead and not behind. That way we know that we have enough gas and can handle a problem.

When it comes to models you need to make your own choice but I start stops deeper than a haldanian model. Even on a no-stop dive my "safety" stop starts deeper than 15 ft. As it is, for many of the dives that are done every day as no-stop dives I would do what I would consider minimum deco. I could go on and on but the point is to become familiar with the decompression stratagies that you're comfortable with and incorporate them into your diving before you have a decompression obligation.

You can do it because the computer says so or you can do it because it's what you think you should do. One way is easier and one way you make the choices. The other way some one else decides.