Calculation on having ENOUGH air for DECO

[MXGratefulDiver]

All legit points. I just want to be a little clearer and get some opinions. By no means will I dive into the deep end of the pool and try deco without proper training. I just thought there was a simpler formula. As for diving to 130 feet...I am comfortable diving 110 and have done numerous dives to 110. I am no means over confident but comfortable. The relief on my 110 foot dives is 70 feet. The relief on this wreck is at 80 feet...so there is plenty to see in between that.
Again I value all opinions and advice. Thank You

Captain, there's a bigger difference between 110 and 130 than might be apparent ... given the accelerated NDL and gas consumption rates at those two depths. But the simplest answer to your question would be to calculate your average air consumption, break the dive up into segments that allow you to calculate your average depth for each segment (and thereby calculate how much gas you would need for that segment), add them all up, factor in how much gas you want to reserve, and if (as appears to me) you're doing this dive alone double your reserves as a contingency ... and by all means, if that's the case, keep some of this reserve in an independent, redundant air supply.

To be honest, this seems like an imprudent dive plan for someone at your experience level ... there are things that can go wrong that you haven't even imagined yet, much less trained for, and once you break the NDL barrier you've effectively removed going to the surface as a bailout option. So you'd better know how to deal with things going wrong while at depth ... and that's going to include some factors that you simply won't be able to learn about on the internet.

All that said, you're an adult, and can make adult decisions. Start by learning gas management, as Andy said. Here's an article I wrote on the subject for my AOW students ... most of whom have similar experience level that you currently do. Although the intent of this article is specifically for divers staying within NDL, it'll help you begin to understand the basics of air management, and calculating how much gas you'll need for a specific dive plan, so you can be assured that you're carrying adequate amounts for the dive.

NWGratefulDiver.com

... Bob (Grateful Diver)

 

[Basking Ridge Diver]

That being said what is the calculation to figure out actually the depths of the deco stops and if I would have a enough air to do so.

If you can read a dive table you can figure that out just by looking what your deco obligation would be in the simplistic terms.

If you look at 130 feet for 20 mins your obligation is 10 mins of deco.

Figuring out your breathing rate and how much gas you would need is also easy enough if you know your breathing rate. As someone mentioned earlier you could use 1 and figure it out.

What the others are mentioning is for contingency - what would you do. If you got excited - would you have enough gas? If you had an incident - would you have enough gas? If your buddy had an issue and you had to share your gas - would you have enough? All of these issues are important to think about before you make that dive.

I tell my kids all the time - anyone can dive - not everyone has the knowledge to deal with an emergency or incident. Get the training is the best advice.

 

[tursiops]

Well, in round numbers 130 ft for 20 mins is 5ATM or 5 times your SAC; assuming 1 cuft/min, that's 20 cuft at the surface, and 100 cuft for being at 130 ft. Ignoring time to get to 130 and back again (not trivial), You'll need at least 150 cuft for the dive, plus transit time, plus deco time. Doubles it is. This is what you learn when you do your training.

 

[Storker]

once you break the NDL barrier you've effectively removed going to the surface as a bailout option. So you'd better know how to deal with things going wrong while at depth ...

This is the reason that - IMNSHO - people who aren't willing to invest the time needed for proper skills training (i.e. people like me) should stay the heck away from even "light" deco and live with the limitations that no-stop diving impose.

 

[KenGordon]

At 40m you will be using gas 3 times faster, at least, that at the stop. So 3 minutes late leaving the bottom is the gas for about 10 minutes of deco. At that depth you will be significantly narked. Your risks are much greater than for a similar length of deco dive shallower.

Your end target may be such a dive, but to get there somewhat safely you need to take it gently and work up. This will mitigate the consequences of it going wrong and reduce the chances of it going wrong.

This would be a reasonable back gas deco dive with a twinset. Arround here that is not unheard of as a single and pony dive - but usually by people with many shallower deco dives first.

Those depths are proper. Don't be fooled by the 'recreational' label. Have a plan, make sure that any single thing going wrong will not kill you.

Training helps, the instructor can tell you about new and insteresting ways stuff can go wrong and can teach you the techniques required to avoid them.

We are lucky in that there are many wrecks in reasonable (20-30m) depths that make excellent dives without a big risk. This means that usually people are quite comfortable by the time they get to more challenging depths.

 

[oldschoolto]

I'm totally self trained... I learn really well reading and doing things in what I like to call baby steps... When I started wanting to go deeper and longer I took baby steps.. I would do trial dives that would be NDL, But were dove as if I had a Deco obligation.. Back in the days before computers we used the Navy Tables, We learned them good enough to recall them from memory ... As almost all my diving was solo, I always had a steel 72 hanging at about 12'-15' so i'd not have to surface before I had all my Deco done if I had a problem of some sort...

But, The most important thing is to be able to keep your cool when the sh#t hits the fan and things start going wrong.. You'll need to be really honest with yourself... Don't put on a pair of rose colored glasses and blow smoke up your own a$$. It'll get you killed....

Good luck...
Jim..

 

[DevonDiver]

Same difference...I could have also said the IANTD advanced nitrox. Again the point is to get more training.

What @boulderjohn suggested was a single course (4 dives) which exactly matched the OPs goals.

An Advanced Nitrox course doesn't provide specific training or certification to conduct decompression dives. The Tec40 does... exactly within the parameters the OP wants.

The OP doesn't need to use >100% O2, nor does he need accelerated decompression.

So....not the same difference.

 

[Captain Mikey Likey]

Again...I just want to be clear on what I want to do and what I am doing. I understand the basic decos are on the dive table but was curious of the input. I always find it interesting old school thought compared to new school. I guess the moral of all this is training...training and training... which I intend on doing. I am a firm believer in knowing your limits and by no means taking any of this lightly and by no means do I intend on diving this without a buddy. Reason I posted here because of the experience you all have as to my lack of. By no means am I taking opinions as training. I am working my way up and am presently taking a nitrox course. This forum def shed some light and its appreciated.

 

[DevonDiver]

Decompression (technical) diving training isnt just about kit and tables... find the right instructor and they'll take your whole diving ability and wider understanding to a currently unimaginable level.

That can go a long way to making your diving a much more satisfying past-time...so it's quite a good investment all-round.

You can do a course like Tec40 with a single cylinder and pony, so there's not even a substantial investment in equipment needed.

However, if you were likely to progress to further tech training in the future, you're better advised to start any tech training in dual cylinders from the offset.

One tip for divers at your level: If you intend to conduct advanced dives, focus first on perfecting your basic skills.

What most entry-level technical students invariably struggle with is the refined level of fundamental skills needed. These skills include: precision buoyancy control, proper trim, situational awareness that doesn't degrade under task loading, propulsion techniques, detailed dive planning, team and communication skills.

 

[flymolo]

Decompression (technical) diving training isnt just about kit and tables... find the right instructor and they'll take your whole diving ability and wider understanding to a currently unimaginable level.

That can go a long way to making your diving a much more satisfying past-time...so it's quite a good investment all-round.

You can do a course like Tec40 with a single cylinder and pony, so there's not even a substantial investment in equipment needed.

However, if you were likely to progress to further tech training in the future, you're better advised to start any tech training in dual cylinders from the offset.

One tip for divers at your level: If you intend to conduct advanced dives, focus first on perfecting your basic skills.

What most entry-level technical students invariably struggle with is the refined level of fundamental skills needed. These skills include: precision buoyancy control, proper trim, situational awareness that doesn't degrade under task loading, propulsion techniques, detailed dive planning, team and communication skills.

Likewise, I'd mentioned advanced nitrox and decompression procedures as I've seen them bundled together and I think the skills and material complement each other