Equipment for Adv Nitrox and Deco Proc

[HowardE]

I was told (for my class) that I need an SMB or Lift Bag.

 

[Meng_Tze]

My instructor has told me that he once cracked his manifold (primary side) in a cave. He isolated his tanks, breathed off of the leaking tank until it was empty, while making his way back out, then went to the second tank & breathed it down all the way & still had about 75- 100ft to go to get to his stage bottle. He said it was one of the times he didn't think he was going to make it out alive. That's the only case I've heard of that. But it was also technical diving, not open water.

Hmm.

Isolated 1/2 of volume in left tank. Volume should be no less than 2/3 of total volume if you follow rule of 1/3. So 1/2*2/3 = 1/3 of total volume in left tank. This should equal his volume used at max penetration or away from stages.

In right tank he had less than that, but his total volume was more than 1/3 to get out (or to the point of the stage)...... did he break his gas rules.....?

Unless he was in a syphon he should have made it out without issue. But if he was in a syphon he should have had his gas plan adjusted.

Unless something else happened we are not aware of (panicked, lost, entangled, very slow in isolating), I would be wary of either the story or his experience and thus what you get as a student.

 

[Blackwood]

The TDI manuals (Adv. Nitrox and Deco. Procedures) are sorely in need of revision.

Yes, and I hope the revision is more than just a change in font size and pictures.

The current texts are quite lacking. They don't really go much beyond basic nitrox, except with the addition of OTUs. At least, I remember thinking that when I read them.

IANTD's texts are much better from a content perspective once you get past the abysmal writing (if only Tom Mount would apply some of that legendary drive and perfectionism to his written language skills...)

 

[NorthWoodsDiver]

For my deco class I was simply told that either I needed to bring my equipment or bring my equipment simply because he didn't have enough to rent everyone out a whole kit. That excludes tanks kinda.

for the class I have to furnish:

1 set doubles (minimum total volume of 160 cuft) with isolator
1 deco bottle thats O2 clean and at least 40 cubic ft in size.
1 reel
1 spool
1 lift bag or smb
2 back gas regs setup for doubles in a hog configuration preferably (must be DIN)
1 deco reg O2 clean (must be DIN)
appropriate exposure protection for lake superior
1 primary and 2 backup lights
2 cutting instruments
1 back plate and wing with harness
2 computers w/ gauge mode or bottom timers
1 slate
1 O2 analyzer
1 mask and 1 backup mask.

They recommend you bring a second deco bottle and at least 1 stage bottle with the appropriate regs so depending on the class and how things go you can do a bit more experimenting.

I will be bringing everything on the list but I have a deco bottle for 40-50% and for 100%. Tech diving aint cheap, I'm just glad they dont require a canister light or scooter. T

 

[Hoosier]

No rent... Get a double after finding out the most popular double set in your local area.

Get used to the new gear before taking a class. Otherwise, take a private class and be focused on the learning, not passing.

Bring CC... It works everywhere.

The gear list above is only basic gear required. In addition, any nitrox mix for ADV/Deco is much cheaper than Trimix.


Be prepare for breaking one of your saving accounts soon.

My 2 bar...

 

[Blackwood]

No rent... Get a double after finding out the most popular double set in your local area.

I would suggest it's better to borrow some dubs and see how they work for you (in terms of trim, etc.) rather than picking a general consensus set.

I agree with the aforementioned 160CF minimum for dives beyond MDL.

 

[mark99]

The deco reg frankly just needs to be nitrox compatible. The whole O2 clean regulator required thing has in my opinion become badly overblown and taken to uneccesary extremes.

It is the tank valve that poses the major O2 threat and in particualar scuba valves as they tend to open very quickly and are not designed with flow passages that are O2 friendly and have much greater potential for producing an ignition source. In contrast almost any reg that is nitrox compatible will do fine with mixes over 40% up to and including 100% as long as you pressurize it slowly by turning the valve on slowly while the purge is slightly depressed.

O2 cleaning is a nice place to start and a good idea, but an O2 clean reg with 30 dives on it is no longer "02 clean" even if it has only seen O2 compatible gasses. None of them are "pure" they just have less hydrocarbon contaminants than non O2 compatible gasses and contaminants still have the potential to accumulate. Similarly, a deco reg that did a dive or two with non-O2 compatible air is probably still much cleaner than the O2 clean reg with 30 dives on it.

My experience in reading posts on Scubaboard (and other similar sites) is that the advice given by senior and more experienced divers usually tends to be cautionary and conservative, considering the experience range of the readers. You are saying that you can use any reg (that has been originally O2 cleaned) on any cylinder (non-O2 cleaned) any number of hours, and then back on a 100% deco bottle. I know the standard for Grade E air Hydrocarbon level is 5 mg/m3 and for Oxygen compatible air the standard is 0.1 mg/m3. That sounds like a big difference to me. If I use my deco reg say on a 50% mix with OCA for the number of hours I do deco (i.e. not so many), I realize it's not as clean as it started. However I can't see how it could be comparable to using it routinely with Grade E air and then switching it over. How much muck in the regulator is too much?

 

[String]

Dont forget to take a spare mask. You WILL "lose" your initial one at various points.

Practice skills whilst holding neutral buoyancy, practice sending a big whilst holding neutral buoyancy and so on. Ideally you need to be ok at the before arriving on the course.

 

[String]

my 50lb bag has toppled over and dumped some air making it much less buoyant. my team mates 100lbs don't topple over with the same amount of air in them. since they pack the same and cost the same, why not get 100lb?

Or why not just get a self sealing DSMB which cant empty if it topples over and is far smaller and actually designed for the job at hand?

 

[Web Monkey]

Dont forget to take a spare mask. You WILL "lose" your initial one at various points.

Practice skills whilst holding neutral buoyancy, practice sending a big whilst holding neutral buoyancy and so on. Ideally you need to be ok at the before arriving on the course.

That's actually pretty funny.

I've been kicked in the face, bumped my head on things, been in all sorts of ripping current hanging on a line, never carried a spare mask and never lost one.

I started Adv Nitrox/Deco last month, brought a spare mask, was just overing and mine just fell off. Nobody touched it (at least nobody I saw). Nothing hit me. I was just hanging out and the buckle let loose. So I grabbed the spare and swapped it.

Go figure.

Now I'm wondering if it had some help. . . .

Terry