There’s plenty ways the OP could extend his bottom time. The simplest would be carry enough bottom gas to do 10 minutes of deco. But seems his hands are tied if he wants to use some charter boats to the wrecks he wished to dive: He needs a teck cert, so why not bite the bullet and get the training.
Next step for longer bottom times on deep dives?
- Thread starter jf3193
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I agree entirely... But my point is not about naming the "light deco" diving as rec or tech. My point is that this "light deco" is a SAFER way of diving than "riding the NDL"...
This is taught here since the first OW course. The concept is that it's wrong to consider the NDL as a "safety limit"; and that going beyond NDL is not as safe as staying within it.
When we are dealing with these not trivial dives, beyond 30 meters, always very close to the NDL for maximizing bottom time, and with environment not particularly easy (wreck, current, limited visibility, rough sea, etc.) a dive planned to be sharply within the NDL is, in my opinion, quite hazardous. Any minimal inconvenience and you are in deco, without being properly trained, equipped and scheduled.
So here we train rec divers to deal with deco obligations properly, carrying enough gas (even if not a dedicated bottle with high oxygen percentage, as it gives almost no advantage for a deco obligation of 10 minutes in air, which reduce perhaps to 6 minutes in pure oxygen), proper redundant air source (so a CESA is never a need), and proper procedures for conducting deco stops in safety (deco bars below the boat, with additional bottles, etc.).
I did always find quite misleading the US approach which states that NDL is a safety limit, and going beyond the NDL is hazardous and requires tech equipment and training. This pushes people to try to stay sharply on the edge of NDL, instead of learning proper deco procedures. So they plan the dive with not enough gas (according to our standards), with not enough redundant equipment (a simple octopus reg on an AL80 is not enough for me), and without setting up proper facilities for conducting safely deco stops even in a rough sea.
A simple definition of "Recreational decompression" would only be on your backgas and for a limited amount of time.
Adding cylinders and other gasses is technical -- needs sorted core skills plus additional skills (gas switching, planning, etc.)
As mentioned above, some European agencies (and others?) include limited decompression in their training. BSAC allows 15 mins as the local conditions generally require deeper diving (wrecks).
For whatever reason PADI doesn't allow this. One could speculate as to why - US litigiousness; better training sandards required; avarice - to sell more courses...
Adding cylinders and other gasses is technical -- needs sorted core skills plus additional skills (gas switching, planning, etc.)
As mentioned above, some European agencies (and others?) include limited decompression in their training. BSAC allows 15 mins as the local conditions generally require deeper diving (wrecks).
For whatever reason PADI doesn't allow this. One could speculate as to why - US litigiousness; better training sandards required; avarice - to sell more courses...
I'm not an instructor, so I defer to pretty much everyone else here on these topics. But I do just want to stand up for the US approach to teaching the NDL as a bright line.
The argument you really want to have is why are we letting people with limited training scuba dive in the first place. And we all know that the VAST majority of people with C cards are very casual divers who might do it on holiday if time permits. Who would have absolutely no idea what their SAC rate is. Who couldn't explain the physics or math behind basic recreational nitrogen loading at gunpoint. Who don't know what the computer is actually computing. Whose dive plan is "follow the DM and surface when he tells you to".
I'm not trying to be arrogant or elitist. I'm just describing reality of scuba diving on planet earth. These people aren't here on SB, and the people in this thread probably don't dive with them. But the agencies know that this is their audience. So given all of that, it's probably safer to just tell them at the basic levels of training "don't exceed NDL" than to say "if, despite your planning you DO exceed NDL, this is what is happening and here is how to do a safe, staged ascent with a minimal deco obligation".
The small percentage of people who actually become scuba divers as a hobby will learn more. But I can see the advantage of this approach to teaching OW divers, assuming that we are no longer doing the six week long YMCA style entry-level courses that were taught in the 60s.
BSAC teach more that 15 min deco.
Advanced Mixed Gas open circuit to 80m
Advanced Mixed Gas CCR to 80m
Dives beyond these limits require the National Diving Office’s approval (for insurance purposes).
Most of the divers I have certified over the years hold a BSAC Recreational diving qualification. Most have never chosen to take any of the 'technical' qualifications. Once, Nitrox was considered technical, now it is embedded in the core diver training, i.e. it is automatic if you complete the recreational qualification.
My second and third qualifications where Recreational diving qualifications.
My second diving qualification - BSAC Sports diving qualification states.
Qualified to dive with divers of the same grade or higher, to a maximum depth of 50m, including dives requiring compulsory staged decompression.
The modern BSAC sports diver qualification states
- Conduct dives with an Ocean Diver within the restriction of the conditions previously encountered by the Ocean Diver.
- Conduct dives with another Sports Diver within the restrictions of the conditions already experienced during training or previous experience.
- Conduct dives with a dive leader or higher grade to expand their experience beyond that already encountered.
- Dive to a maximum depth of 20m initially. Extending the depth experience under the supervision fo a NQI or Dive leader or higher, in sensible progressive increments. To stay within the MOD at all times.
- Use breathing gases up to Nitrox 36
- rescue a casualty and provide basic life support.
It is a recreational diving if the dive does not include accelerated decompression, Rebreathers, Helium, or mixes richer that 36% O2. (Or PAID reward!)
There is only one diving qualification with the BSAC that does not allow staged decompression. That is Ocean Diver, who can only perform no-stop dives to a maximum depth of 20m. But they can use Nitrox!
Ocean Diver is roughly equivalent to PADI Open Water.
When I did my Sports Diver. At that time, the diving grade below, required you to dive with an instructor or dive leader at all times.
There is a blurring of the lines.
A BSAC Sports Diver depth restriction change if they complete the Twinset course.
If as a sports diver you choose to step on to the technical training rung, things change again. The technical qualifications include ADP, Mixed Gas, CCR etc.
The fact that some American charter skippers are unaware that some recreational diving qualifications DO qualify the diver to do staged decompression and use Nitrox as a breathing gas, is a problem with American charter skippers. In fairness, it is not reasonable to expect a charter skipper to understand each and every diving agency qualification.
It is only the US Diver recreational training agencies that have an issue with dives involving staged decompression. Most of the other diver training agencies see it as part of the standard recreational diving qualifications.
Gareth
Mike1967
Contributor
6 weeks????
My OW course in 1975 was SIX MONTHS long...
Ok, probably too much..
But even today a FIPSAS-CMAS course is three months here!
I do not agree with you that it was a good idea to demolish these well-featured (and task demanding) OW courses to the point of releasing a diving certification in a weekend.
Sorry for being "old school" on this.
And personally I think that the continuous reduction in number of new divers is also due to the fact that it has been made too easy.
For a youngster it is not presented as a difficult, task demanding activity, as it was for me in the seventies.
If it is a sport suitable for a 60 y.o. fat lady, who cannot even swim without fins, it cannot be something exciting for a youngster...
Some of us 50-something "fat" old ladies do more adventurous diving than the tropical stuff.
The youngsters say diving is too scary and dangerous. 
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