Tech expectations

[Angelo Farina]

My favourite dive buddy that I’ve had is a cmas instructor and we have done a couple of cmas style deco dives. Unfortunately getting my cmas qualification isn’t an option and I’d like to dive “by the book” moving forward.

If your dive buddy is a Cmas instructor, why do you exclude the possibility of being trained/certified by him/her?
Of course a real technical training will provide you better skills and mindset.
The point is if you really need to reach such an advanced level...
Personally I am satisfied of the Cmas recreational limits.
Do we stay horizontal during deco? Usually not, but what's the problem? And yes, for keeping the depth we usually employ a buouy or a metal bar hanging below the boat (not the anchor line).
Do we frog kick all the times? Definitely not: we use powerful flutter kicking in most cases...
Do we penetrate wrecks or caves? Definitely NOT, it is dangerous and there is very little to see inside.
But I fully understand people who want to go beyonds recreational limits, diving deeper than 50m (which requires helium) and using highly oxygenated mixtures for accelerated deco.
I also understand how some people could be attracted by wreck and caves...
So, if you want to achieve these goals, definitely get proper tech training.
If instead your goal is just to go beyond NDL, diving at 40-45 meters max and with some short deco on your back gas, all this does not require technical training and your buddy should be able to train and certify you for such recreational deco diving profiles.

 

[Wibble]

Personally I am satisfied of the Cmas recreational limits.

That's great for you. The most depressing thing about diving on wrecks is how short the NDL time is for depths between 30m/100ft and 40m/130ft. Literally minutes.

You've spent a small fortune on booking on the boat, taking time to get there, getting all the fills, motoring out to the site. Then you dive for 20mins on the target. It seems so completely pointless when you could, with a little more training and equipment, dive for an hour or more on the target with some decompression.

Do we stay horizontal during deco? Usually not, but what's the problem? And yes, for keeping the depth we usually employ a buouy or a metal bar hanging below the boat (not the anchor line).

Horizontal is more comfortable, more efficient for decompressing (your whole body is at the same depth), and a lot more stable to keep your depth. If on a SMB, that shouldn't be hung on, you should be neutral in the water and allowing the line to jump up and down.

If you're on a shot line in a current you'll be flying like a flag. If it's a shot line in no current then come off of it and leave space at the 6m/20ft mark for everyone else.

Do we frog kick all the times? Definitely not: we use powerful flutter kicking in most cases...

Why do you need a powerful kick? Is it some kind of race? Frog kicking is extremely efficient and doesn't kick up silt nor affect flora and fauna above and below. If you're moving around a reef, it's slow and you need to use your other finning skills such as helicopter turns and backfinning for positioning.

Do we penetrate wrecks or caves? Definitely NOT, it is dangerous and there is very little to see inside.

There's so much to see inside a wreck/cave. Try taking good lights with you. It's amazing to swim inside a submarine (a rare experience, but does happen), or inside a wreck even, such as into the holds or any holes that open up. For some -- me -- this is the whole raison d'etre of diving. Seeing things you've never seen before.

Wrecks and caves aren't dangerous provided you are calm, take care, use proper finning techniques and be aware of losing visibility, possibly laying a line if necessary.

Being around a wreck can be confusing if the visibility suddenly disappears, someone kicks up a load of silt and you cannot see your hand. Calmly deal with it. A slow fin forwards to get out, or reverse back, or wait for a minute; you should be stable so nothing's changing. Flutter kicking is a nightmare around silt.

But I fully understand people who want to go beyonds recreational limits, diving deeper than 50m (which requires helium) and using highly oxygenated mixtures for accelerated deco.

You don't need to go deep to benefit from accelerated decompression. A 30m/100ft dive would be 20 mins on air, 30 mins on 32% for the NDLs. Or 70 minutes on the bottom plus ~25 mins of deco with a rich gas; the trick is planning for the failures.

I also understand how some people could be attracted by wreck and caves...
So, if you want to achieve these goals, definitely get proper tech training.

Wrecks aren't really technical diving as most people from their OW dive them around here. It's extremely rare to be able to penetrate more than a few metres inside a wreck, certainly wartime wrecks as they're all degrading and collapsing in as nature recycles them.

 

[Germie]

With TDI an and dp are 2 courses, that is true. These courses together are teached by some other agencies like IANTD as 1 course. There is no deco limit, but limit to 1 decogas and depth 40m with air as backgas.
If you don't want air as backgas, you can do with tdi helitrox (45m) or with iantd advanced recreational trimix (45m, the plus version is 51m). All also with 1 decogas.

With padi you have the 40m course, and then 45m and 50m. After that you can start trimix. To reach full trimix it are 5 courses.
With tdi it are 4 courses, with iantd it are 3 courses to reach the same level at the end.

The best thing is to look at what you want and your financial options. Deep air is teached by padi till 50m, by iantd till 54, by tdi till 55 by head. In all cases it is not the 2nd or 3rd course in the technical row of courses. CMAS 3* gave you a 60m on air cert, but now cmas 3* is limited to 40m (so the older users have of course still their older limit, even if that is not on the card). Bsac goes to 50m on air.
Deep air is cheaper than trimix, way much cheaper nowadays. But there are some big disadvantages when diving over 50m on air.

From what I read now for you a 40 or 45m cert with some accelerated deco would fit. Planning decodives on backgas I would never recommend. Also a technical diver don't hang on an smb to hold his depth. Stay horizontal is also better thing than stay vertical.
Talk with some instructors, and make a choice. This is more important than the color of the cert.

 

[boulderjohn]

With padi you have the 40m course, and then 45m and 50m. After that you can start trimix. To reach full trimix it are 5 courses.

although PADI TEc 40, 45, and 50 are three courses, they can be taught as if there were one course, with the order of the dives changed for efficiency and removal of redundancy and repetition.

The Trimix course is actually one course, but it can be divided into two (normoxic and hypoxic).

 

[MB NZ]

What you want to do is still recreational diving, down to 50m with deco, according to European agencies such as BSAC or CMAS. My fully recreational certification is for 50m max, with deco on back gas (no accelerated deco).
And of course we started diving using twin tanks, which are usually more streamlined and balanced than a single large tank.
So, if you you just want to dive deeper and with some "light" deco, there is no need to enter the technical diving world, you can do this staying within the recreational system (with the proper agency, of course).
In my diving career I never felt the need to step over our European recreational limits, and go into the tech world.
Of course, if you want to PENETRATE in such a wreck, then you really need technical training (and equipment, and team procedures, and a specially equipped support boat, etc.).

This is where I got to 20 years ago when I was guiding on the Zenobia in Cyprus. 42 metres to sand, but the wreck comes up to 18 metres, so it was far from square profile diving. We did a lot of diving with up to 20 minutes decompression on back gas. Sometimes air, sometimes nitrox depending on the dive plan. I was diving a single cylinder, a 15L for the bigger dives! My SAC was impressive in those days. There was a "hang tank" that the customers sometimes used. Obviously, we were pushing things a little and it's very open to criticism. Subsequently, I dipped my toes in to twinsets and technical training. I got to IANTD ART and very much enjoyed it at the time, but it's all too much hassle for me these days. Each to their own though, if you enjoy it, no other justification is required!

 

[Celt]

I envy you, 50m or shallower is the happy place. Crank up the O2 and there’s not a dive you can’t make on backgas twins.

 

[Wibble]

I got to IANTD ART

When I was looking at which "ANDP" course to do, ART (Advanced Recreational Trimix) had some strange restrictions: 15mins max deco or something like that. TDI's ANDP at that time had a 20% cap on helium in the mix, but had "unlimited" deco, therefore was much more realistic for English Channel diving to 45m/150ft.

Are you now considering the move to CCR to allow cost-effective deeper diving, or at least helium in the mix to take the narc off below ~30m/100ft?

 

[MB NZ]

Yeah, there were some arbitrary rules with ART, but it was worth doing. My diving has gone backwards, just a "recreational" diver now. I don't do much deeper than 30 metres these days and trimix isn't an option where I live.

 

[Tribal]

When I was looking at which "ANDP" course to do, ART (Advanced Recreational Trimix) had some strange restrictions: 15mins max deco or something like that. TDI's ANDP at that time had a 20% cap on helium in the mix, but had "unlimited" deco, therefore was much more realistic for English Channel diving to 45m/150ft.

Isn’t that more like a guideline? I don’t mean that you have to go from no deco to 1hour deco but once you get more experience you can build it up?

 

[Wibble]

Isn’t that more like a guideline? I don’t mean that you have to go from no deco to 1hour deco but once you get more experience you can build it up?

When I was looking at IANTD ART, it seemed to be a 'fixed' amount of deco.

Whilst you can practice and then go well past this, for me it meant that I'd be quickly diving outside of my limits and could have grief with any insurances. Thus that limit (I think it was 15 mins, might have been more), was a non-starter especially as TDI's ANDP set the limit at 20% Helium -- fine for a 45m/150ft dive -- and no limits on deco (except for the enough gas limits...)

The following year it was Normoxic Extended Range and the helium percentage limit was removed along with the floor at 60m/200ft.

IMHO the main benefit of normoxic is having two deco stages, thus having a backup for a failure of a deco stage (e.g. take a couple of smaller rich cylinders, one as a backup to the other, so you can do long shallower dives where you cannot take sufficient backgas to deco out on should the one deco stage fail — granted this is a solo mentality)