Qualification Depth Query

[Fiona]

This is just something I have been thinking about recently which was prompted by various courses people do in addition to their original qualifying agency.

I have a BSAC qualification which allows me to dive to 50m if I want to, normally in the UK I don't and my depths are usually about the 30m but if there was a dive I wanted to do in say 45m then I would, although it would be quite short as I am not really in to deco.

I rarely dive air so most of my diving is done on a 36% but I would reduce the O2 content for deeper dives, now Davey Willow recently posted on UKD that he would use trimix for dives deeper than 30m and I am wondering why this might be.

The other question is if you have a qualification for which the max depth is 30m for instance AOW (I think that is right) and then you do a course from say TDI like Advanced Deco Proceedures, does this then qualify you to dive to a much deep depth or should you still be using a max depth of 30m. This is from an insurance perspective not a personal one.

The reason for the question is as lots of people now dive on holiday what would you do and especially for the DIR guys (and no I am not having a pop, blame Mr Willow ), we will assume trimix isn't an option as it would cost far too much and not always available on liveaboards.

This is not an agency/style thing I am genuinely interested.

[Richie]

Originally Posted by Fiona

This is just something I have been thinking about recently which was prompted by various courses people do in addition to their original qualifying agency.

I have a BSAC qualification which allows me to dive to 50m if I want to, normally in the UK I don't and my depths are usually about the 30m but if there was a dive I wanted to do in say 45m then I would, although it would be quite short as I am not really in to deco.

I rarely dive air so most of my diving is done on a 36% but I would reduce the O2 content for deeper dives, now Davey Willow recently posted on UKD that he would use trimix for dives deeper than 30m and I am wondering why this might be.



The other question is if you have a qualification for which the max depth is 30m for instance AOW (I think that is right) and then you do a course from say TDI like Advanced Deco Proceedures, does this then qualify you to dive to a much deep depth or should you still be using a max depth of 30m. This is from an insurance perspective not a personal one.

The reason for the question is as lots of people now dive on holiday what would you do and especially for the DIR guys (and no I am not having a pop, blame Mr Willow ), we will assume trimix isn't an option as it would cost far too much and not always available on liveaboards.

This is not an agency/style thing I am genuinely interested.

Fiona,

Trimix below 30m to offset nitrogen narcosis. A bit drastic in my opinion but great if you can afford it. A totally clear head at all depths must be a bonus.

I have a basic problem with a depth qualification. A diver needs to know the consequences of depth and have the basic skills to enjoy or survive them depending on your viewpoint but 40m in the Red Sea is a very different prospect to 40m in the North of Scotland at 4 a.m. in January.

I think every diver should experience depths at least a little deeper than those at which they plan to dive - if they find themselves at a greater depth than planned then the level of concern/panic should be minimised.

From the insurance perspective, many policies are depth limited any way unless you are rescuing someone. For unlimited, or unreachable, then the "deepest" qualification should carry weight.

Cheers

Richard

[Lou]

As far as I understand it, Fiona, PADI and then TDI, in the example you give, would give you the qualification up to 45m (?) for Deco Procs.

If it all went by your original agency qual then you would never be able to progress, or to swap agencies.

The trimix argument is one of reducing narcosis, but where you begin to use it and under what circumstances is all personal preference. If Davey doesn't want to dive without it below 30m then all power to him, but I wouldn't put that exact limit on my diving.

[John N]

The trimix usage beyond 30m is to reduce the incidence of nitrogen narcosis.
Different people have different opinions about the safe depth to dive using air.

Diving in the UK particularly, you will probably be narced at 45m which might not be very nice if you don't normally dive to that depth.
Nitrox is not supposed to help with narcosis either.

I have the TDI Adv Nitrox/Deco badge and it allows diving to 45m, so yes for insurance purposes I should be covered to that depth (check the small print though).

If it's a dive you want to do then I would do some work up dives first rather than going straight from 30m dives to 45m dives.
You would have to do it on either air or a pretty weak nitrox mix - do the calculations and see.

[MATTBIN]

Fiona
the way I understand it is that your 'agency' quals are recommendations only, although how an Insurance company would see that is open to debate.
I have Padi aow (which I think is 30m) but I also have Tdi basic nitrox which says 40m. I would use that card if I wanted to dive to say 36m. Bear in mind, as we have discussed before, that certain deep cards do not require you to dive to the max possible depth. It would for instance be perfectly acceptable to do a pAdi deep (i.e. qual to 40m) without going beyond 25m, which is already covered depth wise by the AOW card.

I would suggest that people use trimix below 30m because they wish to reduce the Nitrogen (hence narcotic affect) without using Oxygen as this pushes up the chance of ox-tox, and so regard Trimix as the safest alternative.

Personally I want Nitrox to whatever % is applicable for the dive down to a personal max of 35m, even in gin clear waters, not necesarily because I worry about narcosis (although I would) but for time of dive perpective, without twins I d get about 12 minutes!! And I'd want a pony at anything below 25m (or a damn good buddy).

At least that's the way I see it.
HTH
Matt

[Fiona]

Originally Posted by Lou

As far as I understand it, Fiona, PADI and then TDI, in the example you give, would give you the qualification up to 45m (?) for Deco Procs.

Thanks Lou that is the answer I was looking for.

[Fiona]

Originally Posted by John Nortcliff

If it's a dive you want to do then I would do some work up dives first rather than going straight from 30m dives to 45m dives.
You would have to do it on either air or a pretty weak nitrox mix - do the calculations and see.

John I was interested only in the multi agency qualifications, my information was for background only.

[Ainsleyberryman]

DAN, I seem to recall, are happy to insure you to 130m after that you need to ring them. They were happy with my 105 even though my Advanced TMX card says somthing like 90m. They were more concerned with the partial pressues and mixes than the actual depth when I rang them.

[Phoenix]

My ANDI card states "without depth limits", don't know how far I'd push that one though.

Ian

[Fiona]

Opps, is this a virtual slap wrist for not posting in the right place wondered where it had gone and there was me thinking it was chit-chat