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ronnie the rhino · 08-07-2008, 06:22 PM

As i mentioned in my intro i am going to Scapa to do the deep specialty.My deepest dives so far are 25mts at Dost Hill and 20mts in Jamaica.What should i expect at 40mts in the Orkneys?Will i be narked off my head?How scared should i be?

divingdoc1 · 08-07-2008, 06:39 PM

Simple answer! Nobody can tell you! There will be people here who will be out of their sweet noggin at 25mtr, others will tell you that they dont feel anything until the reach 60 meters!

sorry mate, not very helpful i know but it really varies from person to person! I think, however, that you should really build up slowly to reach that 40m mark. Are you doing your deep dive spec while you are up there. If so, i suggest you start at 30 and buile up to the 40.

ronnie the rhino · 08-07-2008, 07:07 PM

Yeah doing deep spec with the guys at Scapa Scuba,not really worried ive no doubt the instructors are pros and will look after me.Plus i guess a healthy respect of the depth wont hurt!

divingdoc1 · 08-07-2008, 07:28 PM

Scapa Scuba are a great bunch and im sure they will look after you well. I geuss they will pick and choose their sites so that you get the most benefit and fun. Good luck with it, and remember to have fun, thats what its all about

PoseidonPete · 08-07-2008, 08:20 PM

You will usually find they build up to it over a course of 4 dives, and even then you will most likely only go to 30 mtrs during the course.

***Jenkins*** · 09-07-2008, 12:09 PM

I did my deep at Stoney so 34m max depth, having already done afew dives to 30m. I think the first thing which will hit you is how dark it gets (especially in the "shadow" of the wrecks) as you go deep in the UK, we did the Markgraf last spring and at 42m you couldn't have seen the wreck without a torch.

Narcosis is very personal, personally I start to feel the effects around 30m and it's abit like being slightly drunk and usually makes me very cautious/wary and obsessive/paranoid about checking guages etc. I have been narked on the 22m shelf at Stoney and once totally freaked out due to narcosis at 35m - not good!

Anyone who dives to 30m and claims not to have been narked is lieing, you may not feel the effects but (just as with alcohol) it IS affecting you to some dregree.

Sakara Drinker · 09-07-2008, 04:04 PM

Jenkins Wrote:Anyone who dives to 30m and claims not to have been narked is lieing,

And what exactly is that based on?

divingdoc1 · 09-07-2008, 04:20 PM

oh oh, think there is a row brewing here!!!! However must agree with jenks on this one. both physiological (im sure a doctor with relevant diving knowledge could answer this one with expertise greater than mine) and emperical evidence (deep dive practical skill test) do show these to be true.

Im presuming here that you (Sakara) are going to talk about diving with Trimix? Im not qualified to talk about that so will bow to your superior knowledge, but surely before you started that you did deep dives on air and were narked at some stage, even if you were not aware of it?

My 2p, please don't shout at me :-)

Sakara Drinker · 09-07-2008, 04:58 PM

no row at all but I wondered where that nugget came from. Diving with trimix doesn't enter into it as it is the partial pressure of N2 thats the factor, and helium just offsets the N2 so you can go deeper without absorbing as much N2.
I know some people that feel badly narked at 20m so everyone is different so I don't think you can say that everyone is suffering some kind of narcosis at 30m. There are lots of other factors to take into consideration. 30m in the cold, wearing several layers and a drysuit with very low vis is a lot different to warm water a shorty and crystal clear water. Metabolism, work rate, breathing rate are all factors as to how much N2 is taken on board at any given depth. There is also a school of thought that continued exposure to higher partial pressures of N2 can lessen the effects. For someone who is diving twice a day or more as a job then I think it quite possible that they don't have any effects due to a build up of tollerance. All I am trying to say is that everyone is different.

divingdoc1 · 09-07-2008, 05:20 PM

yeah i agree, i think we are all trying to say the same thing in different ways. IMHO i think that everybody is narked to some extent at 30m, just some people are better at noticing than others.

I am not sure about building up a tolerance, maybe it would be better to say you recognise the symptoms better and are able to control?, not sure thats the word im looking for, the effects better?