advice on Deep diving, please

[davis]

I have 110 dives logged, half to around 30 m, I also have a basic Nitrox card. I now want to dive a wreck which lies at 40m. I would appreciate some advice on planning this dive, so all views positive or negative are welcome . Should I dive on air and trust my computer ? or Nitrox ( which I find hard to get a fill locally) . If on air , how long down so as not to have too long deco. Should I do a deep course first before I drop to this depth? Thanks in advance.

[Captain Deco]

Now that you are starting to ask these questions, I can only tell you that from my point of view (and it is only an opinion) that the best thing you can do is take some training from a dive professional.

In my view, use Nitrox, and gain the benefits of enriched oxygen - clearer head, more bottom time etc. If this is a diving plan that you intend to follow often, then do an advance Nitrox course. The benefits are many, and the diving will only ever get deeper as you progress!!!

The risk of diving on air is that you remember less and less of the dive the deeper you go on air. I did a 45-50m dive on air, and recall bugger all other than I was there with someone.

[liamm]

If you are unsure then do the course. No stop times will be sort at that depth, even with nitrox. I would say a redundant air source is a must also.

Which wreck are you thinking of?

[mala]

its hard to give advice without knowing your set up and sac rate and the position of the wreck site etc.
air is ok for 40m but you will get deco after about 10 mins or so.
you will need to do the maths.

[Mark Chase]

Originally Posted by davis

I have 110 dives logged, half to around 30 m, I also have a basic Nitrox card. I now want to dive a wreck which lies at 40m. I would appreciate some advice on planning this dive, so all views positive or negative are welcome . Should I dive on air and trust my computer ? or Nitrox ( which I find hard to get a fill locally) . If on air , how long down so as not to have too long deco. Should I do a deep course first before I drop to this depth? Thanks in advance.

If you need to ask such broad questions then i would suggest you need professional training or at very least a mentor.

Training will allow you to get the most out of the dive

If you do not have the basic understanding of planning your deco need or your gas requirements for the dive and the deco you would be very foolish attempting it. If this is a UK dive and you have never experienced the narcosis at 40m you may be in for a shock.

110 dives is a fair number and I may be grossly underestimating your ability. If i am then I apologies but the way your question is worded it sounds like you don't know where to start with your planning.

You need the following basic information:

How deep is the actual dive? (40m may be the sea bed)

What is the best Nitrox mix for the dive? (air would give a short dive and big deco)

What is my average gas consumption?

How much gas do i have?

How much gas will i need for the dive with an adequate safety reserve?

Can i hold proper deco stops

Can i plan and run deco properly

Do i understand how to make deco safer and less demanding on my body

Do I understand the absolute minimum deco i can do in an emergency

Do I understand how best to manage my gas in an emergency

Do I have competence to properly handle a SMB and reel

Do I have adequate equipment ie redundant SMB and reel, spare mask, spare torch, multiple cutting tools

Do I have the skills to handle and manage a twinset in the event of a free flow

Ar my buddy skills good enough for me to be a benefit to my buddy on this dive


If you answered no to any of the above then get some one to teach you.

Mark Powell is my recommendation. He's on YD you will lern a lot and enjoy the course.

EDIT: Sorry just noticed your in Ireland. Ge on to Barry (Bang On) and get a recomendation from him)

Id go for TDI Advanced Nitrox and Decompression Procedures.


Personally I prefer Trimix at 40m in the UK so Id be booking my Entry Level Trimix course as well. This will depend totally on how comfortable you feel at 40m and its a very individual thing.

Alternatively there is DIRF and TECH1 but this has strings attached so do some research first.

ATB

Mark

[colinicky]

To give you an idea of times

20 minutes at 40m = total deco of 23 minutes using air .
20 minutes at 40m = total deco of 13 minutes on 28% nitrox which gives 1.4 ppo2 .

As others have said if you need to ask the question then you should do the course .As Jay has said do the advanced nitrox but do the deco procedures course as well .
then you end up with :-
20 minutes at 40m = total deco of 8 minutes using 28% nitrox & switching to 80% at 6m on ascent .

[Paul Oliver]

Some top advice from Captain Deco and Chasey, with lots of very good points, Colins simple examples here really hit the nail on the head though

Originally Posted by colinicky

To give you an idea of times

20 minutes at 40m = total deco of 23 minutes using air .
20 minutes at 40m = total deco of 13 minutes on 28% nitrox which gives 1.4 ppo2 .

As others have said if you need to ask the question then you should do the course .As Jay has said do the advanced nitrox but do the deco procedures course as well .
then you end up with :-
20 minutes at 40m = total deco of 8 minutes using 28% nitrox & switching to 80% at 6m on ascent .

[Mal Bridgeman]

Originally Posted by Mark Chase

Alternatively there is DIRF and TECH1 but this has strings attached so do some research first.

No Mark, their buoyancy control is such that they look like they are attached by strings

I was in a similar position to the OP a few years ago .... my chosen route was to go for TDI Advanced Nitrox & Deco Procs with Mark Powell, then Normoxic Trimix with Frank Bruce. Both really good instructors from whom I learned loads.

Earlier this year I did DIR-F and next year I will do Tech 1.

Either route will get you the proficiency you need to dive to 40m in the UK. What I particularly like about the DIR approach is the team diving mantra and its drive for safety through a very high standard of proficiency.

Whatever works for you, enjoy the dives.
Mal

[Adrian Kelland]

Advice? Get appropriate training from a good instructor. Shared with the people you are most likely to dive with.

Adrian

[rustferret]

Theres some very good advice here but couldn't help wondering are you a member of a club and if so is there no one there who can train you or take you under their wing?

Rustferret