Trimix and FFMs.

[diverbrian]

I should explain as I see your points. I am being taught in the way that you suggest. Big MOD stickers on the tank and VERIFY the mix before doing the switch. It came up because my normal dive buddy is not a tech diver. She was asking about using comms when she heard that I was taking Normoxic Trimix. (Something about feeling that I am a lunatic for doing that much deco, LOL). She also said something about tying a rope to my butt so that she could haul me up and beat me when I passed out at depth.

My Normoxic instructor is obviously trying to prep us for the next course as we will be using two stage bottles. We won't be switching to the EAN36 as "travel gas", but we will be using using it on the Ascent.

Personally agree with you about the gas block switches. I don't know as if I would trust that gear either. I just like to see good points brought out for discussion.

As to the wrecks that you refer to, I will be diving some of those this summer. I am looking forward to it.

 

[Finless]

Thanks for the replies - some good points and food for thought.

I currently am only planning to use a normoxic mix (so no diff from my current use of 2 gasses) as I find 40 mtr dives in the English Channel with the sometimes (usually) dark conditions and poor vis (can be very good in the summer though!) increase the effect of my narcosis.

There are some wrecks in the "up to 60ish mtr" zone that I would like to visit. I'm not sure if I have the "right stuff" for deeper but won't know till I get over the normoxic step. I have done 60 mtrs in the Med with no problem (clear vis with light makes a big diff) and a 48 mtr Channel dive on a normoxic mix - what a difference the mix made - I could actually remember the dive properly afterwards!

It appears (in the UK at least) that the popular route is to do the full blown trimix course as it is much cheaper than doing the normoxic course and then the trimix course.

I really like my FFM for comfort and ox tox security (and warmth in the winter).....oh and pollution concerns .......

My potential continued use of my FFM if I do the trimix course was based on a 3 mix dive. Start dive breathing travel gas with bottom gas already connected. That covers most of the dive. On the ascent at a deep stop I could disconnect the bottom gas whilst breathing the travel gas and plug in the deco gas. Never without gas to breath with only one "hose change" to make. Well, that was what I thought but maybe not quite so simple in reality if more than 2 stages.

I suppose, on the plus side, there is always the fact that with my "proposed method" I can be certain that the reg on the gas switches will definitely be working. For those of us with "lazy jaws" it is nice not having to bite on a reg for over an hour.

I can now see the reason for doing the course in the normal fashion first and deciding afterwards if using the FFM can be done safely.