Mixed O2?

[scubadogg]

Here is a question I'll throw out for discussion.

Headed to Truk in a couple of months and would like to dive (when applicable) with the following mix. Please add your thoughts so that I may have more to consider.

Most dives will be deep 90-160ft and I would like to extend bottom times as much as possible and understand the risk associated with decompression dives.

I would like to use Nitrox 28-32% for most dives. This will be the gas in my primary tank.

Would like to use Nitrox 40% in my 19cu. pony for a backup and deco.

My plan is to dive whatever plan I choose using the gas in the primary tank, then switch to the pony with Nitrox 40% around 60ft and ride that mix up until I surface or run out (and then switch back to the primary or use the mix on the deco bar).

If I need to bail out at depth I figure I'll have several minutes before ox-tox at depth and could get above 90ft relatively easily and ride the pony up to the deco bar (with appropiate stops of course).

I am trying to achomplish having a redundant supply and utilizing that supply to my advantage when it is not needed for emergency purposes. This is a week long trip on the Odessey and I figure as soon as I can go to 40% the better.

So what problems do you see with this? Let's not bring up entanglements or entrapments as I am aware of that risk.

Thanks in advance!

 

[Bobby]

There are so many things wrong with this dive plan I will not even try to sort it out. You need to either not troll or get much needed training. Spend some time on this board and check out old posts, you may want to start in the technical section. If you are serious about this dive plan you can pm me and I will further discuss why it is not the best idea.

Bobby

 

[scubadogg]

So should I just put whatever mix that is in my primary into the pony and call it good?

 

[Gary D.]

There are so many things wrong with this dive plan I will not even try to sort it out. You need to either not troll or get much needed training. Spend some time on this board and check out old posts, you may want to start in the technical section. If you are serious about this dive plan you can pm me and I will further discuss why it is not the best idea.

Bobby

I'll second that!

Gary D.

 

[Xman]

What problems do we see with it? I don't see anything much right with it.
Firstly, you would be better off posting this in the technical forum.
40% is hardly going to give you a large enough pp differential to be effective deco, and a pony of "deco gas" is not redundancy.
If you want redundancy then you need to dive manifolded or independent doubles of your bottom gas.
You don't seem to be taking the ox tox risk seriously of having to breathe 40% at 160ft. At this depth that would be a ppO2 of about 2.8 If you can't see what is wrong with this, then I suggest you get the necessary training to more fully understand the risks, and to enable you to use a real deco gas (100%O2).

Having said all of this. I will give you the benefit of the doubt that you are asking a serious question and not just trolling. I would suggest that if you are going to use what you have, then you should stay weel clear of any NDLs and dive with 32% in both your main cylinder and your pony for the shallower dives, and air in both for the deeper dives. This then at least gives you a little redundancy (although your pony is not really big enough for the task), and avoids putting yourself at extra risk for no reason. I wouldn't recommend diving to 160ft on air, or without proper redundancy/training though (you may already have this training, but it sounds like you don't).
Hope you take on board the reality of the risks you are planning on taking and reevaluate your plan.
Hope you have a fantastic time at Truk.

 

[Squalus]

So should I just put whatever mix that is in my primary into the pony and call it good?

Try and clear your ears fella, listen to what Bobby already told you. What type of gear do you have anyway, new or used? Make sure you have some sort of dive insurance, and the will is updated if you plan to make that dive you stated.

 

[Kriterian]

So should I just put whatever mix that is in my primary into the pony and call it good?

Can I have your stuff?

<translation: Please don't feed the trolls...especially the ones that don't even make an effort to be half-way believable>

Atleast Bobby covered his bases and was trying to be a nice guy, hehe.

 

[Don Burke]

Here is a question I'll throw out for discussion.

(snip)

So what problems do you see with this? Let's not bring up entanglements or entrapments as I am aware of that risk.

How will this kill thee?

Let me count the ways...

- Insufficient redundancy for the depth

- Insufficient decompression gas

- Excessive depth for planned bailout gasses

Hmmmm... I will let it go at that for now.

Perhaps you should trash your current plan and start over.

Doubles and a decent sized deco bottle would be a good start.

 

[MikeFerrara]

Bobby F is right on but just to give you an idea (and without too much explaination)

For a typical 160 ft wreck dive my bottom gas preference would be 18/45 in a set of doubles. For decompression I would usually use two decompression gasses...a bottle of 50% and one of O2.

My pony lives in my barn and my deco gas isn't for bailout at depth. For bailout I have my backup reg, manifold and one or more buddies.

 

[jagfish]

OK guys, I think he should understand the point by now...

Training required for these dives...

PM sent, ScubaDog...