How to get cert on 50-100% without doing deco/deep dive??

[eponym]

One of my thoughts is also to use 2 computers. One set on air, and one that will have the settings for the gas in question. That way I can dive the profile of the "aircomputer" with the most conservative bottomtimes, and keep a good eye on O2load on the computer that has the gasmix plugged in. (This is just an idea, and I welcome any comments on it)

There are recreational dive computers which allow you to switch gasses underwater. The Suunto Vytec is one I know well, although it's no longer made. I assume there are others.

Underwater, you can let the Vytec know when you switch from your primary mix to a second (or even a third) mix. That would allow you to do what you're proposing with just one dive computer.

-Bryan

 

[Imla]

Eponym... Yes.. it would.. However it would also give me the benefit of more bottomtime
The reason for using two, is to dive on "airtime" while keeping track of o2ballast.

 

[GrimSleeper]

So it turns out I was 'presumpting' after all...

Imla, if you're reasonably 'happy' with the probability that your dive profile is a likely cause for your hit, then please consider the shouty block capitals in my first post withdrawn. I assumed PFO had been raised because there was no more obvious cause. Guess it's true what they say about assumptions.

When I started diving again after I got (badly) bent for no obvious reason, I took the route you're looking at. My first dive was to 5m on O2, then I did some dives on 50%, then I did some diving on 32% with oxygen for safety stops... Looking back, it made me feel better about the risk but it was overkill. Nowadays for recreational dives I just use 30% on air profiles, with a minimum SI of 90 minutes. Stick within MODs and there's no real need to worry about O2 exposure if you're doing a couple of recreational dives a day, but you can always either use two computers (one on air, one set to the gas you're using) or you can use oxygen exposure tables to satisfy yourself that you aren't pushing the limits.

As an exercise, maybe get a friend to dive with two computers, one on air and one on 32%, and have them write down the NDLs each gives at different points in the dive. You'll be amazed at how much further from the curve even a blend as 'light' as 32% will take you.

 

[SkimFisher]

As has already been said, carrying around O2 will not protect you from bubbles. While you may not have an interest in a Deco Procedures course, understanding the forces at work in bubble formation would be invaluable to someone in your shoes. Good reading for any diver is Mark Powell's "Deco for Divers". It does a great job explaining many of the white-papers you'd probably have to read in a deco course (at least I did, anyways).

Regardless, go get checked. Don't just assume you have a PFO.

 

[vladimir]

Regardless, go get checked. Don't just assume you have a PFO.

Why not? What's the downside to that? The OP has stated that she is unwilling to give up diving:

In my case, my life before diving was quite influenced by up and down depression. I have not been more stable, more happy, and calmer since I started diving, and I will do just about anything to continue.... M life WITH diving is just SO much better than without... so I am willing to accept that the risk of DCS is 5 times bigger. (From 1/10000 to 1/2000 or so..)​

She is also pretty happy to dive conservatively, it seems, based on this:

(I take photos, and really enjoy the 25-5m range)​

and based on her effort here to introduce extra measures of conservatism. So, keeping in mind that there might be some small risk associated with the test, why not just assume she has a PFO and dive accordingly?

 

[wedivebc]

Eponym... Yes.. it would.. However it would also give me the benefit of more bottomtime
The reason for using two, is to dive on "airtime" while keeping track of o2ballast.

Actually if you are taking advantage of the enriched gas to increase your bottom time you are negating the increased conservatism that you are hoping to gain by carrying the gas.

 

[Imla]

SKimfisher... I Am interested in the "Deco-knowledge".. just not the deep/deco dives that follows.

GrimSleeper, Yes, I do believe that a likely cause for the hit was the profile in combo with the infection/abtreatment. (Next infection, I must remember NOT to get antibiotics... )

Vladimir: That sounds about right. Unless i absomoF***lutely have to give up.. I will not do it...THat still does not mean that I like that the risks are increased, and hence, want to at least try to keep it in check.

Wedivebc... Exactly for that point, I would carry 2 computers. One to give me nodecotime as if I were diving air, and the other as a backup concerning the oksygenload of the gas. The computer limiting the dive would be the one on air, and hence I would gain the extra margins.

 

[Agility]

You might want to have a look at the Oceanic Veo 2.0 Computer, which has a function to calculate the NDL for air (79% Nitrogen) and at the same time track O2 as if it were 50%.

 

[boulderjohn]

There are recreational dive computers which allow you to switch gasses underwater. The Suunto Vytec is one I know well, although it's no longer made. I assume there are others.

There are many.

 

[SkimFisher]

I

Why not? What's the downside to that? The OP has stated that she is unwilling to give up diving:


She is also pretty happy to dive conservatively, it seems, based on this:

and based on her effort here to introduce extra measures of conservatism. So, keeping in mind that there might be some small risk associated with the test, why not just assume she has a PFO and dive accordingly?

That would be my personal preference. I don't see the harm in getting checked.

A PFO is being assumed. In all likelihood, given the statistics the OP may have a PFO, but a bad profile is a bad profile. In four pages worth of posts I see very little discussion on the profile for the bends-inducing dive.