UK wreck death

[Braunbehrens]

I think some of this is really bad advice.

gaschef once bubbled...
There used to be a saying of "plan the dive" then "dive the plan"

Unfortunatly many divers do not plan the dive properly, working out O2 % and PO2 for the dive and deco is only a small part of the dive plan. I wonder how many "tek" divers actually produce a comprehensive dive plan with scenarios for a shortened abort dive, the planned dive, and an overstay contingency.

Contingency planning in that sense is not necessary if you know how to figure the deco on the fly. This is much safer, since we can account for ANY dive, as long as we have enough gas to do the deco.

As for planning, of course we plan the dive, down to what we eat. Yes, you read right, diet and hydration are an important part of dive planning

How much consideration is given to the introduction of modifiers into the equation if the dive is going to be stressful, cold, or just plain hard work. forget these at your peril.

I wouldn't know around here that applies to every dive.

Oxygen toxicity has been seen fairly regulary, in commercial divers at 1.2 Bar PO2.

I know an awful lot of nitrox divers who would be dead by now if that were such a a "regular" problem.

How many "Tekkies" work out there Whole Body Toxicity, this includes all air dives done in the past few days, remember Whole Body Toxicity starts at PO2 above 0.5 Bar plus time. A 15 MSW air dive and the clock is ticking, again forget these dives at your peril.

This is not an issue with the kind of diving we do.

Gas switching is another problem area, remember on diver at a time switches, and then wait for a while to see if there are any problems, before the other diver switches. If you both switch at the same time and you both have a problem, who is going to sort it out

Switching only take a few seconds. If there is a problem, go to backgas and sort it out.

Mark regulators clearly with the mix provided by that unit. American Nitrox Divers INternational, produce marker tags that fix onto the regulator hose and will show both the diver and buddy what mix is being used.

This is a super dangerous crutch. Mark your TANKS not your regulators. Check the TANK before you breathe it. Marking the regulator is asking for an O2 hit. In fact, we purposely do NOT mark the regulator and switch them around. I don't ever want to be thinking "oh yeah, that green reg is the one with the O2."

CHECK THE BOTTLE BEFORE YOU BREATHE IT.

Finally O2 analysers is yours accurate, when did you last change the fuel cell, If you are not sure or your analyser get it checked out, there is no point in trying to get gas to plus or minus 1% when your analyser cannot perform to this level.

If you are trying to get your gas to plus or minus 1% then you are doing something wrong. Nothing in diving is that accurate, unless you are going really really deep, and using something like 5% oxygen. The analyser should always be calibrated before it's used. In any case the analyser doesn't tell you what mix is in your tanks. You KNOW what mix is in your tanks, and the analyser CONFIRMS it. If it doesn't, then either the analyser is wrong, or your mix is wrong, in any case you have some work to do.

Any body has any problems, or would like to discuss this further

Email me

Tim "gaschef" Stevens

ANDI Extended Range Instructor Trainer IT#30

Better to keep it out in the open...

 

[Doppler]

Braunbehrens once bubbled...


SOME GOOD STUFF SNIPPED

Mark your TANKS not your regulators. Check the TANK before you breathe it. Marking the regulator is asking for an O2 hit. In fact, we purposely do NOT mark the regulator and switch them around. I don't ever want to be thinking "oh yeah, that green reg is the one with the O2."

CHECK THE BOTTLE BEFORE YOU BREATHE IT.

I just knew this might happen... Braunbehrens, you've hit the nail on the head!

NEVER breath anything unless you first check the bottle for the MOD and until your buddy agrees with your decision to switch gases.

 

[Genesis]

NEVER assume that everything is ok if you are doing analysis and its off.

Its NOT ok.

Either you mixed it wrong or your analyzer is broken (fuel cell worn out, etc)

The analyzer is CONFIRMATION that you did it right. It is a VERIFICATION tool.

If I take a tank with a known quantity of some %O2 gas, put in a certain amount of additional O2, then put in an amount of air, I have already computed what the mix should be. Likewise, if I stick in a certain amount of He, and a certain amount of O2, and a certain amount of air as a top, I KNOW what should be in there. If I can't measure the He directly, I can certainly infer what HAS to be He from the pressure I put in there; again, I know what it should be.

If it does NOT verify as that, within a couple of tenths of a percent for the O2, SOMETHING IS WRONG (the He is not as critical as the O2 level.) If I cannot figure out WHAT is wrong then I dump the tank and do it again. If I STILL can't figure out what is wrong then I better start checking ALL of my instrumentation (starting with but not limited to the analyzer), because something has gone badly wrong.

 

[Braunbehrens]

Genesis once bubbled...
NEVER assume that everything is ok if you are doing analysis and its off.

Its NOT ok.

Either you mixed it wrong or your analyzer is broken (fuel cell worn out, etc)

The analyzer is CONFIRMATION that you did it right. It is a VERIFICATION tool.

If I take a tank with a known quantity of some %O2 gas, put in a certain amount of additional O2, then put in an amount of air, I have already computed what the mix should be. Likewise, if I stick in a certain amount of He, and a certain amount of O2, and a certain amount of air as a top, I KNOW what should be in there. If I can't measure the He directly, I can certainly infer what HAS to be He from the pressure I put in there; again, I know what it should be.

If it does NOT verify as that, within a couple of tenths of a percent for the O2, SOMETHING IS WRONG (the He is not as critical as the O2 level.) If I cannot figure out WHAT is wrong then I dump the tank and do it again. If I STILL can't figure out what is wrong then I better start checking ALL of my instrumentation (starting with but not limited to the analyzer), because something has gone badly wrong.

Exactly. And the penalty for NOT doing this is death. Sooner or later. OxTox is no joke.