multiday OTU's

[oldguy]

Any good consensus available on multi-day nitrox dives and oxtox? Depth, time, multiple dives, partial pressures, etc? Chart, table, etc. Mainly interested in single gas nitrox use. Thanks for all responses. Safe diving.

[mgersch]

I think your location says it all. (my opinion)

As you know from you nitrox course, there are simple tables available that give all this info. Each of the training agencies that offers a nitrox class has a table.

But the more, repetitive dives we do, and the more repetitive days, and the more deco we do, I think, it all begins to fall apart. (my opinion).

[Line Squirrel]

But the more, repetitive dives we do, and the more repetitive days, and the more deco we do, I think, it all begins to fall apart. (my opinion).

FWIW I think you're right, not an exact science. Way too many variables.

I'm a "one dive per day" guy but still I quit diving to 1.4ppo during the working portion a couple years ago. I try to keep it at 1.2ppo or lower.

[Mike Edmonston]

Any good consensus available on multi-day nitrox dives and oxtox? Depth, time, multiple dives, partial pressures, etc? Chart, table, etc. Mainly interested in single gas nitrox use. Thanks for all responses. Safe diving.

Something I like to do, is to reduce my daily oxygen limit by 10% for every consecutive day that I dive.

For example, if I dive on monday, and i have a clean o2 clock, then my full OTU count is available (minus the reserves for an inadvertent trip to the chamber). If I have less then 48 hours between dives (Thursday), then I reduce my allowable o2 clock by 10% for the next day (Tuesday, Wednesday etc...), and so on. I have also decided to use a running PPo2 of 1.2 instead of 1.4 during my dives.

Again, this is just what I like to do. YMMV.

Safe diving..

[contender]

Something I like to do, is to reduce my daily oxygen limit by 10% for every consecutive day that I dive.

For example, if I dive on monday, and i have a clean o2 clock, then my full OTU count is available (minus the reserves for an inadvertent trip to the chamber). If I have less then 48 hours between dives (Thursday), then I reduce my allowable o2 clock by 10% for the next day (Tuesday, Wednesday etc...), and so on. I have also decided to use a running PPo2 of 1.2 instead of 1.4 during my dives.

Again, this is just what I like to do. YMMV.

Safe diving..

I believe that the OTU's table is based on exactly half of what you can really have for that inadvertent trip to the chamber. So not sure that you need to add in a reserve for that trip. I read this in the NAUI tech EANx & deco book by Jan Neal, if you are interested in it.

Chad

[Line Squirrel]

I believe that the OTU's table is based on exactly half of what you can really have for that inadvertent trip to the chamber.
Chad

Chad - That is how I was trained as well, the OTU limits were/are based on the need for a possible trip to the chamber.

However, with a couple of unexplained deaths that are suspected oxtox, even though their gas analyzed within acceptable ppo2 limits, many of us are opting to be a little more conservative.

[contender]

Chad - That is how I was trained as well, the OTU limits were/are based on the need for a possible trip to the chamber.

However, with a couple of unexplained deaths that are suspected oxtox, even though their gas analyzed within acceptable ppo2 limits, many of us are opting to be a little more conservative.

I completely agree with being more conservative, I have lowered my ppo2 limits as well in light of recent events.

[Mike Edmonston]

I believe that the OTU's table is based on exactly half of what you can really have for that inadvertent trip to the chamber. So not sure that you need to add in a reserve for that trip. I read this in the NAUI tech EANx & deco book by Jan Neal, if you are interested in it.

Chad

Hi Chad,

That's exactly what I was referring to. I do not cut my OTU in 1/4's. Sorry I wasn't more specific. I have dove with some, that did not "reserve" any clock for a possible chamber trip, that is why I mentioned it.

BTW, that is a good book, I might have read it once or twice :smt047

Safe diving,

[Mike Edmonston]

Hey Mike,

Nice grooping on your Avatar. .223 at 100 Meters?

[Line Squirrel]

Hey Mike,

Nice grooping on your Avatar. .223 at 100 Meters?

Great guess!! 22-250 at 100yds, which is pretty much the same thing <G>

[contender]

Hi Chad,

That's exactly what I was referring to. I do not cut my OTU in 1/4's. Sorry I wasn't more specific. I have dove with some, that did not "reserve" any clock for a possible chamber trip, that is why I mentioned it.

BTW, that is a good book, I might have read it once or twice :smt047

Safe diving,

I thought that you might have read it before.:-D

[oldguy]

Thanks to all the responses. I am interested in info from the real divers who do their own numbers based on the growing technical diving data and not the tables from the basic nitrox classes. I pursue stats on all diving, gas, air, nitrox, etc. because we continue to hear about the freak accidents. I like to set my parameters a little tighter to avoid this happening to me as I continue to dive commercially (hardhat) and for sport as I get older. Nothing wrong with gathering information over my 30+ years of diving. Like target shooting, you get a pattern that works and you stay away from the fringe areas.

[Line Squirrel]

Thanks to all the responses except the barb from "mgersh". I do not know what my location has to do with this question.

I don't think he meant any harm.

I read it as he was just saying that it's not an exact science and "nobody [really] knows".

[mgersch]

Thanks to all the responses except the barb from "mgersh". I do not know what my location has to do with this question.

Your location is listed as "nobody knows"

It may not have been the most funny PUN in the world but my point was just that. That all these algorithms fall apart on multiple days of diving. Everyone on this thread has acknowledged that and that was why they reccommened increased conservatism.

Geez, talk about no sense of humor........

[oldguy]

Huh ? What ? OK, thanks.

[Randy Thornton]

Personally I don't tend to worry so much about OTUs as long as I am diving OC. When I am doing multiple day/multiple dives on CCR, I tend to track it a little more carefully. This is not to say that it is not possible to exceed your limits on OC, it's just a lot easier on CCR! I have done trips where I was doing 5 fairly deep dives per day over a 7 day period. After 7 days, I take at least one day off. Going over 300 OTUS per day is a lot of diving, and I find that I almost have to work at it to get that much especially over a multi day period.

Just my $.02 (Not worth much more than what you paid for it!)