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John Yaskowich
06-06-2009, 09:15
I have a Mares M2 and use the IRIS 2.3 software to download the information. Last weekend I did my AOW and the profile for the deep dive includes a horizontal dotted line at about 35-40 feet. It is not present in any of the other profiles.
If it is relevent the information about the dive is:
Nitrox 32%
Max depth 101 ft
Fresh water
Min water temp 54F
Dive time 28 mins

Any ideas what that line is trying to tell me?

navyhmc
06-06-2009, 09:59
What does your software say about that, I'm sure it has something to go on. I don't think it's off gassing, as that should start about 65' I think.

John Yaskowich
06-06-2009, 16:24
What does your software say about that, I'm sure it has something to go on. I don't think it's off gassing, as that should start about 65' I think.

RTFM! or in this case, the Help File.
"In the case of Nitrox dives, a red dotted line appears which indicates the maximum permitted depth at which the PO2 alarm is triggered."
Since I have not yet had a Nitrox course, I am still not sure what it means. Any nitrox divers want to put that in words of one sylable or less?

Heavy D
06-06-2009, 16:25
Maybe it's just a reference line for a safety stop or something. Who knows???

JCAT
06-06-2009, 17:08
I have a Mares M2 and use the IRIS 2.3 software to download the information. Last weekend I did my AOW and the profile for the deep dive includes a horizontal dotted line at about 35-40 feet. It is not present in any of the other profiles.
If it is relevent the information about the dive is:
Nitrox 32%
Max depth 101 ft
Fresh water
Min water temp 54F
Dive time 28 mins

Any ideas what that line is trying to tell me?

Were you diving Nitrox or Air? Since you stated you had not had a Nitrox course, I'm assuming you had your computer set to nitrox 32% by accident. Should be set to air.

Then again, if you were diving Nitrox 32, your pushing the limits IMHO.

IndyDiver
06-06-2009, 17:57
RTFM! or in this case, the Help File.
"In the case of Nitrox dives, a red dotted line appears which indicates the maximum permitted depth at which the PO2 alarm is triggered."
Since I have not yet had a Nitrox course, I am still not sure what it means. Any nitrox divers want to put that in words of one sylable or less?

The PO2 alarm goes off when the partial pressure of the oxygen exceeds a certain amount. If the total amount of oxygen in your breathing gas exceeds a certain amount (as measured by partial pressure relative to 1 ATA) - you suffer oxygen toxicity, go into convulsions, and if you are at depth at the time are 99% certain to die.

The max PO2 recommended depends on certification agency, but is either 1.2 or 1.4 depending on the agency. It is generally agreed that any PO2 over 1.6 is extremely dangerous and can result in oxygen toxicity in a matter of minutes. At 101 feet your PO2 was 1.3 and you were only 9 feet away from exceeding the recommended max of 1.4

Most computers come with the default PO2 alarm set to 1.2, so you most likely set off the alarm on your computer.

I agree with JCAT though, you are pushing the limits diving EAN32 Nitrox with no training. You were less than 10 feet from the recommended MOD for your back gas and didn't know it.

John Yaskowich
06-06-2009, 19:53
I have a Mares M2 and use the IRIS 2.3 software to download the information. Last weekend I did my AOW and the profile for the deep dive includes a horizontal dotted line at about 35-40 feet. It is not present in any of the other profiles.
If it is relevent the information about the dive is:
Nitrox 32%
Max depth 101 ft
Fresh water
Min water temp 54F
Dive time 28 mins

Any ideas what that line is trying to tell me?

Were you diving Nitrox or Air? Since you stated you had not had a Nitrox course, I'm assuming you had your computer set to nitrox 32% by accident. Should be set to air.

Then again, if you were diving Nitrox 32, your pushing the limits IMHO.

Yes, the tank was filled with 32% nitrox and the computer was set appropriately. This was part of the AOW course so the instructor and/or DM was right beside us while at depth. This is definitely something I will have to ask about when I take Nitrox (hopefully in 2 weeks).

So if the max depth was about 110 ft, why is the line on the download graph at about 45ft? Looks like I need more time in the Help file and that course so I can understand how close I was to being in trouble.

IndyDiver
06-06-2009, 19:59
The line being at 45 feet makes no sense at all. The PO2 at 45 feet is about 0.7

I have never seen a dive computer that lets you set the alarm below 1.0, and a lot of them have 1.2 thru 1.6 as possible alarm values. (of course, I've mever used a Mares computer either)

I think you need to read the help file for some other meaning meaning for the line.

JCAT
06-07-2009, 04:16
I have a Mares M2 and use the IRIS 2.3 software to download the information. Last weekend I did my AOW and the profile for the deep dive includes a horizontal dotted line at about 35-40 feet. It is not present in any of the other profiles.
If it is relevent the information about the dive is:
Nitrox 32%
Max depth 101 ft
Fresh water
Min water temp 54F
Dive time 28 mins

Any ideas what that line is trying to tell me?

Were you diving Nitrox or Air? Since you stated you had not had a Nitrox course, I'm assuming you had your computer set to nitrox 32% by accident. Should be set to air.

Then again, if you were diving Nitrox 32, your pushing the limits IMHO.

Yes, the tank was filled with 32% nitrox and the computer was set appropriately. This was part of the AOW course so the instructor and/or DM was right beside us while at depth. This is definitely something I will have to ask about when I take Nitrox (hopefully in 2 weeks).

So if the max depth was about 110 ft, why is the line on the download graph at about 45ft? Looks like I need more time in the Help file and that course so I can understand how close I was to being in trouble.

Sorry, I just assumed, my mistake. I will see what I can find out using the software. Just download it and have not had a chance to look at it.

cheers