Could have been, but everything turned out cool

Tom Rose · 19th June 2007, 20:54

Yesterday 9 of us played hooky and went diving off the coast of North Carolina. The trip report will be filed soon as soon as I get the pictures.

I was returning to the anchor line in about 80 feet of water on my little cressi rig. Everything was going swimmingly. I was in the grove.

The flow controller is a critical orifice with a manual bypass.

My normal practice is to heat up the mix to about just 1.6 prior to returning to the surface.

This reduces task loading as I come up because I know Mr. Boyle will take over and soon have me at somewhere below 1.6 after I have ascended to 60 feet or more and above .25 at the surface. In this case, about .4 or so even if I turn off the O2.

I hit the O2 add button and the mix went to 1.5 and the hissing stopped. I pushed the button again and nothing happened. I figured at worst case I could go to backup, so I headed up at the happy pace of 30 feet a minute and was able to finish the dive with no problem. At 30 feet I was able to send some more O2 into the bag, even though I really did not need it. Not even a rise in blood pressure.

Several lessons here. Plan for a little more O2 than you will use. I have decided to use 13 cubic foot tanks for O2 instead of 6 cubic foot ones for dives below 50 feet from now on. I theory I can use a 6 cubic foot tank for a couple of hours, but I take pictures and am up and down a lot...that uses gas.

Instead of a button gauge, a little better gauge would be helpful. I checked my whip pressure gauge and I read high. That is what caused the whole thing.

As I said in the title, I was never in trouble, and had a great dive.

Tom

divelermentov · 21st June 2007, 03:05

good to hear it worked out all well,

My original spg was reading low when i got my unit- caused no problems but some headache why i was using so much o2 - until figured out that i wasn't but the gage was reading low.

19th June 2007, 20:54	#1 (permalink)
Tom Rose Still Learning Current Rebreather/s: Other CCR Home Build Other Rebreather/s: Prism Topaz Other CCR Home Build Join Date: Oct 2005 Location: USA,North Carolina Posts: 330	Could have been, but everything turned out cool Yesterday 9 of us played hooky and went diving off the coast of North Carolina. The trip report will be filed soon as soon as I get the pictures. I was returning to the anchor line in about 80 feet of water on my little cressi rig. Everything was going swimmingly. I was in the grove. The flow controller is a critical orifice with a manual bypass. My normal practice is to heat up the mix to about just 1.6 prior to returning to the surface. This reduces task loading as I come up because I know Mr. Boyle will take over and soon have me at somewhere below 1.6 after I have ascended to 60 feet or more and above .25 at the surface. In this case, about .4 or so even if I turn off the O2. I hit the O2 add button and the mix went to 1.5 and the hissing stopped. I pushed the button again and nothing happened. I figured at worst case I could go to backup, so I headed up at the happy pace of 30 feet a minute and was able to finish the dive with no problem. At 30 feet I was able to send some more O2 into the bag, even though I really did not need it. Not even a rise in blood pressure. Several lessons here. Plan for a little more O2 than you will use. I have decided to use 13 cubic foot tanks for O2 instead of 6 cubic foot ones for dives below 50 feet from now on. I theory I can use a 6 cubic foot tank for a couple of hours, but I take pictures and am up and down a lot...that uses gas. Instead of a button gauge, a little better gauge would be helpful. I checked my whip pressure gauge and I read high. That is what caused the whole thing. As I said in the title, I was never in trouble, and had a great dive. Tom __________________ The 50-50-90 rule: Anytime I have a 50-50 chance of getting something right, there's a 90% probability I'll get it wrong the first time. www.atlimp.com
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21st June 2007, 03:05	#2 (permalink)
divelermentov Nutty dentist - uwdriller Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: Auckland Posts: 625	Re: Could have been, but everything turned out cool good to hear it worked out all well, My original spg was reading low when i got my unit- caused no problems but some headache why i was using so much o2 - until figured out that i wasn't but the gage was reading low. __________________ May The Sorb Be With You
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