The New Dive Rite Optima CM - My 30 Hour Review

[jale]

Unlike some posters, blinded by their own ego, think, using front CCR with double BM is used regularly in Europe...

 

[rddvet]

Unlike some posters, blinded by their own ego, think, using front CCR with double BM is used regularly in Europe...

Yeah I’m surprised by the comments against mixing it with bm doubles. I saw quite a few people diving chest mounted units with bm 12 liters at Resel in the lot. It seems like a viable combo like diving a sidekick with bm doubles.

 

[stuartv]

appreciate the response. I'll assume petrel as the controller, but ill stop asking for free game. Mainly looking for feedback on useability of the nerd controller before placing my order. Have an older nerd and love it, but havent had any experience using it as a controller.

It seems like using a NERD as a controller could be a problem if you ever needed to go on bailout and then wanted to go back on the loop. Unless, I guess, if you have a BOV and have everything set up to plumb into that as you are ascending and doing gas switches. Maybe.

I don’t know. I’m not that experienced and I don’t have mine setup that way. My NERD is strictly a monitor.

 

[Caveeagle]

I wonder what your maintenance looks like. You shouldn’t be having cells drop out with proper maintenance and good cells. Granted, when I was using Maxtec cells, they were failing left and right. But I quit using those back in the rEvo days.

First time this happened was at roughly 40hr on new unit/ new AI cells second dive of cave cross over. Fresh water only, air dry after every dive stored inside my house.

second time this happened was right after its first annual service. (2nd dive actually)..

so I don’t really see how it could be some maintenance issue on my end.

so are you saying they you have never had a (non maxtec) call fail on your O2ptima, in 1k hrs? I have discussed this with Jarrod, and Jefferson, and had just chalked this up to typical CCR bs. Maybe I should push the issue harder. I had suspected a possible bad cell harness.

 

[Superlyte27]

Yeah I’m surprised by the comments against mixing it with bm doubles. I saw quite a few people diving chest mounted units with bm 12 liters at Resel in the lot. It seems like a viable combo like diving a sidekick with bm doubles.

Must be a European thing. Never seen it here in the most dived cave in the world.

But why would you? Now you have 8" on your back and 4+" on your chest. You just made your size considerably thicker. That certainly isn't going to get you in smaller areas. I think it seriously defeats the purpose.

 

[Superlyte27]

First time this happened was at roughly 40hr on new unit/ new AI cells second dive of cave cross over. Fresh water only, air dry after every dive stored inside my house.

second time this happened was right after its first annual service. (2nd dive actually)..

so I don’t really see how it could be some maintenance issue on my end.

so are you saying they you have never had a (non maxtec) call fail on your O2ptima, in 1k hrs? I have discussed this with Jarrod, and Jefferson, and had just chalked this up to typical CCR bs. Maybe I should push the issue harder. I had suspected a possible bad cell harness.

Are you going inverted Tom Cruise style? Do you have loose lips and more moisture in the loop. Are you cold or warm water? The only reason this should happen is if cells get wet. So why are your cells getting wet? Or a bad wire. But that's inspected as part of your build checklist.

 

[Caveeagle]

Are you going inverted Tom Cruise style? Do you have loose lips and more moisture in the loop. Are you cold or warm water? The only reason this should happen is if cells get wet. So why are your cells getting wet? Or a bad wire. But that's inspected as part of your build checklist.

you may have hit the nail on the head. During my cave/CCR cross over, I thought I might be getting some water in, but could never pinpoint any source. It was never more than a couple table spoons, that for past the traps. But I did have a couple dives where my EAC was dripping water post dive.

then after my first annual service, I found a pinhole leak in the mouthpiece. But that doesn’t explain how it got past the traps.

..and no underwater hanging, dangling, or crazy Ivans!

last few dives have been dry and trouble free, so hopefully it’s all sorted out.

 

[rddvet]

Must be a European thing. Never seen it here in the most dived cave in the world.

But why would you? Now you have 8" on your back and 4+" on your chest. You just made your size considerably thicker. That certainly isn't going to get you in smaller areas. I think it seriously defeats the purpose.

it’s definitely for big power cave. At that time (6-7 years ago) my wife and I were the weirdos diving side mount in the Lot. Sm wasn’t popular but cm rebreathers with bm doubles was. A lot of guys in that area love their doubles over anything sm.

 

[Superlyte27]

you may have hit the nail on the head. During my cave/CCR cross over, I thought I might be getting some water in, but could never pinpoint any source. It was never more than a couple table spoons, that for past the traps. But I did have a couple dives where my EAC was dripping water post dive.

then after my first annual service, I found a pinhole leak in the mouthpiece. But that doesn’t explain how it got past the traps.

..and no underwater hanging, dangling, or crazy Ivans!

last few dives have been dry and trouble free, so hopefully it’s all sorted out.

"Crazy Ivans" made me laugh out loud.

 

[uwxplorer]

So, to answer my own questions about how much bailout you need for a 4 hour dive at 100’ in open water, let’s do a bit of math off the cuff.

I’m going to guess at some of the numbers, but they’ll be close. You can verify them if you want. But at 4 hours at 100’ puts your deco at just under 90 minutes. Your first stop is at 50’ I think. It might be 60. But I’m pretty sure it’s 50. I’m going by memory. Granted, this is a dive on air at 1.2ppO2.

So, 90 minutes, with less than 15 of it being between 50’ and 20’ I’ll do this gas on 32% Bailout. At 20’ I’ll switch to Oxygen. So, 15 minutes on 32%. That’s an AL40. And 75 minutes on Oxygen, that’s also an AL40 of O2.

So, a 4 hour dive with a 1.2 set point with just two AL40’s for bailout/deco, in open water.

Anyway, this is pretty close based on a 4 hour dive we used to do a lot.

Please print a plan to back this up. I can't get even remotely close from this with my GF 50/80 setting on Multideco.