The New Dive Rite Optima CM - My 30 Hour Review

[Aquanomad]

My last dive on the CM. CO2 not an issue

IMG_20200313_135743

• Superlyte27
• Mar 29, 2020

Bonaire 2020

Curious what the objective for the bounce to 483' was? Something cool you had to lay eyes on, pushing the CM through the paces, or???

 

[rjack321]

You are quoting me, not stuartv.

It don’t see how it matters that the scrubber is a “rigid volume”. What matters is how far the gas has to travel away from the lungs, and where that farthest point is is in relation to the surface. Gas always wants to find a way to the surface/up. Whether the gas is inside plastic, rubber or ballistic nylon, when it’s in the loop, it’s subject to ambient pressure and the physics that go with it.

no that's not how it works.

If you have a rigid volume you can put that as deep as you want and its not relevant. Imagine a pipe traveling down from the surface of a pool to a drum at 6ft depth then coming back up your DSV at the surface - that whole system has no additional WOB compared to the same pipes laying out in your yard.

The position of the flexible bits - in this case the counterlungs - is what dictates the hydrostatic load.

 

[uwxplorer]

All that, backed by DiveRite's stellar customer service with a price tag under $6k

And you're going to be an instructor on it... We get it.
Just wait for Brad Horn's perennial questions in 1, 2, 3...

 

[silent running]

no that's not how it works.

If you have a rigid volume you can put that as deep as you want and its not relevant. Imagine a pipe traveling down from the surface of a pool to a drum at 6ft depth then coming back up your DSV at the surface - that whole system has no additional WOB compared to the same pipes laying out in your yard.

The position of the flexible bits - in this case the counterlungs - is what dictates the hydrostatic load.

“imagine a pipe traveling down from the surface”?

But “the pipe” is not traveling down from the surface. In this case, “the pipe” is the scrubber, which is connected to the flexible counter lungs which will almost always be above the “rigid volume” of the scrubber, and still in the water column at whatever ambient pressure the diver is...

 

[Superlyte27]

Curious what the objective for the bounce to 483' was? Something cool you had to lay eyes on, pushing the CM through the paces, or???

Yeah, there was a time years ago that people said the Optima couldn't be a technical rebreather because of hammerhead electronics and cartridge scrubber, despite the rumors that Paul H. had done a nearly 500' dive at almost 10 hours with one over a decade ago.

I didn't want people claiming the same of this. I've spent quite a bit of time with it in a cave and very deep. It definitely works as a technical rebreather. Funny thing is, Paul asked me why I went to 500' on it and I said, "because you did". He said that was a rumor. He only went to 407' on it. Lol.

 

[Superlyte27]

And you're going to be an instructor on it... We get it.
Just wait for Brad Horn's perennial questions in 1, 2, 3...

I don't care about teaching. I'll do it for family, friends and excellent divers or super excellent people, but I'm bordering on wealthy now. It's not worth it to me to tolerate goobers. It doesn't matter to me whether you take a class or not. But credit where credit is due, this unit is awesome. If you don't believe me, you can come try mine for free.

 

[rjack321]

Curious what the objective for the bounce to 483' was? Something cool you had to lay eyes on, pushing the CM through the paces, or???

That's the UDIE standard CCR cross-over depth

 

[scubadada]

...I assembled on 620 and one 260 onto the same Mk 25, so they would have exactly the same IP feeding them both. I used the stock hoses that came on both, so that each 2nd had the same exact hose feeding it.

I dived it like that. To me, I could feel a slight difference between the two - the G260 breathed just a little bit nicer than the S620Ti. I let a friend dive that reg set and she concluded the same thing...

Hi Stuart,

I was just wondering about the depths and RMVs for these test dives. It has always been my impression that on relatively shallow dives and/or with normal/regular RMVs, that all regulators would generally perform OK, without major differences.

Deeper depths and higher RMVs might bring out some differences between regs. On several occasions, with serious exertion, I have pushed very good regs to the point where the WOB, particularly on exhalation, was noticeable. Perhaps you have done this also.

Of course, there are other characteristics, other than WOB, that might lead one to prefer one reg over another.

Very best and good diving, Craig

 

[cathal]

But credit where credit is due, this unit is awesome. If you don't believe me, you can come try mine for free.

I don't think anyone questions your ability on appraising how this unit performs at depth, or in comparing its WOB with the WOB of other units. I think what others are trying to point out is that at present there is a lack of any independent testing of the WOB of this unit to ensure it meets the minimum performance envelopes as determined by the relevant test standard e.g. EN 14143. This is important information. Until it passes, we simply do not know how this thing breathes at depth.

After passing one of these test standards then its industry actors like yourself who can provide invaluable nuanced analysis of comparing its WOB against the other units on the market. But until it can do this, its WOB performance is simply unknown as a life safety system and unfortunately it also quite rightly precludes it from being sold in some markets.

 

[stuartv]

Hi Stuart,

I was just wondering about the depths and RMVs for these test dives. It has always been my impression that on relatively shallow dives and/or with normal/regular RMVs, that all regulators would generally perform OK, without major differences.

Deeper depths and higher RMVs might bring out some differences between regs. On several occasions, with serious exertion, I have pushed very good regs to the point where the WOB, particularly on exhalation, was noticeable. Perhaps you have done this also.

Of course, there are other characteristics, other than WOB, that might lead one to prefer one reg over another.

Very best and good diving, Craig

Test dives as deep as 110' or so. But, normal, relaxed RMVs...

I suppose it could be the case that an S620Ti would not breathe as nicely at a normal RMV, but overtake and surpass a G260 when the RMV goes up to an equivalent of major exertion at some significant depth. However, I personally am perfectly content to stipulate that as a possibility and still stick with the G260s...

Oh, and no, the only time I ever felt like I was really pushing a reg was trying to keep up with my deep/wreck instructor, on the bottom of the local quarry that was around 40 degrees. It did not take long for that reg to freeze and start to freeflow, so I still did not have the experience of noticing a feeling of increased WOB.