Sherwood scuba, SR 2

[Shabaday]

Two different functions. I almost never change my cracking effort, except when scootering. I might use it to stop a dribble of freeflow in a reg that's tuned too light.
But I often decrease my Venturi assist, especially on my octo for giant stride. I also crack it back a little on my deep dives where increased air density makes Venturi assist a little more vigorous, unless I need the extra "oomph" in current.
If you need to hand off your octo when you've forgotten to turn the Venturi back to "Dive", it still breathes just fine. If you hand your octo with the knob cranked in to your OOA buddy, it may add to their panic because he/she may feel like they're not getting enough air, because it breathes so stiffly.
When we've dumbed down training so much that divers aren't taught the difference between the two functions, or worse - that the manufacturers successfully sell it as an "improvement", then we've gone too far.

Isn't Atomic second stages Venturi assist automatic? And for this reason you aren't as fond of Atomics seconds? When I looked at the SR2 it looked like an Atomic engineer developed it. I also set my Venturi to predive during a giant stride...and so would you say Atomics mouthpiece works sort of the same way? To help prevent a free flow?

 

[rsingler]

Yes, Atomic is automatic, and I kind of like manual adjustment. But it does address the complaint I had above, in that the Venturi assist is minimal at the surface, but that as the reg reaches 60', the vane retracts partially out of the way, improving Venturi assist. So for the diver jumping off a boat, Atomic automatically has you in Pre-Dive. Problem solved.
What I don't know is whether on deep dives (100' on air) in current, the Venturi is so vigorous that I might wish I could dial it back. Surface testing on my rotameter suggests that that might happen at even deeper depths with high gas flow, but by then I'd be on Trimix and lower gas density. I'm guessing that Atomic engineers have already figured this out, and are denying me my manual stick shift in favor of an automatic. Sigh.

 

[BoltSnap]

Isn't Atomic second stages Venturi assist automatic? And for this reason you aren't as fond of Atomics seconds? When I looked at the SR2 it looked like an Atomic engineer developed it. I also set my Venturi to predate during a giant stride...and so would you say Atomics mouthpiece works sort of the same way? To help prevent a free flow?

I'm guessing that Atomic engineers have already figured this out, and are denying me my manual stick shift in favor of an automatic.

I love automatic transmission and hate, with passion, standard/manual transmission. IMO, Atomic's AUTOMATIC FLOW CONTROL, AFC, is out of this world and the greatest thing since the invention of scuba.

 

[rsingler]

The thing I love is that floating orifice and the LP seat that lasts forever. I can live with the Venturi. But, sad to say, people have been known to disagree with me. Alas!

 

[Geo7]

Like Rsingler I like manual venturi and cracking effort control, and separate controls for the same reasons. I also love manual cars, but my next one will be auto...

When I started diving Atomics I found that they are very well dialed in, and the auto venturi does exactly what it should, and I hardly ever need to mess with it. My primary Atomic 2nd was "hacked" to stay in max venturi at all times though. The workmanship and smooth breathing had one me over.

However, I like that on my current S620ti I can open the venturi up all the way and get a more aggressive blast of air (if also set to lower than manufacturer cracking effort). This is something a minority of divers like, so for the majority the Atomic is perfect. Also, for a minority of DIY service divers the Atomic floating seat is not too important, but for most divers it is awesome.

 

[BoltSnap]

floating orifice

Is the "floating orifice" in the Sherwood SS very different from the one in the Atomic SS?

 

[rhwestfall]

NVM..

 

[rsingler]

I think it's more like the Atomic SS1 floating orifice. There's no wave spring to actually back the orifice off the LP seat. But when IP disappears, the knife edge pressure on the seat drops to zero, like the SS1.

 

[lexvil]

It’s late here but, in use I can’t tell much difference between full open and full closed while breathing from the SR, I don’t think it could do enough to instill any additional panic but it does seem to help with freeflow when the reg is facing down, the reg just seems to deliver all of the air you want whenever you want it. There are some things I would like to try once I get some spare parts and have some time.

Two different functions. I almost never change my cracking effort, except when scootering. I might use it to stop a dribble of freeflow in a reg that's tuned too light.
But I often decrease my Venturi assist, especially on my octo for giant stride. I also crack it back a little on my deep dives where increased air density makes Venturi assist a little more vigorous, unless I need the extra "oomph" in current.
If you need to hand off your octo when you've forgotten to turn the Venturi back to "Dive", it still breathes just fine. If you hand your octo with the knob cranked in to your OOA buddy, it may add to their panic because he/she may feel like they're not getting enough air, because it breathes so stiffly.
When we've dumbed down training so much that divers aren't taught the difference between the two functions, or worse - that the manufacturers successfully sell it as an "improvement", then we've gone too far.

 

[lexvil]

Final report on the SR2,
overall a pretty amazing regulator, smooth and flawless performance from the second stage, very easy breathing that is out performing my D420!

I have a hI pitch sound coming from the first stage, it seemed to come on after several dives, I reset the environmental seal with the reg pressurized and it’s better, mostly happened between 2000 and 3000 psi tank pressure, I can only hear it under water. I’m thinking it may be an interaction between the pressure transmitter against the piston head, my dilemma, send it in for a service and see if they correct it (it’s was bought new from a dealer) or open it up myself?.