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View Full Version : Sherwood Regs and "the leak"



DDGator
07-11-2007, 12:48
I recently purchased a Sherwood Brut (the new design) after using one as a rental. Seems like a great, simple regulator.
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<DIV>When under pressure, Sherwoods create a small stream of air bubbles that vent from the 1st stage. I know this is normal -- the manuals and such make that clear.</DIV>
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<DIV>Just curious -- how much air do you lose in this process? Is it even a measurable amount? What is the benefit to designing the reg this way?</DIV>
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<DIV>Any input would be appreciated -- it doesn't matter much, but I am curious!</DIV>

cummings66
07-11-2007, 12:54
Yes you can measure it, in fact one of the things done in service is to measure the amount you can collect in a certain amount of time.
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<DIV>It's not enough that "you" would notice it during diving, and you will have several people tell you that your reg is broken. I used to keep my manual with me to prove otherwise. Some DM's and Instructors used to give me grief over the bubbles.</DIV>
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<DIV>I'm not the engineer so I can't tell you why this way is better than how Apeks did their reg for example. I know my LDS says it's simple, clean and fewer things to go wrong. I don't know.</DIV>

DDGator
07-11-2007, 13:09
Thanks, guys. I assumed it mustbe insignificant or they wouldn't keep doing it. I probably will keep the tank valve closed until its getting close to "go time," just for the psychological value. :)
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<DIV>All I have read indicates that Sherwoods (and particularly the very basic Brut) are very rugged, very reliable, and very easy to service.</DIV>
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<DIV>Doing my first OW dive with the new Brut this weekend. Sat on the bottom of my pool for 20 minutes or so last weekend. ;)</DIV>

cummings66
07-11-2007, 22:18
Your reghas a reputation for being extremely tough in the proper environment. Based on your sig I'd say you've got a tough reg that will last you forever.
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<DIV>If you're curious as to how much pressure bleeds off or how much air it uses then time it the way a tech does. Take a cup with measuring lines on it and hook the reg up to a tank and get it under water. Make sure the cup is full of water and upside down and place it over the bubbles. Flip it over and start the timer. Stop it when you desire, as long as you can do the math it doesn't mater. You'll find so many CCs per hour or whatever and from that you can find out how much air it will consume.</DIV>
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<DIV>One of those plastic cough syrup cups will be fine.</DIV>

DDGator
07-11-2007, 22:24
That is an interesting idea -- I will try that when the opportunity presents and report back. Thanks.

rktman26
07-12-2007, 17:58
I never thought about the air losss on the boat ride out to the wreck.
I have a Brut, and when I set up my gear at the shop, check the BC and
regs for function, I USED TO leave the air on (so I won't forget to
turn it on before I hit the water). After reading this thread and
putting 2 and 2 together, I think I'll function check my gear, turn the
first stage OFF, and then take the boat trip out to the wreck.

ScubaToys Larry
07-12-2007, 18:08
Really, you are talking about a very insignificant amount of air, and they now have a new versions, used on some that does not constant bleed. They only bleed off the additional pressure on ascent - so sitting on the boat, descending, etc - no bubbles.

cummings66
07-12-2007, 21:44
What Larry said, it's such a small amount that you won't notice it at all. I've rigged my gear and had it set hours and had the same psi reading afterwards. It is a TINY amount that comes out if the first stage is working correctly.
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<DIV>The number and size of the bubbles may vary from regulator to regulator, but the volume of air should be 13 - 25 cc per minute and you can measure that with a graduated cylinder.</DIV>
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<DIV>However, 77.6 cf in your AL80 is 2,197,387.3 cc's. Now doing the math if you use 25 cc's per minute your tank will be empty in 847895 minutes or 14,131 hours, or 588 days. Is it really anything to worry about? Nope. More reasonably, 1 cf is 28,316.85 cc's and that takes 1132.674 minutes to get to which is 18.8779 hours or most of a day to lose 1 cf. Why bother turning off the valve for that. You risk more by forgetting to turn it back on. </DIV>
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<DIV>So Larry, how's that answer for how small it is? I think I got the math right.</DIV>

dutch552
07-13-2007, 10:14
I've had an Oasis for the last 6 years. It was my first regulator and I have had ZERO problems with it. It is a moose of a regulator that provides air reliably and eliminates dry mouth with the moisture retaining fins. You will get taps on the shoulder from concerned diving buddies and misinformed DM's that you have a first stage leak and have to go through the whole dry-bleed lecture but then you keep on diving. They're super easy to work on and my LDS only charges 30 bucks for the entire annual service, as compared to $80 for an Apeks setup. You have a reg that will outlast a lot of others with proper maintenance.

rktman26
07-13-2007, 20:41
Okay, I stand corrected. Due to the amount of effort that was put into
convincing me how insignificant the lost air is, I'll turn it on when I
set up, and leave it on until I take the reg of the tank.

Thanks for the info!!!!

cummings66
07-14-2007, 11:12
Actually it wasn't any effort, I just dug out my service manual and looked up the leak test bit and then got the calculator out and did the math. I'd never done that and had always known it was very little, what I didn't know what truely how little it is. 1 cf in 18 hours is pretty dang small, that sort of surprised me, I breathe that in 2 minutes on the surface.