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bversteegh
11-11-2007, 21:30
I have a Mares V16, has treated me very well. However, as a photographer, would really like to get the bubbles diverted away from the camera - more than one ruined picture with bubbles.

Are there any exhaust extensions that work? Or worst case (and a rebreater is not in the budget yet:smiley19:), any regulators that exhaust farther back?

frankc420
11-11-2007, 23:24
From what I've been told, putting any kind of exhaust extension on your reg will cause it to freeflow... maybe that's a false statement, but it's what I was told. I was looking for something to divert the bubbles away from my ears at the time.

I was thinking about sticking some high pore sponges into the exhaust holes to see if it would breakup the bubbles :P

CompuDude
11-12-2007, 12:47
The best I've seen is the one I use, but good luck getting your hands on one.

ScubaPro makes a bubble deflector for their S600 regs (it fits several other models of SP regs as well). Looks kinda scary, but there really is a big difference in bubble interference:


ScubaPro Bubble Deflector:

Scubapro engineers conceived this bubble deflector to channel all the exhaled air bubbles backwards. This extended exhaust T is favored by all underwater photographers, quiet divers and all those who must stay immobile underwater for long periods. It can be installed to R380, R390, S550, S600, G500., even underwater.
http://kalani.net/scuba/divegear/S600%20exhaust%20T.jpg

The deflector was never sold in the states, and it was discontinued some time ago, so I don't think you're likely to find one overseas, either, at this point.

Puffer Fish
11-12-2007, 14:02
There is the Kronos aqualung reg and the whole Posiedon line of regs, that don't even have that issue..

I have used both... and still miss my Posiedon.

The Kronos is a great breathing reg, but tipping your head to the right side does interesting things...none of which are good.

Although not as bad,, the same can be side of a left bend on the other reg.

NitroWill
11-12-2007, 14:05
I use a bicycle innertube connected to each side of the bubble ouputs and have holes cut in the back, it works pretty good and is only a couple bucks!

Puffer Fish
11-12-2007, 15:00
I use a bicycle innertube connected to each side of the bubble ouputs and have holes cut in the back, it works pretty good and is only a couple bucks!
Nice look I will bet. Given the positions I get myself in sometimes, I think I will stay with the side exhaust regs.

BSea
11-12-2007, 15:14
I have a Mares V16, has treated me very well. However, as a photographer, would really like to get the bubbles diverted away from the camera - more than one ruined picture with bubbles.

Are there any exhaust extensions that work? Or worst case (and a rebreater is not in the budget yet:smiley19:), any regulators that exhaust farther back?

If you are really serious, you might consider a double hose regulator. I frequently use a vintage double hose reg. It's not for everybody, and it does get a few looks, but there are versions that you can use that allow for all the modern accessories.

Check out Vintage double hose (http://www.vintagedoublehose.com/store/index.php) or Vintage Scuba Supply (http://www.vintagescubasupply.com/index.html) for regulators available. I'd recommend you look for a Royal Aqua Master or a DA Aqua Master as they have the ability to hook up accessories like multiple LP hoses.

RoadRacer1978
11-12-2007, 15:19
I use a bicycle innertube connected to each side of the bubble ouputs and have holes cut in the back, it works pretty good and is only a couple bucks!
What an easy simple solution. Thanks Will.

Defman
11-12-2007, 15:44
I use a bicycle innertube connected to each side of the bubble ouputs and have holes cut in the back, it works pretty good and is only a couple bucks!


Hmmm... I image something sounding kinda like a scuba version of the Whoopie Cushion!!

NitroWill
11-12-2007, 16:50
Yes, its not good if your going into any kind of overhead environments as it does dangle a bit - but it is a easy cheap solution for normal rec dives..All you do is pickup a small bicycle tire and cut it to fit around your neck (not tight, not excessive) then cut some triangle holes on the top behind your head to let the air escape..

Im suppose to be getting a camera this week - can try and get pics when I do..

CompuDude
11-12-2007, 18:51
Hmm... I seem to recall reading something about dangerous levels of CO2 buildup with something like that. Regular 2nd stages aren't designed for that kind of long exhaust column. I could be wrong, though... I'll see if I can figure out where I read that.

NitroWill
11-12-2007, 19:34
You just have to make sure there are severel ( I think I have 6) holes in the back to allow enough air to escape so you dont have any back pressure..
I have dove with this system many times for long dives and absolutely no problem!

CompuDude
11-12-2007, 19:39
Nope, I'm wrong, there is no issue with co2 buildup... must have been remembering a different thread. Or at least I can't find it.

There are other potential issues, but as long as the extensions are reasonably short and allow water in, it should be fine.

Found several thread's on SB on the issue (have to wade through a lot of posts talking about double hose rigs, however):

Frustrated with loud air bubbles - ScubaBoard (http://www.scubaboard.com/forums/regulators/182829-frustrated-loud-air-bubbles.html)
2nd stage exhaust - ScubaBoard (http://www.scubaboard.com/forums/regulators/108719-2nd-stage-exhaust.html)

NW, I'd love to see pics of your system once you get your camera. :)

NitroWill
11-12-2007, 19:55
NW, I'd love to see pics of your system once you get your camera. :)

Will do, hopefully will have it this week :smiley20:

Puffer Fish
11-13-2007, 04:24
Hmm... I seem to recall reading something about dangerous levels of CO2 buildup with something like that. Regular 2nd stages aren't designed for that kind of long exhaust column. I could be wrong, though... I'll see if I can figure out where I read that.
What it does is increase the energy of exhaling..perhaps not a lot, but there is a price to be paid for doing that. Also, just like the old days with a single hose, the breathing resistance changes with your position. Mouth up = hard, Mouth down = free flow potential.

I think that most regulator designers would strongly suggest against doing this, for safety reasons.

wgt
11-13-2007, 06:57
What it does is increase the energy of exhaling..perhaps not a lot, but there is a price to be paid for doing that. Also, just like the old days with a single hose, the breathing resistance changes with your position. Mouth up = hard, Mouth down = free flow potential.



I really can't see why you would need to use more energy to exhale. You exhale, the valve open's, the gas leaves the 2nd stage, nature takes over & pulls the gas to the surface.

Not sure what you mean by; "just like the old days with a single hose". I assume you mean the older Sea Hunt style regs that didn't have a separate 2nd stage in your mouth but had the equivalent 1st & 2nd stage in the one unit mounted on the tank valve behind your head. If these are what your talking about the dynamics are very different to Wills' inner-tubes.

Wills' inner-tubes are full of water, they're just another part of the ocean. The hose on your old style regs were full of air that fed back to the reg behind your head & so had larger pressure differentials to overcome & breathing characteristics would change depending on orientation.

I would expect minimal problems with this design, as long as the exhaust is not positioned significantly deeper than the mouthpiece. If the diver were swimming on the back while looking up, however, the pressure gradient created by the 15 - 20 cm difference in depth between the mouthpiece and the exhaust (now situated behind the head or neck) might greatly increase the effort of exhalation and thus promote altered chemistry of the blood. To test this idea, I just stuck the end of my snorkel in about 20 cm of fresh water (less dense than sea water), and exhalation was indeed appreciably more difficult than exhaling through the snorkel when it was either not submerged or just barely submerged (Will, perhaps you can test this postural hypothesis in a more natural environtment with your device and report back).

If Will indeed finds it more difficult to breathe while on his back, then we would have to think of a way around that problem. Perhaps another set of holes in the inner tube nearer the exhaust might serve to facilitate exhalation while on the back looking up through the water column but without great leakage of bubbles when the diver is exhaling in the normal swimming posture, bearing in mind that our original objective was to bypass the ears with the bubbles. This additional set of holes may also reduce chances of free-flow.

wgt
11-13-2007, 08:46
I would expect minimal problems with this design, as long as the exhaust is not positioned significantly deeper than the mouthpiece. If the diver were swimming on the back while looking up, however, the pressure gradient created by the 15 - 20 cm difference in depth between the mouthpiece and the exhaust (now situated behind the head or neck) might greatly increase the effort of exhalation and thus promote altered chemistry of the blood. To test this idea, I just stuck the end of my snorkel in about 20 cm of fresh water (less dense than sea water), and exhalation was indeed appreciably more difficult than exhaling through the snorkel when it was either not submerged or just barely submerged (Will, perhaps you can test this postural hypothesis in a more natural environtment with your device and report back).

If Will indeed finds it more difficult to breath while on his back, then we would have to think of a way around that problem. Perhaps another set of holes in the inner tube nearer the exhaust might serve to facilitate exhalation while on the back looking up through the water column but without great leakage of bubbles when the diver is exhaling in the normal swimming posture, bearing in mind that our original objective was to bypass the ears with the bubbles. This additional set of holes may also reduce chances of free-flow.

I don't think your snorkel analogy works. Think about your 2nd stage, it's air tight, air enters one end & is exhausted out the other. Once it has passed the exhaust valve it has left the 2nd stage. There's very little difference in pressure between the inside of the exhaust valve & the outside. The air on the inside of the 2nd stage is at ambient pressure, it's the same as the water that surrounds it, so there's very little effort to exhale. Exhaust T's are full of water, they're on the outside of the air tight 2nd stage, they're a part of the ocean.
If on the other hand we were to make a 20cm long exhaust T a part of the air tight 2nd stage & put the exhaust valves at the end of the T instead of the normal position we would increase the effort of breathing & in the wrong attitude may cause the system to start syphoning.

The point raised in your second paragraph is most relevant to my thinking, as I do not think that it is the displacement of air that would be the real problem. Rather, it is perhaps the displacement of the water from around the compressed inner tube, bearing in mind that a rigid structure like the snorkel ought to remain largely filled with air and not water (in the face-up diver) once the initial burst of air has been exhaled (the same as in a rigid T bent around behind the neck). I would also anticipate some residual air retained by the inner tube, which would necessarily limit subsequent compression. Under these circumstances, noticeably increased difficulty in exhaling might be restricted to swimming on the back while sinking (a bit analogous to equalizing a gigantic middle ear through an enormous Eustachian tube). In any event, it is a very interesting discussion.

I am curious to see Will's photo of his design, as it is possible that I am simply not understanding its structure, which could indeed be the basis of our differing perspectives. At the same time, in the snorkel experiment, the mouth is effectively acting as the exhaust valve of the second stage, but exhausting into the inverted snorkel need not be functionally identical to exhausting through a short water-filled port on the second stage. An experiment is required.

How is everything in Oz?

Puffer Fish
11-13-2007, 09:01
What it does is increase the energy of exhaling..perhaps not a lot, but there is a price to be paid for doing that. Also, just like the old days with a single hose, the breathing resistance changes with your position. Mouth up = hard, Mouth down = free flow potential.



I really can't see why you would need to use more energy to exhale. You exhale, the valve open's, the gas leaves the 2nd stage, nature takes over & pulls the gas to the surface.

Not sure what you mean by; "just like the old days with a single hose". I assume you mean the older Sea Hunt style regs that didn't have a separate 2nd stage in your mouth but had the equivalent 1st & 2nd stage in the one unit mounted on the tank valve behind your head. If these are what your talking about the dynamics are very different to Wills' inner-tubes.

Wills' inner-tubes are full of water, they're just another part of the ocean. The hose on your old style regs were full of air that fed back to the reg behind your head & so had larger pressure differentials to overcome & breathing characteristics would change depending on orientation.
Hummm.. ok, well there are a couple of assumptions here that are not quite correct.

If the tubes are filled with water, and you push air into them, the water would have to leave first (simple displacement). Moving water thru holes takes energy..

Once you push the air into the tube.. where it goes depends on orientation..it would go to the back, if and only if the back was higher, otherwise it would fill the tube with air, pushing out the water, and would then exit.

It is the exit point in relation to your mouth that matters.

They could have easily filled the exhaust side of those regulators with water, except that increased the amount of work.

Obviously, at some point, if you raise the holes above the regulator, the energy of the air raising would overcome the energy needed to push the air into the tube and it would get easier, and that goes to the potential for freeflowing.

This is one of those things that has been tried hundreds if not thousands of times, and the advantages (when the tube is higher than your mouth) don't outweigh the disadvantages of when it is lower.

How much variation would depend on the size, shape and vertical distance between entry and exit.

I can tell you have not used a double hose, as they, when you are in the right position, are one wonder breathing regulator...but even where you put the tank makes a difference.

BouzoukiJoe A.K.A. wrecker130 AKA Chuck Norris AKA joeforbroke (banned)
11-13-2007, 09:54
IMO, the argument about breathing effort is academic.

If you're on your back NW's bubble diverter won't divert the bubbles away as the bubbles will come up around the neck to the front of your face. So I can't think of a good reason to spend significant time on your back, so does it really matter if it's a little harder to breath that way?

RoadRacer1978
11-13-2007, 09:59
I for one can't wait to see your design Will and would be interested in trying it later on if I ever have a need, such as photography. The physics discussion we are aving here is good as well. I don't have much input, but it makes for interesting reading.

wgt
11-13-2007, 11:42
IMO, the argument about breathing effort is academic.

If you're on your back NW's bubble diverter won't divert the bubbles away as the bubbles will come up around the neck to the front of your face. So I can't think of a good reason to spend significant time on your back, so does it really matter if it's a little harder to breath that way?

Hi, B-Joe:

At least to me, the issue does not seem entirely academic. Have you ever ended a dive by brushing a population of clinging invertebrates from the bottom of the boat in a brisk current, for example? Also, taking photos under a ledge is anything but academic. How about taking pictures of a turtle swimming swiftly near the surface. The water forms a space. Depending on their interests or needs, divers may elect to make fuller use of that space.

Puffer Fish
11-13-2007, 12:12
IMO, the argument about breathing effort is academic.

If you're on your back NW's bubble diverter won't divert the bubbles away as the bubbles will come up around the neck to the front of your face. So I can't think of a good reason to spend significant time on your back, so does it really matter if it's a little harder to breath that way?

Hi, B-Joe:

At least to me, the issue does not seem entirely academic. Have you ever ended a dive by brushing a population of clinging invertebrates from the bottom of the boat in a brisk current, for example? Also, taking photos under a ledge is anything but academic. How about taking pictures of a turtle swimming swiftly near the surface. The water forms a space. Depending on their interests or needs, divers may elect to make fuller use of that space.
WGT, I would agree... I just got rid of my scubapro 650 second stage because it leaks water when you are upside down...gave it to someone that never seems to get upside down. Actually, if you are usually in a 30 degree upslope position, a double hose reg is a wonderful thing.

wgt
11-13-2007, 12:15
I'm guessing that it looks like this, but I could be way off. The pink arrows indicate where I cut the exhaust holes. In my case, I cut them too close to the ears to be effective for the intended purpose. A more midline set of cuts would likely improve noise-reducing properties. The arms on my T are also too beveled to allow a secure grip, but other T's could easily permit a good hold.

CompuDude
11-13-2007, 12:22
That's how I pictured it.

I like your diver analog. :smiley36:

RoadRacer1978
11-13-2007, 12:28
That is exactly what I had pictured in my mind as well.

wgt
11-13-2007, 12:29
That's how I pictured it.

I like your diver analog. :smiley36:

If you like my work, you should see Joe's line-up of proctological devices. It's an impressive sight, but safety remains an issue.

CompuDude
11-13-2007, 19:23
PS .. wgt, things are fine in Oz for some & not for others. We may be heading towards a fundamentalist christian fascist state in the future, politicians seem to have forgotten about the separation of the powers & our constitution, but that's a whole different discussion.

Glad it's not just us.

Kinda.

[voiceover: we now return to your regularly scheduled scuba fun chat]

Puffer Fish
11-13-2007, 20:08
Thanx for the discussion chaps, lot's of stuff to think about.

PF, I have in fact used an old double hose reg. Only one & only the one time, so not enough experience with them to even know if it was working at optimum. I found breathing was easier when I was vertical in the water column. It didn't seem to matter if I was heads up or down. At the time I thought that might have been because the mouthpiece & the reg were at the same depth & therefore there was no pressure differential. Seems I may have to rethink that idea.

I agree wgt, there are times when you may want to be in an orientation other than horizontal & facing down, so it's not just academic. I often role over on my back while finning horizontally. Sometimes to clear my mask, sometimes just to look up & see what's above me in the water column. I did that once & found I was about 15 meters below a school of hammerheads cruising past, near cacked myself.

PS .. wgt, things are fine in Oz for some & not for others. We may be heading towards a fundamentalist christian fascist state in the future, politicians seem to have forgotten about the separation of the powers & our constitution, but that's a whole different discussion.


The trick with a double hose is tank position.. the higher up it is the more vertical you have to be... and you are correct as to why that was.

As the 1st stage goes lower on your back, you would have found that your angle would go down.. you never get flat out, but you can get to about 30 degrees...

frankc420
11-13-2007, 20:12
From what I've been told, putting any kind of exhaust extension on your reg will cause it to freeflow... maybe that's a false statement, but it's what I was told. I was looking for something to divert the bubbles away from my ears at the time.


By what mechanism would a longer exhaust T cause a free flow.


Like I said, it's what I was told...

Puffer Fish
11-13-2007, 20:16
From what I've been told, putting any kind of exhaust extension on your reg will cause it to freeflow... maybe that's a false statement, but it's what I was told. I was looking for something to divert the bubbles away from my ears at the time.


All you have to do is have the extension higher than the exhaust.. as the bubbles rise, they make a low pressure area and pull air, which causes a free flow... but only if it is higher.

By what mechanism would a longer exhaust T cause a free flow.


Like I said, it's what I was told...

Chim Sui
06-18-2008, 09:50
Hi NitroWill
I bought a tube and attached it like you said.
I use the Apex TX50 and I blew through 60 bar of air descending to 27m from the surface..for some reason the tube created a vacuum effect and stole all my air!
Did you ever have that problem?
Thanks