Dove my first vintage double hose today

[jacked_72]

Got up early and headed off the the quarry to check out my DA Aquamaster that I finished rebuilding. All and all it was a bit disappointing, though it seemed to work. I just don't know if it worked as well as it was supposed to.

I found the original us divers mouthpiece very uncomfortable. I wouldn't call the problem jaw fatigue, but more of jaw pain. I wound up just wrapping my lips around the retainer and not using the bite tabs. It worked out a little better.

At the surface, the reg free flowed like crazy. At 20 feet it was very difficult to breath. I know now what people mean when they say it felt like getting air through a straw. Not really that bad, but it was difficult to breath. Exhaust breaths were easy. It might be my imagination, but it seemed to breath easier if I was vertical and harder to breath in a horizonal position. I kept thinking how was I going to know when I was low on air as I thought it was tough to breathe with 2000 psi.

On the positive side, I had no issues, no leaks and no surprises. I'm sure a balance reg would do better and it might have performed better if I had a silicone diaphragm. I may tweak the second stage a little bit, but with that much free flow, I don't know how much adjustment I've got.

I'm glad I got it working and it sure looks neat.

 

[simonbeans]

Your experience is definitely not typical. Yes, there will be a difference of breathing characteristics in regards to position in the water, laws of physics, you know. However, what happened to you indicates something is not right with the reg. Your post indicates you rebuilt it. Have you had any experience with rebuilding DHs or any other regs? Before you make a definite decision on its operation, I would suggest 2 things. 1) Have someone who works on these all the time assist you and 2) go to Vintagedoublehose.com and read all the information on experiences divers who use these all the time have.
I have too many diveable double hose regulators and have never had the kind of experience you had. Get that looked at and then dive it. I am sure your post next time will be more positive.

 

[herman]

It's really hard to diagnose problems remotely but I have a good guess what the problems are. Having serviced a lot of DH regs and having done a lot of "try DH diving" presentations I am betting you have 2 problems that combined make diving a DH rather unpleasant experience. They are reg tuning and diving techniques. There is more to rebuilding any reg than simply installing parts, they need to be adjusted or tuned to work together and some "good" parts aren't really good. Reg tuning is more than I care to get into here needless to say, it's important. That is the reason I recommend anyone wanting to learn DH diving start with a DH serviced by someone who does it often so they have a known starting point. One thing that does stick out is your uncomforted with the mouthpiece. Assuming it's a curved one, sounds like you do not have it properly adjusted. If they are, it should easily rest in your mouth. I much prefer a properly set up DH mouthpiece than a single hose any day.

Then there is diving technique, this is just as important and based on our comments, I suspect you are missing some of the major points of DH diving technique. I highly encourage divers who want to try DH diving to find an experienced, active DH diver as a mentor (I learned the hard way). Someone who "dove them in the day" does not cut it, you need someone who currently dives them and enjoys diving them. When I do "try DH diving" days I spend a lot of time goining over the differences between single and double hose diving so my students know what to expect. Freeflows are NORMAL at the surface if you are vertical or on your back, common positions for single hose divers but an experienced DH diver either does not get into those positions or holds the mouthpiece under the water, if is doesn't free flow in those positions is when you worry. The regs SHOULD breath differently at different body positions, this is expected, understood and anticipated by an experienced DH diver, it's another one of the differences that single hose divers do not expect. In a properly tuned and worn DH it's not as noticeable as in a poorly tuned or improperly worn reg. Next problem I suspect you have is the reg position, it MUST be worn low, between the shoulder blades and held CLOSE to your back. To put it bluntly, you can't dive a DH with a jacket BC and expect anything better than poor performance, same goes for BP/wing with a STA or worn high as is done with a single hose reg. You need the proper tank holder for a DH reg, even the double thick "blown" plastic BPs are not suitable for DH diving.

I have a lot of regs to choose from but my go to reg is a fully tricked out DH reg (Phoenix,full silicone parts, Voit mouthpiece and duckbill eliminator). I encourage you to find a mentor and get some assistance before writing off the DH reg.

 

[spectrum]

jacked_72

Your experience sounds like common novice issues.

Assuming the mouthpiece is in good shape and is probably is since you mentioned the bite tabs you will get accustomed to it. It is different than the more common long bite single hose mouthpieces. Once you are accustomed to the different gear you will relax and this will become a nn issue. Do check the orientation of the mouthpiece. It wants to be positioned to plan neutrally in your mouth. You don't want the hoses wound like torsion springs. Loosen hose clamps and rotate as needed.


What you call free flow is probably normal. If the regulator can is underwater it is several inches of water column below surface pressure and it will deliver. On the surface you need to keep the mouthpiece under your chin or even lower so it is pretty near neutral to the diagram's depth. Some have played around with valves and plugs buit it's mainly an new awareness skill.

Air delivery is a wildcard. Being unbalanced you will start your dive with the greatest cracking effort. The BC wants to position the regulator as close to your your lungs as possible and you need to be in good trim so the depths are close. These regulators generally are not air sippers. Make your inhalation a little brisk so the venturi can assist you. You can then enjoy an exquisitely slow exhalation and do just as well on air usage. Newer silicone cage valves and the diaphragm as well as general settings and condition can all be contributors to improvement too.

As for monitoring your air, consider a banjo fitting if a Phoenix upgrade is not in your future. If nothing else get onto J valves or bring a pony.

Pete

 

[jacked_72]

Thanks for the info. I did have a pony, so I've got that covered. I had the reg on a jacket BC and it was very high, much higher than Herman describes. I'll see if I can't also rotate the mouthpiece for more comfort too.

 

[DaleC]

The first time I dove a doublehose I was very conscious of the work of breathing (WOB) it required - I felt there was something wrong. After a few times I found my respiratory muscles got used to it and now I don't notice. I also found my mouthpiece on one reg awkward but this was fixed when I rotated it on the hoses so that the mouthpiece rested naturally in my mouth. Otherwise it was prying at my mouth trying to straighten out to its natural position.
So, if mechanical issues can be eliminated as a source I would say give it some time. Diving a DH is somewhat like driving an old manual transmission sports car compared to a modern automatic. Yes, one is easier but the other really asks you to be aware of the road and allows you to experience the ride more directly.

 

[simonbeans]

Let's start with the simple, quick fixes. Herman is right on about mentor. But to do somethings on your own, we can begin here.
To allign your mouthpiece. Lay the reg on a flat surface. Losen the clamps on the mouthpiece or can end of both hoses. Turn both hoses until the mouthpiece lines up in a straight line with the center of the cans. See this picture:

Tighten the clamps. With the reg in the exact position for optimum breathing, i.e., between the shoulder blades, the mouthpiece will be aligned for most comfort.

Next, PM Herman or contact Bryan at VDH, to address the regulator issues.

 

[cloudflint]

Moving to a twin hose i had very similar experiences. Ive found there is a certain art to diving a twin hose, its a bit like riding a bike. Yes it falls over if you try to leave it standing since it only has two wheels/free flows if you lie on your back with the mouthpiece out due to the demand valve position. Yes when you initially try it you will fall over alot/find it breathes terrible. Even once you get the balance right, your muscles will hurt/the breathing will feel weird. As Herman said, you wouldn't want to rely on someone who used to ride a bike/ dive twin hoses years and years ago, you want to find people who use them currently!

However given time and a little practice all these problems dissapear. You'll find the sweet spot for reg positioning (between the shoulder blades as close to your back as you can get it), youll find out how to deal with these regs characteristics (When on the surface I find putting my arm through the hose so its running under my right arm puts the mouthpiece below me allowing me to swim on my back without free-flow) and you will get used to how the regs breathes (Having now spent more time on twin hose regs than single hose ones, I find it takes me a while to get used to the really weird way single hose valves breathe!).

 

[herman]

When setting up the mouthpiece as Allan shows, move the hoses AT THE MOUTHPIECE, otherwise you stand a good chance of twisting the duckbill (if you have the DB eliminator either end is fine). It may be best if you take the hoses completely off, allow them to find their own straight position then slide them straight on, otherwise you may still have some twist in one or both of the hoses. From that postion you may find you want to tweek it a little but it will put you close in the ball park. When diving the mouthpiece should rest square with your mouth and easily hang there. Re reading your first post it sounds like you have the guard outside of your mouth.....it goes inside between your gums and lips with the bite tabs gently between your teeth. I find it much more comfortable that a single hose. That being said, I do not like the straight mouthpieces, they are too big for my mouth, the curved ones are much better and if you don't care about the "correct" mouthpiece on the reg, the reproduction silicone Voit hour glass style are hands down my favorite.

The breathing cadence for a double hose is a loooong slow inhale followed by a long slow exhale, works fine for a single hose as well. Quick breathing is fine for a single hose reg but is not acceptable for a DH reg. As for a balanced reg breathing better, it's not as much as you would expect - assuming a properly set up reg- and because the DA is an unbalanced diaphgram reg, it actually gets easier to breath as tank pressure drops (unlike an unbalanced piston reg) until you get below IP when it starts to get hard fast.

 

[captain]

I think there are some tuning issues here. There is the book way and the right way.