Dove my first vintage double hose today

[Ed Palma]

I remember my 1st DH dive just over a year ago. I was lucky enough to have gotten a reg that was tuned by Bryan and had new parts in. I was also lucky enough to have done prior reading on proper positioning and technique and also got a load of advice from many members of the forum here and especially over at VDH, so I knew what to expect from my DAAM. Breathing from it for the 1st time was just a beautiful thing.

The other posters above have given very sound advice - I would know because they're the same ones who helped me out in my nascent DH days One thing I will add is about the mouthpiece. When I let my sister use one of my DHs for the 1st time, she too complained of jaw fatigue. Turns out she thought it was necessary to bite down hard on the tabs. I told her to relax and let the buoyancy of the hoses hold the mouthpiece in place.

Another thing I'll add. 1 year ago, I was told that I was getting into DHs at an exciting time, considering that new products were available to restore and improve the performance of the regs. Well, this time around, I'll echo the same sentiment because there are even MORE things currently available to improve them.

 

[Paladin]

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.

Double hose regs don't play well with jacket BCs. If the top of the regulator can is higher than your shoulders, it will not breathe well at all. It simply must be below the shoulder line and as close to your back as possible. I use an old backpack instead of a harness for ease of switching tanks. The backpack is not the ideal choice but I'm willing to make the trade-off in order to switch tanks but the harness is better for performance.

If you're going to use a BC with the DH, then a horse collar is a good choice. A BP/W can work, if you get the right one. I prefer the horse collar.

 

[elan]

Nothing really to add, the gentlemen really explained everything well.

You need to keep the points mentioned here to really enjoy diving it, after you learn how to dive it properly you will see that it breathes easier that any single hose, it never freezes and you can dive with your mouth open without the mouthpiece falling out (the buoyancy of the hoses plays the trick) No jaw fatigue issues.

 

[Sam Miller III]

All of this verifies the need for a national double hose regulator training program--before some one buys the farm

In the interium study from an early issue of the many training manuals of that era, especially the "The science of skin and Scuba diving"or the later edition "The New science of skin and Scuba diving;" find a local qualified mentor, and practice and practice in the pool.

Then and only then resume diving in open water

sdm

 

[macado]

People way smarter than me and with many many more years more double hose experience have commented here but I want to agree with what everyone else said. I'm currently working on my 4th and 5th double hose regulator rebuild projects so I'm also still learning the ins and outs of properly tuning them but it sounds like your reg should be breathing better than you described.

Positioning is absolutely crucial to getting optimal breathing performance. It's very hard to get that with a jacket style BCD, modern BCDs place the cans far too high and off your back.

It does sound like the regulator may also have some tuning issues. What is your IP set at and what tank pressure did you use? I believe the

silicone diaphragm will certainly help but it's not the whole piece of the puzzle. Horseshoe lever properly aligned? ​

 

[jacked_72]

Right now I'm thinking that the positioning of the regulator on my back is the biggest issue to address. I had it very high. I'm hoping that moving it down will improve things. It was difficult to breath, but I wouldn't consider it life threatening. Also, I had my octo from my pony right there so I'm wasn't worried about buying the farm.

The IP was set to 115 psi +/-. I didn't measure the cracking pressure with my magnehelic gauge, but based on my single hose regs that I have measured, I'd guess its in the 1-1.25" range. Of course, I suppose its all relative to the mouth piece and regulator plane. Tank pressure at the beginning was 2000 psi and at the end was about 900 psi.

Thank you all for your comments and suggestions. I think it a matter of fine tuning some things. If anyone knows a VDH mentor in Dallas, please let me know.

 

[spectrum]

How was your trim? Feet (lungs) down and regulator high on the back makes for high work of breathing.

 

[captain]

All of my two hose regulators have a cracking effort of less than 1". I shoot for .5".
Arriving at that requires attention to IP setting. I set it at 135 psi on a tank pressure of 300 psi, at 2500 psi IP will be about 20 to 25 psi lower. Horseshoe height as high as possible without a free flow when the diaphragm is installed and the top can clamped in place. This is important, tabs on the diaphragm have to be carefully centered on the horseshoe ends. Do not twist the ends of the horseshoe supports, the horseshoe will not fall off and twisting the ends can cause a bind in horseshoe movement.
I been doing DAs for 50 years, they should breath just as good as a single hose in most situations if set up right and worn properly positioned. If you can bend your head back and it hits the regulator it is too high. A crotch strap helps to keep it low on the back.

 

[salimbag]

I dive a 1957 Aquamaster all the time, and switch to a modern single hose (Scubapro) for about half my dives. I notice no issues at all - they breathe comparably, and I have to really work to find that exact weird position where I get a free flow - it's NEVER happens spontaneously, unless I'm turning somersaults, and then of course briefly. I got the reg in 1957 and have only replaced the duck valve and the hoses once. (I only use it for fresh water diving). I am always surprised to hear of problem with these regs.

 

[John C. Ratliff]

I agree with all the detail stated here, except the need to send it in for rework. If it is not leaking air, probably the major problem is the positioning and the hose orientation. Concerning the interstage setting, in the US Navy Underwater Swimmers School there was a very interesting way of setting this. Take a tank at 300-500 psig, and put the regulator on that. Adjust the main spring until it just barely leaks, then back it off 1/4 turn. The will give about 1/2 to 3/4 inch of suction effort for the DA Aquamaster at low tank pressure, and somewhat higher at full tank pressure.

Dr. Miller above said something that is very, very important. A person should have some training before trying this out in open water. Getting with an experienced double hose regulator diver and hopefully getting some instruction will keep the two errors mentioned in the op-ed from happening. Having the DA Aquamaste mounted "very high" gives in and of itself about a 12 inch suction effort! This is the "sucking through a straw" that was described. It is not the regulator's fault. Look at the photo of Herman with his twin 50s, and the position of the regulator on his back. This is almost ideal (I like it even lower). Before diving this regulator again, I would urge you to "qualify" it at least in a pool setting, and hopefully with someone who knows about double hose diving by actually using them.

SeaRat