Double Hose Regulators

[Norm]

I own a double hose but I do not dive it. I did once, years ago in a pool, and I couldn't believe the added breathing resistance. I was impressed by your poll though.....I am familiar with the Aqua Lungs, the Voits, the Healthways and the Nemrods, but I had forgotten all about the Northills! I did see an ancient Buddy L once. I am not personally familiar with the Diveairs, Medis, or Siebe Gormans. Thanks for bringing these to my attention.
Norm

 

[dmdalton]

I've got my original Voit Polaris 5o that I bought new in 1962 and dive from '62 until 70. Just picked up new hoses for it and new duckbill vlave. I'll dive it for grins this coming year.

Dave D

 

[John C. Ratliff]

I have dived double hose regulators for a long, long time. My first one was a Healthways SCUBA regulator, with blue hoses and a Hope-Page mouthpiece that I bought in the early 1960's. I have used most of the double hose available in the US after about 1965, and can give you some information on specifics privately if you wish. I will, at a later time, detail some of this information too, and I have commented also on the regulator freeze-up thread.

Double hose generally have pretty good breathing characteristics. But, positioning is everything with the double hose. The regulator should be between your shoulder blades for optimum performance. If you don't have a US Divers or Voit double hose, consider changing the hose/mouthpiece system to the USD system. It makes a big difference in the breathing of the regulator. This is why using double tanks is the norm when using double hose regulators. The water column above your lungs is what is causing this breathing resistance.

Before diving any double hose regulator, be sure the hoses are clean. The easiest way is to wash them out with soap and water using a bottle brush. If you don't know the history of the hoses, DON'T DIVE THEM. They may have fungus growing inside. You can decontaminate them with an antifungal agent, but it would be better to replace them. Washing them with a bottle brush will tell the story.

Breathing resistence is also increased because the non-return valves in the mouthpiece stick or deteriorate and become hard. While the regulators can be dived without these non-return valves, it is not advisable as the entire intake hose can become flooded when the mouthpiece is out of your mouth.

Most people trained by the US Navy (I was one) increased the intermediate pressure of the Aquamaster to just where it would free flow a bit an about 500 psi tank pressure, then turned the adjustment back 1/4 turn. (For the Royal Aquamaster, it didn't matter to test it at 500 psi as it was a balanced diaphram first stage, but the Aquamaster had an unbalanced diaphram first stage, which increased the intermediate stage pressure as the tank pressure dropped.)

The exhalation was much better than most single hose regulators, even today, due to the duckbill valve design and it's location on the diver's back.

If you have a DA Aqualung regulator (two stage, but without the hookah attachment on the back), DON'T DIVE IT! This regulator was the first generation, and had no venturi. The air jetted into the back of the case, and it was a very, very hard breathing regulator, to the tune of 5 or 6 inches of water pressure. This is for the mantle onle.

SeaRat

 

[rag]

John C. Ratliff once bubbled...
Before diving any double hose regulator, be sure the hoses are clean. The easiest way is to wash them out with soap and water using a bottle brush. If you don't know the history of the hoses, DON'T DIVE THEM. They may have fungus growing inside. You can decontaminate them with an antifungal agent, but it would be better to replace them. Washing them with a bottle brush will tell the story.

Fungus!? I better check my hoses then. If I find all sorts of nasty things growing in the hoses, what stuff should I use to disinfect them? Obviously something that doesn't deteriorate the hoses, but what?

I've a refurbished DA-Aquamaster that I tested last summer. After diving, I rinsed the regulator, and also poured water in the exhaust hose thru the mouthpice and watched it come out from the exhaust valve in the regulator case. But I never took the hoses off.

How often should one clean the breathing hoses? Once a year? After every dive? Anyway, I'd appreciate any hints on the proper care of double hose regs.
---

 

[John C. Ratliff]

Before becoming too alarmed, look at the mouthpiece non-return valves. If they are intact (especially if they are the newer silicone, or white, rubber), chances of water with contaminants getting into the inhalation hose are small. Therefore, chances of contaminating your breathing is small.

But if these non-return valves have deteriorated, and water has gotten up the intake hose, you may have a problem. Usually, even this is not much of a problem, as the air pressure itself will keep most water out of the hose. Now feel the inside few inches with you finger. If it's slimy, then it needs to be washed.

The exhalation hose is a different question, as saliva constantly goes down this hose. Therefore, it needs to be washed often, really after each dive. I haven't always done that, but that would be my recommendation.

The US Navy, in the 1960's, decided that after each dive the hoses should be decontaminated. We had to take the hoses off, and let them sit for 10 minutes in a disinfectant solution. I really don't know if this was necessary, or the Navy's idea of a different type of "gear harrassment" with the aftertaset it left. I also don't know if that was specific to the US Navy School for Underwater Swimmers in Key West, or was Navy-wide. However, the US Navy Diving Manual of March 1970 calls for, under 3.4.9 Maintenance, "(3) Establish a definite maintenance schedule to insure that all scuba are kept in top operating condition. (a) Provide for the disassembly and overhaul of regulators, tubes, hoses, and masks every 6 months as described in the applicable NAVSHIPS Instruction books."

Under the "Mouthpiece Assembly" in section 3.3 EQUIPMENT, the US Navy Diving Manual March 1970 states:

(17) THe mouthpiece assembly includes all breathing circuit components between the mouth and the breathing tubes. It may include a mouthpiece connecter, cutoff valves, breathing check valves, and a surface breather valve. Most commonly it consists of the mouthpiece and a simple T-connecter for the breathing tubes. The cleaning procedure for this assembly is as follows:

(a) Disassemble breathing hoses and mouthpiece.
(b) Clean all exposed parts by scrubbing with detergent (DETERGENT, SURGICAL, 5 onces) and suitable brushes (for hoses, BRUSH, FLASK, 4 1/2 inches; for mouthpiece, BRUSH, TEST TUBE, 1 1/8 inches). THe interior surfaces of air hoses must be thoroughly scrubbed.
(c) After rinsing with fresh water, immerse all rubber parts in a 100-ppm chlorine solution for at least 2 minutes prior to reassembling. One-quarter ounce of CALCIUM HYPOCHLORITE, TECHNICAL (70 percent available chlorine) in 12 gallons of water approximates a 100-ppm chlorine solution. Mouthpiece assemblies containing metal parts should be sterilized in a noncorrosive disinfectant (DISINFECTANT, GERMACIDAL AND FUNGICIDAL, 1 quart; or DISINFECTANT, GERMICIDAL AND FUNGICIDAL, 1 gallon). Disinfectant must be completely revoved from the apparatus before it is used.

I personally check for slime buildup, and wash accordingly, but at least once every several months. I still simply use diswashing soap to clean them, rinse them out in the clear water, then take them outside and whirl them hard to remove the water from inside them (do this someplace where you can spray water around, rather uncontrollably). This should suffice (most diswashing soaps now are antibacterial and antifungal, but if it's been some time, the US Navy way would be the best.

Good luck, and good diving the ol' double hoses.

SeaRat

 

[pescador775]

The accepted method of disinfecting a double hose is mild solution of Clorox. However, I've never had a problem with fungus, etc in my regs. The check valves prevent water from entering the intake. When washing the reg jet some water into the mouthpiece and blow through. This cleans the exhaust hose. Silicone check valves last forever. If you have the old neoprene valves use them but remember to replace after a year or two. You can make your own silicone valves. Cut disks from a thin sheet of silcone and attach to the valve body with a SS sheet metal screw.

When I strapped on my first SCUBA in 1955 the regulator was a 'Seahorse' double hose, converted aviator's regulator. Following that I used a Divair for several years. Finally, after college, I could afford the best, a Royal Aquamaster. I dove that until 1976 when I connected a Conshelf first stage with a Scubapro second. I dove that setup for 10 years until purchasing a MK10/G250. All of the above regulators, except the Seahorse, are in use, albeit only occasionally for the double hosers.

The double hose sometimes gives a newbie the mental sensation of air starvation because of pressure differential or because it does not 'jet' air into the diver's mouth. However, the well tuned double hose, although harder to inhale, has a smoothness, dry texture, consistency of air delivery, and easy exhalation, which quickly builds confidence. One might also note that the double hose is quieter since bubbles do not pass by the ears.

 

[John C. Ratliff]

A lot of people have made the mistake of taking off the hoses of a two-hose regulator, and not putting the back on correctly. If there's a twist in the hoses, the mouthpiece won't be comfortable. The mouthpiece should point directly back at the regulator when the regulator is face-down on a flat surface. Another way of testing is to hold the regulator vertical, and balance the mouthpiece on your finger. It should point horizontal with the regulator about three to four inches below the mouthpiece.

One other thing that's particular to the US Divers/Voit/AMT Trieste regulators is that the flutter valve is particularly suseptable to deterioration. Left in the regulator, they may adhere to the side of the regulator and be very difficult to remove at all, much less intact. Be prepared to replace duckbill flutter valve frequently, and they are still available at Vintage Scuba on-line (as I found out from this site). To make them last longer, take them out after use, put silicone grease on them, and store them in a plastic zip-loc bag. That way, heat, chemicals and ozone won't get to the rubber. Put it back into the regulator case by using the eraser side of a pencil to push it into position. Visualize it through the holes, and make sure the duck bill is oriented parallel to the diaphram, and is about in the middle of the diaphram (or it will leak air when in certain positions). Then fold it over the case opening, and put on the breathing hoses.

Good luck,

SeaRat

 

[ScoobieDooo]

Does anyone know where parts breakdowns and/or service manuals can be had for Royal Aqua Masters?

Anyone have one in PDF format or otherwise?

Thanks,

 

[ew1usnr]

You guys left Dacor off of your chart. My brother has a circa 1965 Dacor R-4 that is a beautiful regulator, breathes as nice as any of my Voits or USDs, and is built like a tank. The Dacor design was unique in that it had an inner and outer diaphram and could continue to function if either diaphragm failed. It also uses a flap valve for the exhaust instead of a duckbill valve. The flap valve is much less prone to disintegrate over time like the duckbill does.

 

[DA Aquamaster]

I own a fully operational DA Aquamaster as well as a fully functional Mistral.

I like the performance of the single stage Mistral better than the DA but I suspect the DA could benfit from some adjustment.

New hoses and mouthpieces for US Divers double hose regs are being produced in England and sold in the US through the going down under dive center. Duckbills and mushroom valves are still available.