Double hose regulator, how do they breathe?

[squidster]

:scubadive How do they breathe compared to single hose?
Is the New aqualung Double hose any good,
Or should a person go vintage?

 

[pescador775]

There are different brands and models. The general favorite is the Royal Aqua Master although other types are in general use. This regulator uses proven technology and compares well with the new, expensive, Mistral. Generally, these regulators are "hard" to breath compared to a slick, modern single hose like the Legend or 250HP. However, in certain positions, mainly vertical, the double hose may breath with less effort than some single hose. Moreover, a technician with experience in setting up these units can squeeze out a bit more performance at no cost. It can make quite a difference subjectively. The mouthpiece is light and comfortable and the twin hoses have a balanced feel. The mouthpiece doesn't swing around and bang stuff. The mouthpiece doesn't drag through surf and fill up with sand. Bubbles exhaust WAY out of the way. Also, they look cool and they don't freeze up, they can go a LONG time without maintenance because the box which contains both stages is sealed from the environment. There is no purge so a flooded mouthpiece is cleared by raising it up or by blowing into the mouthpiece while leaning slightly to left. The mouthpiece contains two check valves to prevent blowback of water to the mechanicals. Generally, even if the tank is completely drained, water will not enter the box in any case. Never into the internal mechanism. The double hose, properly set up with new soft parts like exhaust valve, hoses and check valves, is really nice.

 

[Luis H]

My two primary Royal Aqua Masters have a cracking effort of less than 1/2 inch WC. You can adjust some single hose (modern or vintage) to that low of a resistance, but it will probably free flow when the exhaust is higher than the diaphragm.

The mechanical advantage of the large diaphragm is great (and allows a simple mechanism).

As pescador said the environmentally sealed first and second stage is a great feature.

Now the two disadvantages:
1) In some positions you will notice the differential pressure from the diaphragm to your lungs. Most people notice it more in a double hose than in a single hose regulator.

2) The hoses and exhaust duckbill (in most) require a bit more maintenance. They should be taken apart and cleaned regularly IMO.


I just got a new (used) Mistral just for the curiosity factor. I will always prefer my Royal Aqua Masters. A Royal is the best IMHO.

If you are interested in double hose regulators, we have very active groups (NAVED, National Association of Vintage Equipment Divers) and web sites that you should visit and join.

VintageDoubleHose.com
VintageScubaSupply.com
and the Sea Hunt section on this board (under general equipment)

 

[captain]

When I began diving the double hose regulator was the only type available. When the single hose was introduced and the double hose was discontinued I switched to the single hose. About 4 years ago I began using my double hose again. Is there a difference, well yes and no. The double hose will suppy enough air for just about any situation. Cousteau used them below 300 feet. As pescadore said breathing effort will vary depending on body position and tank placement. The tank needs to be worn lower than with a single hose to get the regulator closer to the center of the lungs. Just like and odor becomes less noticeable the longer we are exposed to it the difference between the single hose and double hose becomes less noticable the more it is used. The main disadvantage to the vintage double hose is in connecting octos, BC inflators and SPG's to them. It can be done just not as simply as with a single hose. A lot of double hose divers tend to not use BC's. Go to the Sea Hunt section of General Scuba Equiptment Discussions, there is a lot of double hose info there.

 

[cudachaser]

My Royal Aquamaster served me well for years....Even brought it to the "new world" when they came out with an adapter to allow use of an SPG. I finally replaced it with a Voit MR-II single hose which is essentially the same as Mares lines available now.

The "Royal" breathed better than any other reg I have used.

Joe

 

[Nemrod]

Phoenix Royal Aqua Master, it knows no equal, past or present.

Parts bin USD DA Aqua Master with Royal nozzle assembly with Titan parts, new silicone diaphram and Air Buddy octapus on hookah port adapter, faux Voit grey hoses and new Navy mouthpiece. It breaths awesome.

Voit and USD double hose regulators have the best parts support on the aftermarket. All sorts of fantastic stuff is coming out for them. Take a look at www.vintagedoublehose.com and www.vintagescubasupply.com. They also service them. New parts are being made, parts from current Aqua Lung regulators can be adapted to the Royal Aqua Master. Not only were the Voit and USD models most common but they breath fine and are easy to rebuild.

Properly tuned and rebuilt with quality parts they can perform on par with modern regulators or even better. They are different however, you must understand that up front. Positioning, clearing techniques and just the way they breath and respond in general may take some getting used to--for the better.

Don't bother with that "new" Mistral, get the real deal. BTW, the two regulators pictured above are just peachy keen with 3,500 psi air.

N
NAVED Master Diver 111
New equipment is over rated, live free and dive vintage

 

[Nemrod]

I have one of those plastic fantasitc Aqua Lung Legends with the knobs and vanes and free octapus I finally got and it breaths OK, no better overall than the Phoenix Royal Aqua Master. Once something like WOB get's to a certain point does it matter if something is gooder than good or better than best, it just does not mater anymore at these levels of performance. The big difference, the robust and reliable Royal Aqua Master will still be going another 30 years from now and somehow the plastic fantastic Legend I fear will not make a decade or even a few years. To flimsy, fragile, finiky.

N

 

[Chico Bozo]

Hey Nemrod,

Great name by the way....I still remember "Nemrod by Seamless" .....sold at the local (?)...

Let me pluck some of your knowledge and tell me about the "Royal Master". I recently acquired one of premium quality and wish to know more about this model. Especially the differences between it and the 'Royal Aqua-Master".

Thanks...CB

 

[Nemrod]

Chico, hello, welcome to the double hose club. I do believe that the Royal Master is no different than a Royal Aqua Master. Why don't you join the vintage forums at www.vintagedoublehose.com and www.vintagescubasupply.com.

Also, you will find the needed parts to make it like new through the forums. Not only do the two forums have stores but many people buy, sell and trade among ourselves, especially knowledge.

Another useful link:

http://www.calclassic.org/Regulator/aqualung.html


I can say that your regulator, if truly mint or even close, is fairly valuable. Now, don't get visions of great fortune, but it is a desirable and relatively more rare model. I am happy for you that you have found it and in good shape. I definitly recommend, for the first rebuild after retirement(lol) that you send it to one of the above sites, the vdh site has wonderful new silicone main diaphrams for example, after learning more then you can do subsequent rebuilds on your own. It may need nothing more than a good cleaning and tuning, better to be sure and safe.

Ah, Nemrod by seamless, maker of fine diving gear, alas, they are history. Check this out:

Nemrod triple manifold compared to an equally vintage USD twin manifold. Pretty neat huh. Oh, the name was given me by the nuns, I am NEMROD, Hunter of the Depths (ha). N

edit for correcting terminology

 

[Luis H]

You probably already know that the Royal Master was the predecessor to the Royal Aqua Master and was only available in 1964 and 65. The last link that Nemrod provided will confirm that.

I haven’t personally worked on a Royal Master, but the pictures I have seen of the parts showed that the first stage springs were different from the RAM. I can’t recall the details, but I believe (at least some of) the Royal Master had two concentric springs between the HP seat and the spring block.

Also my understanding is that those parts could be replaced with the newer Royal Aqua Master first stage parts. Therefore, if you regulator was ever serviced, it is possible that its parts have been updated.

Sorry that I don’t have better information, but the little I know about the RM is from the other two web sites Nemrod mentioned. If you join and post your question on those sites you will probably get a lot more precise information.