remembering doublehose diving

[JaxvilleDiver]

Yea,
You and most of us! I wish I could get a late model Royal for less than $250 in nice condition!

That's about my limit too...

 

[Nemrod]

A good Royal, unless your very lucky and it happens, is going to cost more in the range of 300 to 400 dollars. Even rough ones run up over 200 dollars.

Ebay hint---many people selling this stuff have no idea what it is--look under catagories other than vintage. The cherry, mint, beautiful, fully original, freshwater only, works like a dream, never opened round lable Royal that I have was listed as a scuba valve and very few people noticed it. The other, almost as nice crown label Royal I have ran up to 375, rebuilt now it too breaths like a dream!
By the way, I still have the "old fellow" DA, a rebuilt unit with some minor corrosion damage that has been cleaned up for sale at 250 dollars neg. with new hoses, valves etc. A functional workhorse but not museum mint.
A good DA is a great double hose for cruising around a reef and playing frogman. Truth is and I now understand, a DA, even a really good one on it's best day, will never breath like a Royal. If a fellow were trying to dive with atheletic guys using modern single hoses at depth and your trying to keep up I am afraid that, IMO, you will need to ante up the bucks for a Royal. I could be wrong and I love my DA, cruising along the Destin Jetty recently with it was a delight. N

 

[Bob3]

... Looking at the back of the main casting (the exterior) it can be seen that there is a low pressure chamber which forms a distinct bulge and terminates in a relief valve port on top....

I've seen guys that have run a LP hose out of that relief valve port, I wonder how good of an idea that is... the threads don't match up all that well w/the standard 3/8" & where's the OP going to go if the 1st stage starts to run the IP up...

 

[pescador775]

I've seen guys that have run a LP hose out of that relief valve port, I wonder how good of an idea that is... the threads don't match up all that well w/the standard 3/8" & where's the OP going to go if the 1st stage starts to run the IP up...

Not a good idea at all.

 

[pescador775]

Nemrod, there is a lot of stuff circulating around as to why the Royal breaths easier than the AquaMaster. One story goes that the HP orifice is larger. Not so. Actually, the approach for modifying the AquaMaster was related to the fact that the first stage of that regulator uses an unbalanced valve. The effect of this is to cause lower IP at higher tank pressures making the Aquamaster harder to inhale on a full tank. This effect is counterintuitive and is the opposite of that experienced with a simple unbalanced piston stage, and results from closing forces (air pressure) acting on the end of the poppet valve stem which controls the flow in the Aquamaster first stage. The Royal, on the other hand, encorporates a brass balance chamber which fits over the end of the poppet stem and is sealed with an O ring. The poppet stem is drilled to allow low pressure from the second stage intermediate chamber to fill the balance chamber. Consequently, the only pressure related closing force that the end of the poppet valve stem sees is the 110 psi of the IP side of the regulator. The closing force on the Aquamaster (unbalanced) poppet stem can vary from 100-3000 psi. As small as the stem is , this pressure variation can nonetheless play havoc with the regulators IP and , hence, the breathing response at the second stage. The Royal solves this problem of variability and allows the second stage to respond the same at all normal tank pressures.

 

[Nemrod]

Hi pescador, yes, I understand and I have had them apart and looked at them and I also have the manuals. I also understand the variation of IP with tank pressure that the unbalanced DA experiances and why it happens. All that is fine but both my tuned Royals breath easier than my equally tuned DA regardless of tank pressures. This has been my experience with both my Royals vs both my DAs. The Mistral also breath easier than either DA once the tank pressure gets below approx 1500ish psi.
Next time I have them apart I will pay attention to orifice diameters but just on memory I would swear the Royal is larger but I did not have them apart at the same time to make a side by side comparison.
I am not r unning the DA down, it is a fine work horse, it just does not have the all out performance of the Royal based on my units---could be wrong. N

 

[captain]

I don't have a Royal and I am not sure what the Royal IP is set at but if you go by US Navy specs per the 1970 diving manual the DA IP is set at 110 psi @ 3000 psi tank pressure. From 3000 psi on down the IP is increasing until it is about 135 - 140 psi @ 500 psi. If the Royal IP is also set at 110 psi than the DA should out perform the Royal at any pressure below 3000 psi as the DA's IP is increasing and the Royal's is not. I have two DA's and a Mistral and both DA's breathe better than the Mistral at any tank pressure.

Captain

 

[Nemrod]

"If the Royal IP is also set at 110 psi than the DA should out perform the Royal at any pressure below 3000 psi "

Helo Captain! Did you get your boat in the water yet?

Back to regs----But it seems the DA doesn't out perform the Royal and I guess that is the mystery. It seems to me that the DA breathing reqiures increasing effort (relatively speaking) as the tank empties whereas the Mistral gets easier and easier and the Royal is just easy all the time.
Hey, I saw a couple of dozen double hosers hanging in your truck--you got more than three I think--lol. N

 

[captain]

I guess I will have to try a Royal to see for myself. No, the boat isn't quite ready yet. All those regulators you saw was an optical delusion caused by too many sand dogs.

Captain

 

[ScoobieDooo]

So I'm confused! If the Royal is engineered to perform better and be an improvement over the DA's then how can anyone claim that the DA's actually breathe better than a Royal? I can't see how this would be so?