remembering doublehose diving

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

captain

Contributor
Messages
12,121
Reaction score
14,506
Location
Laplace, LA
A lot of DA's get incorrectly ajusted because some don't understand what happens to the IP with an unbalanced diaphragm first stage as tank pressure changes. Even the original USD factory manual ajusting procedure is not the best way to do it.

Captain
 

Nemrod

ScubaBoard Supporter
ScubaBoard Supporter
Messages
13,000
Reaction score
3,808
Location
Dixie/Midwest
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?

I am not sure anyone is saying that but just to be clear the DA is a fine double hose regulator. I used my DA on the recent vintage dive trip more than my other three combined--why--
1. It was professionally rebuilt and tuned
2. My new banjo fitting for SPG fits perfect on it
3. It has quick remove hose clamps and a quick remove box clamp allowing easy cleaning
4. It is reliable and easy breathing
5. It is very pretty!!!! lol
6. It is just so 60s and I like it.

As a child of the 70s I barely got a glimpse of the 60s but dude the 60s rock and the Aqua-Master DA is the regulator of the 60s. N
 

pescador775

Contributor
Messages
2,652
Reaction score
9
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?

I hadn't heard (or maybe forgot) that the Navy DA is set at 110 @ 3000 psi. There are different instructions in my old USN divers manual. I cannot notice any difference between the Royal and the DA AquaMaster at low tank pressures and when set to factory IP settings, but the Royal definitely breaths easier at higher pressures, everything else being equal. However, there can be differences between individual regulators based on tune. Personally, I set the Royal to 120-125 psi. To go any higher invites all sorts of problems, chipmunk cheeks and freeflow. Some of the DA's had straight through hoses, no check valves which restrict flow. Not only check valves, but also the hoses, pose resistance to airflow. The Aquamaster and Royal venturi ports help overcome this to some extent. The Nemrod uses really small non return valves and long, restrictive hoses. These can only be used on the Spanish regulator with its high IP and powerful Venturi, not the Aqualung.
 

pescador775

Contributor
Messages
2,652
Reaction score
9
Personally, I think that the Mistral breaths a bit harder than the Royal. At high tank pressures, the Mistral and DA are close with a slight edge to the DA. I've never used the Royal Mistral so I can't speak to that. However, in theory it should be a terrific breather, particularly on deep dives.
 

ScoobieDooo

Guest
Messages
1,127
Reaction score
2
Location
Oneida, NY
captain:
A lot of DA's get incorrectly ajusted because some don't understand what happens to the IP with an unbalanced diaphragm first stage as tank pressure changes. Even the original USD factory manual ajusting procedure is not the best way to do it.

Captain

Yea,
Thats where I messed up. I adjusted my original DA by the Aqua Lung factory manual. That was a mistake. It didn't do my DA justice.

A vintage member friend told me that back when these regs were made in the old US Divers plant there were about eight guys assembling these regulators on tables like in the school cafeteria. They had a pile of parts in front of them. No criteria to breathe. They hand assembled them and packed them into boxes. They may have had a machine to put the regulator on and test if it did actually work, but not like what we have now with pressure guages and manometer's. If one was to pull one from the 'assembly' line and test it with another - no two performed the same and maybe 1 in 50 was actually THE best.

Most collectors / vintage divers know this today and buy and keep only the best breathers - otherwise eBay them in lieu of a really good one.

Since this diver has about 30 yrs diving experience over me - I'd have to assume they know what they are talking about...
 

pescador775

Contributor
Messages
2,652
Reaction score
9
Adjusting a two hose is usually no big deal so it may not be worth the trouble to swap it. In the later years, the AquaMaster and Royal parts were made in Japan. When the double hose were discontinued, some stores were selling off their Royals (round label) for $50. I hooked one of those new regs to a tank, turned on the air, everything worked for about a minute, then---- BLOOEY!. Air came rushing out in a violent freeflow. Post Mortem showed that the factory had installed the wrong push pin for the HP poppet. Instead of using the correct long pin they had inserted a short pin designed for the Aquamaster. The pin jumped out of the poppet's socket and became jammed against the soft material of the seat, destroying the seat.

Another interesting thing. When USD changed over to the round label they did not make new box tops to accomodate the new label, not immediately. Low serial number regs (<110000) had reformed box covers. The factory took the square label boxes and restamped them. If you look at the inside of the box front one can see the clear outline of the original square label and two slots cut in the metal.
 

Nemrod

ScubaBoard Supporter
ScubaBoard Supporter
Messages
13,000
Reaction score
3,808
Location
Dixie/Midwest
I wish I had picked up a few. I don't remember 50 dollars but I remember they did go out cheap. In the early 70s you could still buy an entire rig for a couple of hundred so 50 sounds about right.
I have two Royals, one is an earlier round label and the other a square crown label. They breath about the same. The round lablel (of mine--japan or not and I think not) has a very slight edge but I think they are both super smooth and easy breathers. I installed silicone cage valves and old stock duck bills, the thin ones, and they are just super good breathers. The quality of constuction and finish is the same on both and in fact the round label seems to have better chrome--.
My DA had been rebuilt supposedly by the past owners NAVY friend--in any case it had Royal parts incorrectly installed in the nozzle--this was a bad thing! I sent that reg out to a well known rebuilder because I did not have a parts stash to work from. He got it going again with the correct parts and tuned it and I am very HAPPY with it--it is a keeper for sure. N
 

padrediver

Guest
Messages
96
Reaction score
0
Location
Port Aransas,Texas Ft. Lauderdale,Florida
# of dives
100 - 199
My first pool dive in 1965 (age 13) was with a DA Aquamaster at the old Diver's Training Academy in my old home town of Ft. Lauderdale. My second pool dive was with a Calypso single hose. The Calypso won HANDS DOWN! My third pool dive was with a single stage Mistral double hose....harder to breathe in a POOL than the aquamaster.
My fourth pool dive was with this strange new Scubapro thing...not as good as the Calypso. Been diving single hose ever since. Still like Aqualung. Feel like 'ol Jacques
Yves is diving with us.

Anybody remember Larry Lahr and Mike Madison of "The Aquanauts" (1960)
TV series? Swinging Malibu bachelors using Sportsways single hose regs!
When I first went to SEACAMP in 1966 there wasn't a doublehose in sight!
The "Flipper" TV series sealed the doublehouse' fate. We were Florida teen
scuba divers in the sixties and the kids in the series were diving in our own backyard...with Calypso/Conshelf regs like we had.(that our parents bought for us...God bless 'em!)
 

DennisS

Contributor
Messages
4,172
Reaction score
514
Location
Sebastian, FL
# of dives
500 - 999
I have an Aqualung Aquamaster. What is a DA Aquamaster?
 

Top Bottom