The DA Aqua-Lung Regulator

[SeaRat]

This thread is devoted to the first regulator imported and produced in the USA by US Divers Company, the DA Aqua-Lung regulator. I have owned several, but kept only one, a Broxton-addressed DA Aqua-Lung. It was used only once in the 1970s, and almost caused an accident due to it not being serviced correctly. Recently, that was corrected. Here's a report:

I took all three of my Healthways Scuba regs into the pool today, along with the DA Aqualung that I got back from Chuck. I'm going to start another thread with a more detailed report, but suffice it to say that the DA Aqualung breathed better than the first two generations of the Healthways Scuba, and provided all the air I needed.

Since this is a Healthways Scuba thread, I'll discuss my findings about these three regs first. I took the DA Aqualung into the water first, to establish a baseline, then took the Healthways Scuba regs into the pool. The original Healthways Scuba (see the blue-hose beauty above) worked pretty well, but did not have a good exhalation as it did not have a duckbill valve imbedded into the exhaust system. So water came into the hose (see my experiments earlier). I was using it with a Hope-Page mouthpiece and Dan's super-flex hoses, and they worked extremely well on this regulator.

The second test was to take the Healthways Scuba Deluxe regulator into the pool. It has the same mechanism as the original Healthways Scuba, but has a mushroom valve exhaust. That exhaust was partially blocked by the diaphragm (again), as I was using the original Healthways mouthpiece, but without a non-return in the intake. As a matter of fact, the only reason it was as good as the original Healthways Scuba is that I have removed the mushroom valve cage from the intake of this mouthpiece. Also, I used Nemrod Snark III hoses with this mouthpiece, as the original hoses are too short (in my opinion) to be practical. With these modifications, the inhalation resistance is on par with the original Healthways Scuba regulator.

I than took the third generation Healthways Scuba into the water, with the air ejector in place. This regulator breaths on par with a USD Mistral, and did so using either hose-mouthpiece system described above. It is quite noisy, however.

Next I used a modified AMF Voit 50 Fathom (downstream) single stage, and it was a very nice performer, on par with the third-generation Healthways Scuba.

Finally, I went back to the DA Aqualung, and enjoyed it for the last ten or so minutes of these dives. I even tested it by swimming hard underwater to try to build up an oxygen debt, but could not. The DA Aqualung provided all the air I needed. The air flowed smoothly, responsive to my inhalations, but not with the venturi that we are used to. So while it was smooth, it did take some minimal effort throughout the inhalation to keep air moving. This was a surprise, as before I had Broxton Chuck go through this regulator, I had relegated it to the collection tray. It had not been in the water since about 1974, when in Clear Lake I couldn't get enough air through it to sustain me without swimming on my back against a 1/2 knot current when ascending from about 50 feet. Now, I think it will come along and go diving this spring and summer. It is a quiet regulator, and the exhalation is very nice (USD two-hose regs always were superb at exhalation because of their duckbill design, right Duckbill?).

So that's the report. I'll do a bit more later, starting a new thread devoted to the DA Aqualung.

John

[nemrod]

A good DA is a very good regulator. The new silicone main diaphrams we have been using really help the DA a bunch, silicone cage valves make a noticeable difference as well and the new streamline cage valves seem to add a tiny bit. Does your DA have these meaningfull improvements?

Nem

[SeaRat]

nemrod said:

A good DA is a very good regulator. The new silicone main diaphrams we have been using really help the DA a bunch, silicone cage valves make a noticeable difference as well and the new streamline cage valves seem to add a tiny bit. Does your DA have these meaningfull improvements?

Nem

Nemrod,

No, mine is completely original, except that the mouthpiece is the curved Aquamaster type. I also did not use any cage valves, so there was no hampering of the air motion by the valves. The original DA Aqua-Lung did not have non-returns either, just a straight mouthpiece. The Navy divers fairly quickly replaced these with a Hope-Page mouthpiece which included non-return valves though. According to Rick and Barbara Carrier in their book, Dive, the complete book of skin diving, the Hope-Page mouthpiece was sold separately for $14.95 "to prevent water from entering the regulator in hoses." I have several LP diaphragms, and don't at this time feel the need to get a new silicone diaphragm (and there are some other reasons for me not getting them too). But the original Aqua-Lung did not have them either. In the U.S. Navy Underwater Swimmers' School, in 1967 we were not allowed to use non-returns with our Aquamasters. So I learned how to use these regulators without the non-return; it improves performance.

I dove today totally "vintage," using twin 50s with a 2000 psi fill (because of the yolks of the DA Aqua-Lung, and The Healthways Scuba, I decided not to tempt fate with a 3000 psi fill). The doubles had a modified military harness, without a waist strap and with a crotch strap that has the metal loop for the European weight belt. I used the weight belt (without weights) for the dive, and was completely neutral in the water. I entered and exited seven times in an hour to complete the tests. Each time I kept my mask on which started out as a Dacor Professional, then I switched to a Seamless oval mask with a silicone flex snorkel, which I didn't use. I was going to use Aqualung Professional fins, but forgot them and so used my Plana full-foot scoop-modified fins. I left them on the bottom each time I exited.

I'll have to say that swimming vintage underwater, sans BC, wet suit, weights, and with only the scuba, mask/snorkel, and fins, is a very sensual experience. You feel the water, and are very much more maneuverable than when wearing more gear.

This was really an evaluation of two inventor's regulators, Emile Gagnan and Richard "Dick" Kline. I had thought that Gustov de le Valle had designed the original Healthways Scuba, but may be mistaken:

www.portagequarry.com/legendarticles/miller_070705.htm

Anyway, my tests today showed me that Emile Gagnan was the preeminent scuba designer of his time, with the Aqua-Lung and even the Voit 50 Fathom downstream single stage, which I also tested today. His exhaust system was not equaled until the third generation Healthways Scuba (and this apparently was Gustov de le Valle's design). But by that time US Divers had come out with the DA Aquamaster. The DA Aqualung, as I dove it today, was a nice regulator.

John

[SeaRat]

I should point out that I usually do use non-return valves in the mouthpiece, and will be ordering some more from Dan. In the U.S. Navy School for Underwater Swimmers, they specified that we not use them for two reasons:

--They wanted us to know how to clear a completely flooded regulator.

--They wanted to harass us!

Since we were doing the maintenance on our own regs, when an appropriate time came (about two weeks into the three-week class, but before pool harassment time), we sneaked the non-returns into the mouthpieces of our regs. The instructors never did find out either.

It has been pointed out in a PM to me that these non-returns do improve the performance of the regulator, by decreasing the volume of air a suction effort must me made in. This improves the responsiveness of the diaphragm. It also improves safety by decreasing the volume of water that can enter the regulator, and making clearing the regulator much easier.

I have been watching Cousteau's film The Silent World[/B], where they use the DA Aqua-Lung regulator exclusively. They have the correct sound that the DA Aqua-Lung makes for breathing built into the opening scenes.

Chuck, what about your experiences with the DA Aqua-Lung? Could you share some of your thoughts here? It was Chuck's work that got my early 1953 green label DA Aqua-Lung, serial #6604, back working again as it should. I really appreciate his expertise with this regulator.

One last thought is that I have the original yolk on my DA Aqua-Lung. There are not too many valves that this yolk will fit anymore, as it needs to be very narrow. I have one USD double tank valve that will allow the DA Aqua-Lung to be used. I yesterday found out that my twin tank bar yolk, which connects two single tanks to make a twin, will allow me to put together my two single 71.2 tanks (Scubapro with Scubapro valves) into a twin tank unit that I can also use the DA Aqua-Lung with. I will be using this regulator this summer for underwater close-up and macro photography, which requires a quiet regulator.

John

[duckbill]

Good point on the non-returns. So, as far as improving breathing it would be the exhaust side that helps. The inlet side doesn't aide breathing in this sense, just prevents flooding.

Twin 72s in the river will probably give you a good 3 hours of dive time (less in a strong current, but still long enough to get a good chill on) for lots of pictures!
I hope you have a convenient way of getting that rig in the water without hurting your back. That's one heavy set-up. Be careful.

[mudhog]

SeaRat quote; "I'll have to say that swimming vintage underwater, sans BC, wet suit, weights, and with only the scuba, mask/snorkel, and fins, is a very sensual experience. You feel the water, and are very much more maneuverable than when wearing more gear."

Exactly!!! Close as I will ever come to the "manfish" ideal. Can't wait till Feb 10th, my next pool time. Even though I'm surounded by paddites I leave the snorkle in the bag.

[Broxton Carol]

John, the broXtons and DA navies will fit the post valves of usd origin up through about 1962 perfect. they fit the chrome ones that ran through the early 60,s on up a little snugger on the edge where the boss is rounded on the back. No problems though. You have a early broXton, but they are of all the same design. The navy DA type, and the DA navy were the epitome of the mark, as they had plated internal parts to prevent salt water corrosion. If you didnt wash out your broXton after each dive, watch out! I bought a very late DA Navy that was like new on ebay for 85 dollars. It had no hoses, clamps or mouthpiece. I opened it up, tuned it, and put on hoses etc from my original stock. It now is restored, and ready to try this season. Those contemplating buying a broXton to dive with should make sure its history has been fresh water use. Regs after about 18000 have the longer horns, that make it easier to clamp on the hoses, and use a conventional duckbull. the short horn broXtons which were the early ones up to about 18 or 19000 will function best with one of DANS replacement bills just like back in 1953! You just tie it on after removing the exhaust port. its easy. Just like original. These regs give all the air you need, and work so quietly. Only sometimes youll hear a faint ringing sound as you breathe, which is the spring in the center making the sound. The guy who taught me scuba was a factory trained us divers technician. I asked him about the sound and he related that the spring was what made it. he also said there was never a death traced to regulator failure, rather it was divers errors that led to their demise. I still own a broXton, and a black navy type DA. They are my favourites. ill say this again. While my royal is usually taken along for dive trips, it never gets wet. Why have to use second best. A broXton is all a real vintage diver will ever need.

[Broxton Coalition]

john, nice to see another thread about the broxton trademark regulator. i rarely see any posts, besides chuck's, about someone actully diving with these classic regulators. anybody else out actully diving with a trademark?
mike

[SeaRat]

mudhog said:

SeaRat quote; "I'll have to say that swimming vintage underwater, sans BC, wet suit, weights, and with only the scuba, mask/snorkel, and fins, is a very sensual experience. You feel the water, and are very much more maneuverable than when wearing more gear."

Exactly!!! Close as I will ever come to the "manfish" ideal. Can't wait till Feb 10th, my next pool time. Even though I'm surounded by paddites I leave the snorkle in the bag.

I've been using a snorkel since I first ventured into rivers in about 1957, even before beginning scuba in 1959. My first snorkel was a Voit flex-tube snorkel, blue and white. So I have always used a snorkel when diving, except in the U.S. Navy where they didn't let us use one. In the USAF Pararescue, we kept a snorkel, but strapped behind our leg knife, not on our mask (where it would potentially tangle with the risers or parachute lines during a para-scuba jump).

I think using a snorkel is a function of never really diving much from a boat. If you look at the Cousteau divers, they never had a use for a snorkel as they ascended the ship's or boat's anchor line, and rarely did they venture into the water without surface support and an anchor line in open water. In later years (1970s), there are photos of Cousteau divers snorkeling to release the diving saucer or when within a net pen with dolphins. But in these photos, they were either snorkeling or scuba diving without a snorkel, never scuba diving with a snorkel. But we found snorkels invaluable for our USAF duties in recovering the Apollo capsule, for instance, when we needed to put the floatation collar on the capsule.

So for me, a snorkel has always, even in vintage days, been a handy tool. When I dove the pool dives with the Healthways Scuba regulators and the USD DA Aqua-Lung, I first dove a Dacor Professional mask without a snorkel, then dove my Seamless oval silicone mask with a Dacor silicone flex snorkel. I used that latter combination for my pool work, as silicone is not affected by the clorination process in most pools (I found a pool in BC, Canada years ago that was purified by bacterial filters and sunlight only, so not all pools have chlorine). I do have a 1973 photo of myself diving a Dacor Dial-a-Breath regulator that I converted to an R-4, and I'm not wearing a snorkel in that photo, so I sometimes do and sometimes do not. That was a lake dive, and I like having a snorkel in my river/current dives.

Mike, I will be away from diving for a few weeks next month, and after that I'll get back in with more on the DA Aqua-Lung that has been resurrected after a 35 year hiatus from my diving gear. I really appreciate what Chuck has done for that regulator.

John

[duckbill]

searat said:

So for me, a snorkel has always, even in vintage days, been a handy tool.

Especially in vintage days, I would think, considering you can't swim on your back during a surface swim with a double hoser without risking salt water entry into the first stage. Long surface swims against wind and surface current in the open ocean can get scary, even WITH a snorkel.

Related question- Does a J-valved rig still holding back a reserve pressure allow one to swim on his back? i.e. Will the J-valve bleed enough air to the regulator to compensate for any air leakage, keeping the regulator pressurized?

[SeaRat]

duckbill said:

searat said:

So for me, a snorkel has always, even in vintage days, been a handy tool.

Especially in vintage days, I would think, considering you can't swim on your back during a surface swim with a double hoser without risking salt water entry into the first stage. Long surface swims against wind and surface current in the open ocean can get scary, even WITH a snorkel.

Related question- Does a J-valved rig still holding back a reserve pressure allow one to swim on his back? i.e. Will the J-valve bleed enough air to the regulator to compensate for any air leakage, keeping the regulator pressurized?

Duckbill,

The J-valve won't prevent water from getting into the box of the double hose regulator unless that regulator is equipped with non-return valves in the mouthpiece, which is another reason for the non-return valves. But it is the non-valves, and not the J-valve, which protects the regulator. Some J-valves, especially vintage, poorly maintained ones, do leak a bit, but usually it's a pretty tight seal. Also, for doubles and triples with a J-valve, the valve will only protect one tank, not the others. A vintage diver swimming on his/her back with a double hose regulator will risk salt water intrusion into the tank if the tank goes to zero pressure and the regulator is not equipped with non-return valves in the mouthpiece. I say this knowing that almost all vintage divers will use non-return valves, but this covers the few of us who sometimes (especially with very old regulators without venturi or air injectors) who do dive these without non-return valves. Realize that it is the non-return valves, and not the J-valve, that protects the tank except on a single tank with the J-valve in the up position and postitive pressure in the tank.

John

[duckbill]

Thankyou, John. I wasn't considering a scenario without non-returns. I was really just thinking about water getting into the 1st stage via a non-pressurized o-ring, and whether a J-valve would let air past to compensate for any IP pressure drop due to leakage if it hadn't been tripped yet. Never been a concern for me yet. I carry a snorkel and don't have to swim on my back, though it is more comfortable sometimes to do so.

Anyhow, a double set with a j-valve will maintain a pressure difference between the tanks at the rated reserve pressure until the J-valve is tripped and the air is equalized. I think I would feel the resistance before the one tank would get down to zero gauge pressure; I've never tried it. It only takes a few psi to be a positively pressurized vessel. In such a case I don't think water could enter. It would really have to be down to zero.

I'll think on this more. Thanks again.

[SeaRat]

The scenario that I envisioned is a vintage diver breathing his tanks to near-zero pressure, without tripping the J-reserve. He's on the surface, and flips onto his/her back, and gets a free-flow which takes the pressure down to zero in the one tank of a double set. This is me, with my double tanks. I am wearing a two-hose regulator without non-returns, but forget that and let it flood while on the surface swimming (no free flowing, so I forget). Then there is a problem at ten feet, and I dive down while trying to clear the regulator. I'm at ten feet, and have yet to trip the regulator. Therefore, salt water can and does enter this regulator.

This scenario above illustrates how salt water could intrude into a scuba tank. But this actually is more of a problem for single hose regulators, as they can also have a direct conduit into the tank at reverse pressures. With the non-return valves in place, any double hose regulator is better than a single-hose regulator.

John

[duckbill]

Okeedoke, now I see what you meant. Thanks.
I'll have to think about the "negative pressure" you mentioned.

But, MAN I must have been tired last night when I said this

duckbill said:

I think I would feel the resistance before the one tank would get down to zero gauge pressure; I've never tried it.

Duh! That's what a J-valve does! I've done it many, many times. I don't know what I was thinking. I guess I was trying to figure out how the one tank could get all the way to zero psig while in use. Your freeflow scenario clears that one up!

[duckbill]

duckbill said:

Does a J-valved rig still holding back a reserve pressure allow one to swim on his back? i.e. Will the J-valve bleed enough air to the regulator to compensate for any air leakage, keeping the regulator pressurized?

Now that I've had time to think this over, I keep coming up with the same answer.....No.
It took a little bit of thinking about "if this; then that", as well as studying Bryan's regulator cutaway photos (give credit where credit is due), but now I'm 99% sure that while on one's back with the mouthpiece on your chest, the diaphragm will be depressed and the 2nd stage open, as is obviously the case with a freeflow. It doesn't matter if the reg is being fed 1/1000 cfm or 1 cfm, both stages are open and the air will flow right out. So, even with a leaky J-valve, none of the air would build up sufficient pressure behind the 2nd (or 1st) stage to keep water from invading the valve/regulator interface o-ring as long as the diaphragm is depressed. It seems so clear now. Thanks for bearing with me. ;D