AMF VOIT Swimaster Titan II MR12

[ew1usnr]

John C. Ratliff once bubbled...
The question came up on this thread about why use an old Titan regulator when you can get a new one. Well, the old are just as good as the new, probided they have been kept in good working order.

It only makes sense. Human physiology has not changed since the 1960's. A diver needed just as much air back then as a diver does now.

That is a fantastic idea about the water manometer, John. I love the basic simplicity of the arrangement. It is like something from an elementary school science project, but it would be flat accurate because you are taking a direct water column measurement rather that a dial gauge translation. I'll go to the harware store this afternoon and pick up some plastic tubing. 1/4" tubing would probably be best for accuracy because it would limit any capillary creep of the water up the tube. It will be fun to make a list showing the cracking and inhalation efforts of my various regulators. I'll post the results if everything works correctly.

Here is a web site that shows pictures of a home made water manometer: http://www.komar.org/bbq/mm/convert/mano/

The internet is great. Where else can I go to "talk" about a 1962 Voit regulator and find other people who knew what I was talking about?

 

[ew1usnr]

John C. Ratliff once bubbled...
That's very interesting information on Gagnan's contributions. I had no idea he was that active in scuba design.

I didn't undestand this quote at first: " ... the Voit ‘50 Fathom’ model. It was a single stage, fully balanced, downstream valve regulator that was the direct prototype of the US Divers ‘Calypso’ and “Professional Aquamatic’ models and the ancestor of most the SCUBA regulators still being produced today!"

I think that what he is saying is that the AquaLungs and Mistrals have upstream HP valves. The single stage Voit 50-Fathom HP valve may have been the FIRST regulator to have a spring balanced downstream poppet valve. That "modern" design eventually replaced the tilt-valve designs that were initially used in the single hose 2nd stages. I've read that too high a tank pressure will damage the upstream HP seat on a Mistral. A downstream 50-Fathom will just free flow untill the tank pressure drops to the point where it is balanced by the seat spring. The 50-Fathom is underappreciated and nice nice nice.

 

[Greg Barlow]

John,

Your information on the "cracking pressure" of getting the initial air flow to start in a reg is correct, but....

There is far more to a reg's breathing performance than the intial air flow. I can get any decent reg to flow at 1.0" of depth as measured from the front of the diaphragm. Getting the flow to continue in a smooth, fluid manner is an entirely different subject.

I worked as Rodale's Science Editor for a few years and had a hand in regulator testing of new models along with vintage regs that I had restored. When you see the breathing machine results of my vintage models you would understand that once the depth fell to below 70' or so then they just can't keep up with the flow patterns of modern regs. For an example, let me share this bit of info. A new Mares MR12 Akros three years ago was delivering the same breathing effort at 198' that a vintage MR12 II (1978 version) did at 90'. The MR12 II just couldn't keep up, and at 198' was delivering only around 60% of the gas flow that the new Mares product had.

The real killer on vintage regs was the size of the exhaust diaphragm. The effort needed to empty a large housing through a small diaphragm actually required more effort than that of the inhalation.

I don't mean to knock the vintage gear. I LOVE THEM! I make vintage divers every year with both double and single hose regs. They are simple, robust, and flat out neat. But, they perform like an asthmatic when it comes to any real depth or effort.

Best Wishes,

Greg

 

[ew1usnr]

Hello, Greg.

You are correct. I admit that were I to plan a dive to 200-feet (or a hard dive deeper than 100-feet) I would choose my Poseidon Odin over my Voit Titan-II. But, at 60-feet ...... I prefer my Titan-II !!! It breathes smoother and delivers plenty of air for that depth.

Question: Was there a Titan-"One"?

 

[quimby]

Greg are you saying the IP failed(dropped and cannot supply flow as the III due to path etc) or is it the exhaust restriction that is the diff. I still use mine past "rec limits" and in a comparison I really didnt notice much diff. Im still not a air hog but should have been some diff noticeable.
PS Didnt do much at all with the little gem but have to get the courage up and look behind the liquor locker in the abyss and see what is hanging around.

 

[John C. Ratliff]

Greg and all,

I fully realize the limitations of a water manometer taking a reading on the surface. And what Greg says is probable true most of the time (though I will challenge some of it below).

I investigated a diving fatality in 1987 where the inhalation resistance, using my surface-based water manometer, was measured and was one of the 8 contributing factors for the fatality. I would like to read to you what I wrote on May 2, 1987 about the fatality connected with the breathing resistance. He was using a Scubapro

"Mark V first stage updated with a Mark 10 cap, and an adjustable second stage of the same manufacturer. The second stage was without its exhaust tee; the 1st stage yolk retainer was loose. The second stage adjustment was tightened all the way down. The inter-stage pressure (tested after removing the low pressure inflator hose) was approximately 135 psi, which is at company specifications. Upon ititial placement of the regulator on the test tank, there was a significant first stage air leak at the yolk retaining assembly. The "Technical Manual for Scubapro Regulators states the probably cause as "a. One of two pneumatic yoke piston O-rings is damaged. b. Damaged yolk retainer O-ring." and goes on to say that the suggested remedy is to "Return regulator to dealer for repair." I inspected this O-ring, and it was dry (unlubricated). (In order to inspect this O-ring, I removed the yolk retainer, which could be unscrewed by hand. I also removed and replaced the seat retainer to see whether the seat was damaged; it was dirty, but undamaged.) The regulator did not leak with negative inhalation pressure...

2. Possible regulator malfunction--First Stage: The first stage retainer for the yolk was loose, and leaked when we first placed it on a cylinder with 900 psi in it...this probably was not a factor until the end of the dive, and may not have happened at all. However, it could also have caused a steep drop in air supply available at theend of the dive.

3. Possible regulator malfunction--Second StageO: The regulator was missing the exhaust tee, which could have allowed water seepage into the second stage housing. This is especially possible due to the high suction pressure needed to open the demand valve (see below)...

4. Regulator malfunction--Second Stage: Breathing resistance was very high. The regulator was leaking air prior to the dive, and the adjusting nutwa was screwed down by Mr. XXXXX to stop the leak. It was screwed all the way down. The following measurements were taken using a home-made open tube manometer:

Exhalation Resistance:

Cracking: 2 centimeters H20
Full Exhalation (peak): 8 centimeters (3 inches) H20

Inhalation Resistance:
Cracking: 10-12 centimeters (4-5 inches) H20
Peak Inhalation: 26-28 centimeters (10-11 inches) H20

This can be compared to the SCUBAPRO chart for specifications on this first stage, which shows in Figure 7 a 1-4 inches of water breathing resistance for a well-tuned regulator of this brand. This would have caused quite a fatigue factor throughout the dive.

In short, the water manometer could easily be built, and used, to determine whether this regulator was fit for diving. I have used them to determine both cracking and peak inhalation/exhalation resistance at the surface at various tank pressures. So they are a valid tool, if their limitations are known.

I'll save my other information for a later post, as I am hungry, and breakfast awaits.

SeaRat

 

[Greg Barlow]

Quimby,

The entire work of a breathing cycle from intial air flow until the second stage is completely emptied from an exhalation is considered the total work of the regulator. The US Navy calls for a supply pressure of 1,500psi and for various workloads to be completed at preset depths. The three breathing rates are 37.5 RMV (respiratory minute volume), 62.5 RMV, and finally 75 RMV. The lowest figure simulates an average diver cruising along at a leisurely pace and keeping their heart rate at a pace where they shouldn't feel winded. The second is that of a diver working at a hard pace, such as swimming into a fairly strong current. I equate this to someone running a mile at a pace where talking would be difficult. The final is at a rate where there is enough available gas to meet the needs to two divers at one time.

Now, the tough stuff...This is all pretty simple for any reg at 50' or less. The breathing rates must all pass within set parameters (usually 1.5-3.0 joules depending on who's qualifications), at the following depths: 132', 165', and 198'. The US Navy uses 1.5 joules as a "Class A", while the Europeans call for 3.0, but only using a pressure of 750psi. Still, it is easier for a reg to pass EN250 standards than to earn a Class A rating.

The sad news is that of all the vintage regs tested from my collection, the only one that could meet Class A at 132' was the US Divers Calypso VI which has a very large balanced piston first stage, and a venturi system in the second. It barely passed on one simulation (failed by a small amount on two other trials), and wasn't even close when the 198' was attempted. My favorite, the MR12 ('73 edition) barely failed the 132'. The Little Gem gave up the ghost at 70'! It was stuttering and stammering while its tiny unbalanced piston and tilt valve were working overtime.

Now, remember, this does include the exhalation effort. I had
replaced all the soft parts and tuned them specifically to manufacturers standards. Trust me, I wanted them all to pass with flying colors.

One fascinating thing is that the simulator records the IP while the reg is working. Many of today's top models can supply gas under heavy loads and still only drop around 10psi. The oldies would regularly drop 20 or more. They simply weren't designed for that type of work. Heck, when I started diving in '75 many of us still didn't use an octopus. When you consider that even today you should be diving deeper than 150' or so on air, then the performance of the oldies does look pretty good.

In closing, the amazing thing is that there are some regs today that can actually beat the ANSTI breathing machine. A few have met Class A at 198' with the EN pressure of only 750psi!

My Mares MR12 regs are certainly not the best of the bunch. But, they are extremely simple to maintain, and extremely robust. Just like their "grandfathers"!

By the way, I took one of my original MR12 regs to 140' just last summer (on a separate pony bottle) and it breathed rather well. Of course, I wasn't expelling much effort either.

Dive safely and often!

Greg

 

[Greg Barlow]

John,

I agree about checking the cracking effort of a reg. I routinely check mine at the surface. I know the mark on my regs is at 1.5" of water, so it is a great way of screening the reg. I also always check regs that I rebuild in the same manner. Sadly, there are techs who never do this. Some brag about how fast they can rebuild one (parts changers), while I "confess" to spending more than an hour on each one. I never fail to do a water leak test, and leave the reg pressurized with the tank valve turned off to test for any minute leaks. Just yesterday, I left one pressurized will all hoses and accessories for three hours. The pressure on the SPG only fell around 40psi, while the lockup pressure was exactly the same (140psi).

My dive buddies give me a rough time about being so anal with caring for and testing my gear. It's funny, though, as they ALL want ME to rebuild their regs....

After starting in '75, I've never cancelled a dive yet due to a piece of gear failing me. A stitch in time save nine!

Greg

 

[John C. Ratliff]

Greg,

Just a quickie...did you ever test the Royal Aquamaster to the specs listed in your post above? I'd be interested in knowing, because for many years the US Navy would not allow single-hose regs into their inventory because of the exhaust restriction problems.

SeaRat

 

[ew1usnr]

And I spent the afternoon testing my regulators for peak inhalation effort (see attached photo). My DA AquaMasters pulled 3" of water column. I guess that I'll have to work on them some more. How low should I be able to get an AquaMaster down to? My Voit Trieste did better at 2 1/4" of water column. My Voit 50-Fathom did best with 2" at 400 psi tank pressure and 1 1/2" at 2300. For comparison, my US Divers Conshelf 21 also showed 1 1/2" of peak inhalation effort. My Voit Titan II did better than the Conshelf with only 1 1/4" of water column.