Royal Aquamaster Tank Pressure

[time2dive]

Today I dove with my birthday present....A Royal Aquamaster, I finished rebuilding it last week. It breaths better than my Mistrals or my DA Aquamasters. I know the the unbalanced regulators do not like tank pressures higher than 2400, since the RAM is a balanced regulator and basically has the same seat as a Conshelf, do they get grumpy at tank pressures above 2400?
I need to rebuild my J valve it is not shutting off at low tank pressures.
70 feet, 50 minutes water temp 78

Tim

[YankDownUnder]

I dive a Royal Aqua Master too. I use it on Faber HP steel tanks at 232 BAR (3410 psi). I feel that having a J valve is a good idea and installed them on these modern tanks. (The burst disc assembly had to be changed of course.) With the long yoke on the Royal Aqua Master, I can use a banjo fitting. It allows me to use a transmitter, thus keeping down the number of hoses. Batteries fail though and my Suunto uses two of them...thus a J valve.

Not long before I left Salt Lake City in 2004, the diver across the street from me, had a dive buddy die. She was a medical doctor, in her 50s and very experianced. They was seperated in cold, murky lake water and it appears she simply ran out of air during a safety stop. The J valve would have reminded her of her low air supply. Most people would say J valves are antiquated, but I still think they are a good idea, even with a pressure gauge.

[duckbill]

My LDS owner once said, "Anyone who would still dive a J-valve is stuuuuupid!"
He doesn't like it when I tell him he can't disable mine! But he's a pretty good egg, and entitled to his opinion.

More in line with your question- I don't have a RAM, but the consensus seems to be that RAMs, being balanced, can take whatever a modern, balanced regulator can, AS LONG AS THE YOKE IS ALSO DESIGNED FOR THE WORKING PRESSURE. I believe the yoke is the limiting factor.

[luis]

The 1976 US Divers repair manual includes the Royal Aqua Master and it specifies its operating pressure to 3500 PSI.
The RAM first stage is the same as the Conshelf, Titan, etc. As mentioned above, the yoke would be the only limiting factor.

The original long yokes can handle 3000 PSI (and it seems that YankDownUnder is using it to 3410).

The only problem with using the original yoke at higher pressures is that it tends to flex more and you increase the risk of blowing an O-ring. When the yoke flexes a small gap is opened which can allow the O-ring to be extruded. The heavier yoke flexes less and once you tighten it properly, there is very little chance of blowing an O-ring even at higher pressures.

[Captain]

"They was seperated in cold, murky lake water and it appears she simply ran out of air during a safety stop. "

How can someone die by running out of air at what I asume was a 10 or 15 foot safety stop?
Could a person be more afraid of missing a safety stop than surfacing because they are out of air. Some of my diving is in a lake that at its deepest is 15 feet and sometimes I will breathe a tank completely empty before surfacing.

[nemrod]

I don't know how an experienced diver could drown at 15 feet either but strange things often happen. Maybe she got disoriented/distracted or there was some other factor involved. I am sorry to hear that.

I think the standard duty long yoke is fine to 3,000 psi. I have taken measurements using a dial indicator and the flex is within the elastic limit of brass per a materials manual I got somewhere around here. The flex is about three times that of the heavy yoke however. I think it was like .05. Measurements of the yoke--before and after--of a new standard long yoke before applicartion of 3,000 psi and after revealed a lengthening of about .003. This was a permenant distortion but subsequent applications of pressure resulted in no further deformation. I was not able to measure any deformation of a heavy yoke.

Perhaps another person can take similar measurements and report back. I think it is pretty much a non issue up to 3,000, beyond that, for me, I would worry over O ring failure but aside from worrying I have not actually observed such a thing when the yoke was properly installed with a good O-ring.

Tanks were routinely over filled back in the day to 2,500 or 2,600 or more psi so we are talking about approximately 400 or 500 more psi and most of those regulators back then had much lighter yokes than today. Not really enough to fuss over.

James

[luis]

Hi Nemrod

I agree that most yoke flexing is basically within the material elastic range and therefore is not a structural issue.

I am only referring about any yoke flexing that occurs (and some will always occur, even if it is not visible) will increase the gap between the valve and the O-ring seat. As this gap grows there is an increase chance of blowing/ extruding an O-ring.

If you read on ScaryBoard (I mean ScubaBoard) the yoke connection seems to have gotten a bad reputation for blowing O-rings. IMHO it is because of lighter more flexible yokes improperly used at higher pressures (in combination with operator error).

With the newer small O-ring valves, the regulator presses directly onto a metal edge leaving no gap for the O-ring to be extruded. The only possible failures can occur if something is worn, permanently deformed, extremely flexible yoke, or operator error.

[SeaRat]

Tanks were regularly filled in the U.S. Navy to 3000 psi in 1967, and the DA Aquamasters we used had a standard (not long) yolk. We never had any O-ring problems with them. Here's a photo:

John

[YankDownUnder]

Re: Tom and Nemrods' comments.

The computer she was wearing was taken by the local Sheriff's Office and that was their conclusion after down loading the data. I worked for a different Sheriff's Office, so I did not access the report. Gauges are great....if you look at them. My reaction was much as yours when I saw the absurdity of divers noticing they were out of air in the film 'Into the Blue' then looking at the pressure gauge and finding it empty. Of course that is Hollywood. However, Captain E.J. Smith was also experianced and had been at sea for 30 years without ever having a problem. He had just one. His ship hit an iceberg. It was called Titanic.

[Deleted]

Just to throw in my 2 cents......I dove my late 60's era RAM with the long yoke using 80 cu al tanks early last June at Cozumel.......they were filled to 3300 and I had no leakage around the yoke......my hp line to my SPG sprung a leak as I was gearing up for the third dive and I quickly replaced it with the spare off my Tekna.......however, I experienced no leakage at all on any doublehose dive around the yoke/valve connection.......all the tanks I used, were 80's filled to 3300..........