Can a J valve save your life?

[standingup]

Using a double hose with a j valve could train you how to respond in an emergency. Diving j valves we all got used to out of air situations (everytime we dove) Suddenly (if you were not paying attention) air was harder to draw. A simple pull on a rod gave us air again. My point is spend some time diving in a pool or shallow dives without all the extra hardware a Phoenix allows. How many times have you K valve divers( since you were certified )experienced or practiced out of air situations. Once ? maybe twice ?
Believe it or not its kind of fun not knowing when your dive will end. If I'm wrong set me straight.

[swimjim]

I don't use a J valve because they can accidently trip and be use less. I learned how to dive without an SPG. I dove for a long time with one. When I got into double hosers, I dove them on independant doubles with a single hoser for back up. For myself, I know I can do forty minutes at fifty feet on a steel '72 and suck it dry. Therefor, I limit my dives to about thirty minutes which gives me a comfortable reserve. If I dive deeper or shallower I adjust accordingly. A dive watch or a computer used as a timer is all I require. No need for the old J except for looks maybe.
As far as practicing OOA, I haven't done it in twenty eight years or so. I put alot more emphasis in not running out of air in the first place. The only excitement I've had in the last several years were freeflows that happened deep. In that event you just keep your head and sip air as you return to the surface. I cured the problem by replacing the plastic reg with a real one. My Xstreams never have trouble. I don't generally take my double hosers past about sixty feet and I can do a CESA from there if need be.

Jim

[duckbill]

Believe it or not its kind of fun not knowing when your dive will end.

Some say that with experience you should know when your dive will end. I can't say I'm at that point. I can have a rough idea, but I don't think anyone can be dead on unless they go through the same routine for each dive. Otherwise, there are so many variables involved. Variations in fills, depths, and exertion all play major roles in changing the timing. Even temperature can contribute, as can caffeine and who knows what all.

As for the J-valve saving lives?....Sometimes yes, sometimes the opposite. Here is what I said in a previous thread:
I just had my first J-valve malfunction last week. My set-up is an old 1/2" USD manifold on twin-38s. Typically, the J trips to give 400 psi equalized pressure, and the cylinders "sing" to me as I get down near the time to trip. When the malfunction occured I noticed that the dive was lasting longer than usual, and that the cylinders weren't "singing". I kept watch as the gauge metered near 100 psi and got in a position near the surface since I suspected trouble. When I felt the resistance, I tripped the valve and the cylinders equalized to only 180 psi! Up to the surface I went and ended the dive. Had I not been familiar with my own set-up or been less experienced I could have been in trouble.

[Nemrod]

I know it is blasphemy but I have to tell you I am not a J valve fan, never was, never will be. My old Claypso would run a tank flat empty and so will my RAMs, in fact it will dang near but a vacuum on the tank. If your busy with an active dive you just may not notice the subtle change in breathing that high performance regulators deliever. I learned and dove for several years with J valves and had them tripped accidently numerous times. It got so that I had a habit of swimming with my hand on the J rod to make sure it stayed up after one particular eye bulging moment impressed upon me the need to make sure that lever stayed up.

While some may think the spg is not vintage I dissagree, they were around in the 60s and so were the banjo fittings so therefore I think they are vintage acceptable and especially if it is a vintage spg. I have three SeaVues and one very nice vintage USD guage.

Mike Nelson seemed to always know how much air he had, I never could be exactly that sure. Certainly some people develop a very good sense of air consumption but I suppose I am not one of them.

I think a good J valve with the reserve pressure bumped up is a good and simple set up for shallower dives but below 60 feet or so I really want an spg--call me a wuss--I don't care--I have my limits and I am not counting my life on one when diving at more extreme limits.

James

[standingup]

I also like SPG's and feel they are vintage. But I'm promoting not finishing a dive @ 500 or 600. Instead go ahead and use the SPG or experience to know when the dive is about to end but continue (only in shallow water dives) to dive until its necessary to pull your J valve. The "eye filling mask" reaction can change to a "darn out of air again" shrug.

[crimediver]

I supervise an underwater criminal investigations team. We do search patterns in the mud, dragging lines as we lie prone on the bottom. Our search technique is similar to making snow angels. We are normally diving black water and the mud we stir up is inpenetrable.. Every second pass I try to check my guages. Often I cannot read the guage despite pressing it and a flashlight against my mask. It is not zero viz diving, it is negative viz diving. I use j-valves on aluminum 80's to give me a safety margin as it is really hard to read a guage unless you swim out of the search area. This is not a practical option. A lot of the mud we dive in coats everything we wear with a film of mud that has to be wiped off, mask and guages included. A j-valve is well suited for this work as it adds to the diver's safety. That is also a big reason the US Navy still mandates J valves on their tanks.-Jim

[21]

In California diving we have kelp and other entanglements to contend with so J valves were a problem.

1) We always disassembled the J valve and reversed the cam. With this change the J rod had to be pushed up to engage the reserve
2) The pull rod was tossed. To activate the reserve it was necessary to reach over the shoulder and pull the valve lever up. It always worked.

I will guarantee you that if you are at depth and running low on air and need ot reach over your shoulder to activate the J valve You can do it. I will also guarantee that if required your arm will grow at least 6 inches to reach the valve
__________________________________________
Crime Diver,

Use a clear cone in limited vis.

When I was involved in limited vis diving packets were obtained of clear H2O from a hospital supply company to make clear cones. Today you can possibly used a clear zipp lock bag

The the H20 Is placed on the object and the mask is compressed on the H2O bag aka "clear cone" and the object is viewed through clear water. Works great! Try it!

You may encounter problems in the Uee-goooie sticky stuff often found in harbors and need to revert back to the Mark 1 hand ID.

Good luck and becareful under there.
________________________________________

Mar Mac introduced the first SPG in 1954--had some serious problems. Never popular.

The SPGs ecame popular with the Sportsways Navy unit--It had a very flat breathing curve that gave no warning of low air. Sportsways Ided the Mar Mac problems and produced a very fine unit...Others followed them.

21

[crimediver]

Good idea. I have heard about it and need to try it. I wonder how a cyalume chemlite in the bag would work? When I am looking for relics, etc in those conditions and am not having to stay on a search line, I use a mask with a small compass glued to the inside of the mask with a small (1") chem light attached to it so I can keep my bearings.

[dhaas]

Amigos,

Since getting back into vintage gear I have used j-valves on two 71.2 steels from the 1960-70 era. I KNOW they work because Ron Yanega and I have used them (and dissassembled one) before pool dives, and then in our local quarries and at Sand Dog II and III.

Part of vintage diving for me using the old single stage Mistral, a Conshelf VI and my recently acquired diaphragm Calypso is keepng it simple. My newest Calypso has the "pin" gauge in the HP port and I'm trying it out in the pool Dec. 13th

In my 37th year of diving, and with over 2,500 dives I do the same thing with my j-valve rod I do using a SPG when diving modern gear. I CHECK IT EVERY 3 - 5 - 7 MINUTES!!! I did this when I had my first MR-12 single hose, Voit Safety Vest and original Voit j-valve tank. Can't remember if this was drilled into my head by my LA County / NAUI instructor friend, or whatever, but I NEVER have had a j-valve knocked down. I do like Sam Miler's recommendation, and as I acquire some old low pressure tanks to use with my vintage regs may try this change.

So my recommendation if you want to dive one is make sure your j-valve works, dive often enough and practice by letting it run down so you'll know the "feel" of that last 300 PSI.

Plus get off the couch and go exercise.....Be a better swimmer. Like Jim I know I could easily still do an out of air ascent from 60', and likely deeper.

YMMV,

dhaas

[standingup]

My newest Calypso has the "pin" gauge in the HP port and I'm trying it out in the pool Dec. 13th Smile

You sure you want to use that date.

[dhaas]

Standingup,

Yeah, Dec. 13th is a WEDNESDAY

Plus I'm not superstitious......

dhaas

[21]

Some years ago there were a discussions about the inventor of the J valve. Apparently no one, at least at that time, knew for certain who invented it or where it was invented or actually when it first appeared as componet of the diving world.

There was speculation that it came from both US ( we are gaget types) from France and from Canada. No one knew for certain. Some suggested it was a Gagnon contribution, others maintained it was like Topsy and "jus grew da way."

I certainly don't know and haven't taken the time to reserch it to its origin which was about 1952 -3.

Any thoughts?

21

[dhaas]

Since I was born in 1953 my memory is foggy about who and when the j-valve might have come into being for scuba

LOL......

dhaas

[captain]

Here is a part of an CFR from OSHA about the J valve.

http://a257.g.akamaitech.net/7/257/2422 ... 10.426.pdf

[YankDownUnder]

I have J valves where needed and just check every five minutes, like I would a pressure gauge. I also use banjo fittings and am looking forward to using small yoke regulators with Bryan's new ones.

I am told that there is a requiremnet here in Australia, to disable J valves. There are still a lot of them around, but they don't have the pull rods and are just left down with modern regulators. The rationale is that you could run out of air while still having 500 psi. Australians are big on rules. No one follows it. A J valve without a rod is almost pointless.

Police here insisted on Pin gauges that were made here by AirDive. They were developed by AirDive to use like a hose gauge, but were 4 inches long. Healthways copied then after they saw an Sea Bee model. You could just feel them in black water. Now the police have reverted to inverted tanks, so they can decant. Of course they use AirDive (dare I say it) single hose regulators. It is interesting to see this, because it was the sytem on the 1953 vintage Porpoise. Cousteau's team used triples and the last cylinder was valved on the base as a reserve. History repeats itself.