Voit MR12 rebuild a success!

[dead dog]

Took my boat out yesterday to test out the MR12 rebuild. Visibility was lousy and I couldn't find my fishing license. Ended up taking my GoPro instead of my speargun. Hadn't taken any video in a year or so but it was kind of fun getting reacquainted with the set up.

Now, I tend to pride myself with having everything all streamlined and looking proper underwater. However, on this dive I was having trouble with my mask leaking. See if you can tell why? Note: the red thingy is my mask lanyard. I had no idea it was positioned all wonky until I got home and reviewed the video. Oh well, no one's perfect. Mark

P.S. The MR12 was an amazing breather!

Entire video is 1min, 23 sec.

[vimeo]
View attachment 602443

Grandma! such big eyes you have. Grandma! such a big nose you have. Grandma! what's that in your mouth?

 

[John C. Ratliff]

Took my boat out yesterday to test out the MR12 rebuild. Visibility was lousy and I couldn't find my fishing license. Ended up taking my GoPro instead of my speargun. Hadn't taken any video in a year or so but it was kind of fun getting reacquainted with the set up.

Now, I tend to pride myself with having everything all streamlined and looking proper underwater. However, on this dive I was having trouble with my mask leaking. See if you can tell why? Note: the red thingy is my mask lanyard. I had no idea it was positioned all wonky until I got home and reviewed the video. Oh well, no one's perfect. Mark

P.S. The MR12 was an amazing breather!

Entire video is 1min, 23 sec.

[vimeo]
View attachment 602443

Mark,

If that is bad visibility, I want to come down and dive with you! For me, in Oregon, that was amazing.

I have several MR-12s, a MR-12 II and a MR-12 III. They are amazing breathers!

SeaRat

 

[Scuba Lawyer]

Mark,

If that is bad visibility, I want to come down and dive with you! For me, in Oregon, that was amazing.

I have several MR-12s, a MR-12 II and a MR-12 III. They are amazing breathers!

SeaRat

John,

I was using an INON Superwide lens on my GoPro. I had to get very close to my subjects (as in inches away) so the 8 to 10 foot visibility really isn't a factor. M

 

[rhwestfall]

Nice! Reminds me that I was gifted one. It sits on my "display shelf" at work. Now I think I want to explore it some more...

 

[lowwall]

As i recall the fuzzy distant past I recall the MR12 was a concept or design when Fred Roberts was with Voit
When he departed for aerospace I think Bill Oliver might have completed the design.

SDM

You'll be interested in Greg Barlow's article in the Summer 2000 issue of Historical Diver (page 32) which describes how Voit built the MR12 to try to be the first single hose regulator to meet NEDU requirements: http://aquaticcommons.org/15012/1/Historical_Diver_24_2000.pdf

"Two designers decided to buckle down and solve the dilemma that had plagued the manufacturers for years. Andrew (Jack) Chappell, and Fritz (Fred) Schuler of Voit/Swimaster took the excellent balanced diaphragm first stage that they had incorporated on the Dolphin II regulator and used it as the starting point. At that time, the balanced diaphragm first stage had an outstanding airflow with a corresponding small drop in intermediate pressure. When this design was extensively tested it was found that the pressure within the LP chamber would seldom drop more than 15psi, despite the workload. This design was such an innovation that it still stands as the primary engineering background for the latest Mares MR12 versions.

...
Perhaps the most important advancement was made in the basement of Jack Chappel's home in Fairfax, Virginia. As he pondered over the new additions he began to wonder if the size of the exhaust valve was not limiting the exhalation process. He enlarged the opening in the rear housing until a mouthpiece check valve from a Voit two-hose regulator would properly fit. It was close to 50% larger in volume than the standard size exhaust valve used at that time. It was also fairly common for many of the single-hose designs to breathe rather wet in any position other than the diver looking straight ahead. Jack then developed a tandem valve arrangement where the exhaust would first pass through a valve and then enter a small chamber where it would then exit through an identical valve. While this tandem design did limit the wet breathing effect, it had the adverse reaction of increasing the exhalation effort beyond an acceptable degree. (The wet breathing is still a problem with many regulators in an inverted position.) The new exhaust valve was also mated to an improved combination chin rest/exhaust tee designed to effectively channel the bubbles from a diver's field of vision. After hours of finishing up the modifications and gingerly tuning every feature, he took a day to visit the Experimental Diving Unit.

With much trepidation, Jack attached the reg under the watchful eyes of the naval operators and turned on the machine. As the breathing simulator increased the number of cycles and the depth rating, the results were read. The new design had passed with flying colors! The careful engineering and Yankee ingenuity had paid off.

The prototype was then sent to Voit's production facility in Santa Ana and the plans were drawn up for full production. The MR12 name was chosen to be the title of the first U.S. Navy approved single-hose regulator, the MR standing for "Military Regulator" and the "1" being single-hose; the "2" stood for the two-stage design.

Full production of the MR12 commenced in late 1970, and the diving world was soon to be changed forever. Voit sold the MR12's as quickly as they could manufacture them and soon their competitors were retooling in an attempt to match the performance of the new standard.

The death knell was sounded for the two-hosed regulator, and sadly just one decade later Voit/Swimaster disappeared from the market. Its legacy, the MR12 still lives on in Mares late incarnations."

 

[Sam Miller III]

@lowwall
FYI
I have know Greg Barlow for well over 30 years amd communicate often via E mail
Most recently regarding my new in the original box MR 12 .
Greg is a very fine gentleman and world class expert on Voit equipment
Keep on reading and learning

Perhaps of interest
HDS was establisbned almost 30 years ago for ONLY classical helmet diving
I was a member of the first and founding HDS Board of Directors.

I changed their direction of interest

I had the following appointed to the Board of advisors
Dr Andrus "Andy" Rechnitzer (google Andy)
Bev Morgan'
Bill & Bob Mistral (Div N surf )
Dick Bonin (SCUBA Pro)

They abd I changed the direction of HDS
I was the first and only HDS "Director of Sport Diving"

Thank you for the reference abd your concern

Sam Miller, III