Vintage Double Hose

I just opened a chrome 50 Fathom I recently acquired. Other than being moved around on a shelf for 56 years I don't think it has ever seen water. The hoses and mouthpiece are original. Although in great cosmetic shape they are toast for actual diving. This is my first foray into rebuilding this type of downstream design so I'll likely have some questions for the experts as I go along. Mark

Wow. That one is a treasure. Congrats on a great find. It's been awhile since I rebuilt my Chrome 50 Fathom but Greg Barlow sent me an article that ran through the whole thing. I think its posted on the forum. First thing I notice is that your Venturi port is pointing this way instead of down the air hose. That will be one of Greg's recommendations... Rotate it to point directly into the breathing hose.

I think there's an interesting mystery around the 50 Fathom regs. The downstream airflow can be tuned for super easy breathing. Mine will free flow with a kiss and release of the mouthpiece. If it worked so well, why did Voit discontinue it after only two years? And adding to the mystery, why are they all configured with the Venturi pointing away from the breathing hose? Were they trying to De-Tune it for some reason? Maybe sabotage the performance so it wouldn't make the Voit Navy look bad? Even so, why would that make any sense?

The 50 Fathom downstream single stage is the only double hose that Voit got from Emil Gagnan that wasn't also offered by USD. This makes it a highly desirable acquisition for Voit fans. And unlike the highly desirable Royal Mistral from USD, the 50 Fathom is easy to get up and working... And it WORKS WELL! I really like my 50 Fathom regs and dive them regularly.

SurfLung wrote:Wow. That one is a treasure. Congrats on a great find.

Thanks Eben! I think when I put it back together I'll rotate the body so the venturi faces down the inhalation horn. I heard that can improve performance. I'm open to all advice. I am assuming I should test lever height on a full 2250 tank given the fact it breathes easier at higher pressures (I think). Mark

SurfLung wrote:Greg Barlow sent me an article that ran through the whole thing.

If you know where to find that article i'd love to read it. Didn't see it in the Manuals section.

Ok, so I found two diagrams for this reg. The second diagram has (in red oval) 2 gaskets, a seat and a sleeve. The first diagram does not have those parts. My regulator looks like the first diagram (without the extra parts). What gives? Are these for different year 50 Fathoms? I figure someone out there in DH-land has an answer. Thanks, Mark.

I think Greg's instructions and advice are in one of my posts:
viewtopic.php?f=4&t=6870&p=58237&hilit=VCR2#p58237

The seats on both of my VCR2s were sealing fine and I heard they were hard to work on... So, I didn't take them apart. I don't think there are readily available replacement parts for those. Bryan has a kit with springs and screws but I don't think it has the seat. Anyway, I left well enough alone and both of my regs are great breathers that I have been using a lot for the past few years.

Here's my chrome VCR:

Thanks Eben. Great information in your thread. It looks like mine is a 1961 50 Fathom with a 1959 downstream mechanism. Appreciate the link. I will report back when I get the reg back together and working. Your reg is beautiful! Mark

Ok, got it apart and it was a newer version seat assembly (well, new as in 1961 vs 1959 ) The thing was in such pristine condition there was nothing to clean. The seat was perfect.The two phenolic washers didn't want to come out but looked in really great shape so i left them in. We'll see if it leaks or not. Eben, you are correct about it being difficult to work on. Getting the pin back in was a real comic effort. Half my attempts led to the spring sprunging sending all manner of small parts flying off my dining room table (/workbench if the wife has already gone to bed). Finally got the pin in and the seat assembly/spring is now a functioning unit. On to the rebuild.... Mark

Sorry about the late response to this topic. I’m currently in Mexico, and have sketchy internet capabilities. That is a wonderful addition to your collection!

Once properly rebuilt, the reg will need little service. One of my chromed versions was rebuilt nearly a decade ago, and has almost 200 dives on it. Mechanically, the design is very robust.

In my opinion, the positioning of the orifice isn’t critical. The factory setting is with the smallest port facing the inhalation horn. As the hole is smaller, the gas velocity should be higher than with the larger port. I have made several dives with the same reg set in the two different configurations; and to the same depth range of 100-120fsw, and couldn’t reliably discern a difference.

The physics behind the variations will need to be a topic of discussion with Luis and I during our travels to Truk Lagoon this February.

Greg

Thanks Greg,

U da master! I read your prior posts in Eben's thread and they were spot on and very helpful.

The real question is whether Luis discussing engineering and physics in Truk makes the trip a write-off?

Finished the rebuild. Breathes fantastic.

Uhh, that looks like one of the levers I made for Bryan a long time ago.

Douchebag wrote: ↑

Wed Jan 10, 2018 7:43 pm

Uhh, that looks like one of the levers I made for Bryan a long time ago.

Interesting. When I opened this puppy up the first time I had to take the standard 7 c-clips off first. The main diaphram was an old two-stage one with the prongs flattened. It looked like it hadn't been removed ever. The hose clamps were original voit ones. The hoses, mouthpiece, one-way mushroom valves and duckbill were most definitely all original and unusable. I ended up having to replace the 2 phenolic washers as they were a leak point. Odd that someone would replace only the lever?

CORRECTION: This one had a band clamp, not C-clips. It was an original band clamp as it did not have any cut-out for the horn.

Greg Barlow wrote: ↑

Fri Dec 15, 2017 11:31 am

In my opinion, the positioning of the orifice isn’t critical. The factory setting is with the smallest port facing the inhalation horn. As the hole is smaller, the gas velocity should be higher than with the larger port. ... Greg

Hey Greg,
- This statement threw me into a personal turmoil... Questioning the meaning of my life. I was of the opinion that you told me to position the large orifice facing the inhalation horn. I did both my VCR2s that way and they are fabulous easy breathers. Kind of proud of myself for learning that tune-up trick. So I went back and read that thread a bit. And here's what you said back then, "I do recommend setting the large orifice toward the inhalation horn. " I think Allan told me to do it that way, too.
- And also, I had a personal observation that when I pressed the lever, a lot more air came out of the big orifice than the smaller ones... Path of least resistance, I suspect. Which supports positioning the big orifice toward the inhalation horn.
- I don't mean to put you on the spot but this large orifice position is part of the fascination of the whole 50 Fathom topic for me. Besides MY two regs, I've seen pictures of the insides of others and NONE of them have the large orifice positioned (properly?) facing the inhalation horn. Considering the mysterious discontinuance of the VCR2 after only 2 years in the Voit catalog, I like to imagine there was some sort of conspiracy and the regs were perhaps sabotaged by facing the SMALL orifice toward the inhalation horn to detune them so they wouldn't out perform the Voit Navy?
- Yeah I'm probably off the wall on that... But I haven't found any other published reason for discontinuing a regulator that works so well and appeared so prominently in so many Sea Hunt episodes... People HAD to be asking for it at the dive shops.