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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
beel82
Skin Diver
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First Name: Whitney
Location: Issaquah WA

50 Fathom w/ Mistral Internal??

Sun Oct 06, 2013 2:38 pm

I just struck gold at a Garage sale. A blue 50 Fathom with mistral internals!! Thats kinda odd? The old man I bought it from said it was his late brother's who owned a dive shop somewhere in central Florida I believe. Was this a common modification? I have heard the 50 Fathom, although similar in design, was rather lacking in performance compared to a mistral.... dont really understand the economics of the modification but oh well..

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SurfLung
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Re: 50 Fathom w/ Mistral Internal??

Mon Oct 07, 2013 9:31 am

- Is it a blue painted, metal cans, Fifty Fathom? Because they made a blue plastic cans model with Mistral internals later... See http://vintagedoublehose.com/index.php? ... icle&id=96.
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

beel82
Skin Diver
Posts: 29
Joined: Sun Feb 06, 2011 10:45 pm
First Name: Whitney
Location: Issaquah WA

Re: 50 Fathom w/ Mistral Internal??

Mon Oct 07, 2013 1:49 pm

Its the blue painted can. My guess is they had a damaged mistral regulator laying around and decided to " upgrade" :D the 50 fathom. Its kinda neat. I got some voit 38s with a Viking manifold as well. Can't wait to get it in the pool.

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Greg Barlow
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Re: 50 Fathom w/ Mistral Internal??

Sun Oct 13, 2013 7:57 pm

beel82 wrote:I just struck gold at a Garage sale. A blue 50 Fathom with mistral internals!! Thats kinda odd? The old man I bought it from said it was his late brother's who owned a dive shop somewhere in central Florida I believe. Was this a common modification? I have heard the 50 Fathom, although similar in design, was rather lacking in performance compared to a mistral.... dont really understand the economics of the modification but oh well..
Voit did produce an upstream version of the 50 Fathom. It was known as the V55 Blue 50 Fathom. However, the "Mistral" mechanism had notable changes. The lever plate was completely different as was the appearance of the venturi nozzle. If your particular reg has 4 machine screws on the lever plate, then it is an original. The USD Mistral design used two screws, along with a threaded shaft protruding from the plate. The Voit nozzle had a shape somewhat resembling the end of a mechanical pencil.

The downstream design actually performs very well when properly tuned. It can be a difficult reg to service, as annoying leaks are not uncommon. I have rebuilt a significant number of them over the years, and it is my favorite DH reg.

If you post a picture of the internals, I can verify the mechanism.


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beel82
Skin Diver
Posts: 29
Joined: Sun Feb 06, 2011 10:45 pm
First Name: Whitney
Location: Issaquah WA

Re: 50 Fathom w/ Mistral Internal??

Mon Oct 14, 2013 8:29 am

It has the two machine screws and nozzle/lever configuration identical to my Mistral Stream Air.

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Greg Barlow
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Re: 50 Fathom w/ Mistral Internal??

Wed Oct 16, 2013 8:12 am

beel82 wrote:It has the two machine screws and nozzle/lever configuration identical to my Mistral Stream Air.
That settles it.... An USD upstream unit was installed. Does it have the short Stream Air nozzle, or the Mistral version?

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Greg Barlow
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beel82
Skin Diver
Posts: 29
Joined: Sun Feb 06, 2011 10:45 pm
First Name: Whitney
Location: Issaquah WA

Re: 50 Fathom w/ Mistral Internal??

Wed Oct 16, 2013 8:52 am

Its the mistral version. Did the Polaris 50 have mistral guts? I havent found anything in depth other than that they were very similar.How similar?

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