Question Hi guys. I'm thinking putting a BOV on a vintage Voit Trieste 2 double hose regulator.

[Trucdiver]

The Trieste II has been upgraded with a larger can and diafram from the Scuba museum. I have large bore Dräger hoses and DSV on it.
It breaths really good.
Had to 3D print a couple hose adapters for the horns. To be able to use the dräger loop.
Come out good.
Is there anyone here that used a BOV instead a DSV on an old vintage double hose reg?
Oh, by the way I'm now to the site.
Long time diver.
First dive 1977 in a pond .
Hi everyone.
Joe the Trucdiver

 

[runsongas]

feels kinda extra. you aren't at risk of hyperoxia/hypoxia/caustic cocktail flood with a DH like with CCR that the BOV really makes a meaningful safety difference over a DSV and then switching to a backup reg.

 

[Nemrod]

The DSV for a DH regulator (like the Kraken) is to allow closing the DSV to switch to an octopus/secondary (for whatever reason needed), to allow removal of the mouthpiece underwater to shoot a bag, to allow surface loitering without constant free flow with each passing wave or if relaxing floating on your back, to make doffing gear easier and probably a few other things I cannot think of now. But none of them involve installing BOV for a secondary air source. Put your pony on it for solo? I do not think this a good idea.

Me with VDH Kraken and VDH Kraken DSV:

 

[happy-diver]

To think I was just talking to Bryan when I bought one of those things a couple of years ago
Paid him some compliments regarding all the work involved in dealing with us nincompoops

He was chuffed

 

[Scott G. Bonser]

The Trieste II has been upgraded with a larger can and diafram from the Scuba museum. I have large bore Dräger hoses and DSV on it.
It breaths really good.
Had to 3D print a couple hose adapters for the horns. To be able to use the dräger loop.
Come out good.
Is there anyone here that used a BOV instead a DSV on an old vintage double hose reg?
Oh, by the way I'm now to the site.
Long time diver.
First dive 1977 in a pond .
Hi everyone.
Joe the Trucdiver

Trucdiver, that was a good upgrade from TSM, however, I was told Trieste & Trieste II are notoriously difficult ‘breathers’ ???( …not sure why. I never had a problem with my Trieste II. ) ..Trieste was the FIRST SCUBA regulator I ever tried back in ‘74 that kindled the ‘fire’ to get me to get certified. Stephanie at Tarpoon Dive Center in Hialeah, FL has an easier suggestion that I have tried and it works. When you ‘mount’ your Trieste or Trieste II on the tank to dive, tilt it slightly so that the ‘supply’ line ( right hose ) is closer to the tank valve orifice. A trick she learned & I had to give it a try. …might work for you. My Trieste II has gauge and can take an octopus and power inflator for an O / W ‘diver’ but check intermediate pressure w/intermediate pressure gauge on your repair bench to compare and set to factory settings If you do that. Other things may come into play As well. Something I learned from Luis H. He is a fantastic and most knowledgeable individual in these matters.

…best of luck…
Scott G. Bonser
the ‘giantfroginthepool ’

 

[John C. Ratliff]

I have owned my Trieste II since the late 1970s. I have analyzed it a lot over the years, and it has undergone several revisions. The original Trieste II, out of the box new, had three major design flaws that made it harder to breathe than it should have been.

1. The main LP diaphragm was molded of neoprene, with a permanent “set” which had to be overcome to crack the valve. That “set” amounted to an addition of about 1.5 inches to the inhalation/breaking effort.

2. The main nozzle was not designed correctly. It had two large holes, one of which was pointed down the intake hose, and one of which was pointed into the case. It also had two auxiliary holes on each side of the nozzle, again allowing air into the case. This made for a very weak Venturi, which was mostly ineffective.

3. The set screw which positioned the nozzle left a lot of “slop” so that the nozzle wasn’t necessarily pointed directly down the intake hose.

I will detail how these were overcome in an addition to this post…okay, here goes:

The diaphragm

I home-made a new diaphragm for the Trieste II, out of rubberized nylon. It is like the original diaphragm for the MR-12 regulator second stage. I’ll let anyone who wants to in on the details if they PM me.

The Nozzle

A dive shop in Vancouver B.C. Took my Trieste II, removed the nozzle, and modified it. They completely filled in the back opening, and slightly enlarged one or the side openings. This mod made for a powerful Venturi, so powerful in fact that I needed to take a Healthways baffle plate out of the Healthways Scuba (gold label) and put it into the USD mouthpiece (glued it into the mouthpiece). This made inhalation really great.

Nozzle Orientation

I made that screw so that it hit the edge of the nozzle, and therefore the nozzle opening was oriented straight down the intake hose.

I dove my Trieste II regulator for decades with these modifications, having only one incident. That happened when that Healthways baffle plate came loose on a dive, and adhered to the intake mushroom valve, thereby completely closing off the inhalation. What did I do? Well, I was ascending from about 35 feet at Edmonds Underwater Park, where my buddy Bruce Higgins had put together an underwater park with sunken wrecks, lines for orientation, etc., when I could get on air out of my Trieste II. I simply switched to my MR-12 second stage octopus, and continued the swim in underwater. I replaced that mouthpiece several years ago with a DSV mouthpiece from VDH, and that solved the problem.

The home-made diaphragm has since been replace with a silicone diaphragm made by one of the members at VSS (the Vintage Scuba Community Forum). So now my Trieste II is the best-breathing regulator I own, followed a close second by the Mossback Mk 3 regulator (a modified DA Aquamaster, which has an entirely new first stage).

SeaRat

 

[Scott G. Bonser]

I have owned my Trieste II since the late 1970s. I have analyzed it a lot over the years, and it has undergone several revisions. The original Trieste II, out of the box new, had three major design flaws that made it harder to breathe than it should have been.

1. The main LP diaphragm was molded of neoprene, with a permanent “set” which had to be overcome to crack the valve. That “set” amounted to an addition of about 1.5 inches to the inhalation/breaking effort.

2. The main nozzle was not designed correctly. It had two large holes, one of which was pointed down the intake hose, and one of which was pointed into the case. It also had two auxiliary holes on each side of the nozzle, again allowing air into the case. This made for a very weak Venturi, which was mostly ineffective.

3. The set screw which positioned the nozzle left a lot of “slop” so that the nozzle wasn’t necessarily pointed directly down the intake hose.

I will detail how these were overcome in an addition to this post…okay, here goes:

The diaphragm

I home-made a new diaphragm for the Trieste II, out of rubberized nylon. It is like the original diaphragm for the MR-12 regulator second stage. I’ll let anyone who wants to in on the details if they PM me.

The Nozzle

A dive shop in Vancouver B.C. Took my Trieste II, removed the nozzle, and modified it. They completely filled in the back opening, and slightly enlarged one or the side openings. This mod made for a powerful Venturi, so powerful in fact that I needed to take a Healthways baffle plate out of the Healthways Scuba (gold label) and put it into the USD mouthpiece (glued it into the mouthpiece). This made inhalation really great.

Nozzle Orientation

I made that screw so that it hit the edge of the nozzle, and therefore the nozzle opening was oriented straight down the intake hose.

I dove my Trieste II regulator for decades with these modifications, having only one incident. That happened when that Healthways baffle plate came loose on a dive, and adhered to the intake mushroom valve, thereby completely closing off the inhalation. What did I do? Well, I was ascending from about 35 feet at Edmonds Underwater Park, where my buddy Bruce Higgins had put together an underwater park with sunken wrecks, lines for orientation, etc., when I could get on air out of my Trieste II. I simply switched to my MR-12 second stage octopus, and continued the swim in underwater. I replaced that mouthpiece several years ago with a DSV mouthpiece from VDH, and that solved the problem.

The home-made diaphragm has since been replace with a silicone diaphragm made by one of the members at VSS (the Vintage Scuba Community Forum). So now my Trieste II is the best-breathing regulator I own, followed a close second by the Mossback Mk 3 regulator (a modified DA Aquamaster, which has an entirely new first stage).

SeaRat

Hey there, John.
I had some of the the same modifications made to mine courtesy of VSS when Dan was still servicing these regs. Enlarging the orifice really helped quite a bit and it is one of my fave OW regs also w/rebuilt MR12 II octo and PI hose and SeaVue gauge. ( that’s been awhile ) . Another remedy to increase breathing efficiency from Stephanie K. of Tarpoon Skin Diving Center…. When mounting on your tank valve, slightly tilt ( within reason ) your ‘supply’ hose closer to the tank valve orifice. She says there is a big difference. I never got to try this as my Trieste II had already been modified by that time.

Scott G. Bonser

 

[Nemrod]

. When mounting on your tank valve, slightly tilt ( within reason ) your ‘supply’ hose closer to the tank valve orifice. She says there is a big difference. I never got to try this as my Trieste II had already been modified by that time.

Scott G. Bonser

I would probably not do that. Anything that moves the center of the diaphragm further from the diver's back is going to increase the distance from the center of the diaphragm to the center of the divers lungs thus increasing the WOI. And tilting the can so that the supply side horn is nearer is also moving the center of the diaphragm further from the lungs. So, yes, I am skeptical of this procedure.

The Trieste was cool looking but the tiny, stiff diaphragm coupled with an inefficnet Venturi (and fixed yoke) ruined what could have been a game changer for DH regulators. Yes, some have taken the body and teamed with a full size diaphragm or other modifications, some very successful, but IMO a Trieste is a nice collectable and that is about it, maybe large frogs in small ponds might get away with them on occasion but small fishes in very large oceans, might just get eaten by large fishes with teeth .



This is what you want, centered between the shoulder blades, diaphragm as close to the back as possible and square to the diver. I am sure Mr John could school a few folks on it .



This being from the Bible of SCUBA diving, handed down by God from a burning sea fan, there is nothing in the THE BOOK about tilting the regulator this way or that.

 

[John C. Ratliff]

Well, you can see that I like my double hose regulators low on the back, like Nemrod states:

Subtidal Clambed Survey006 by John Ratliff, on Flickr

Here’s where I like my double hose regulators on my twins. This one has a Scubapro valve, which can be “twisted” a but, but it is not necessary on a tank with a 6.5 inch diameter.

IMG_1761 by John Ratliff, on Flickr

But for my smaller twin sets, I do like to use the center part of the manifold turned just a bit.

John Photos003 by John Ratliff, on Flickr
With the smaller tanks, and especially with a military harness, tilting that center section a bit down allows the face of the double hose regulator to sit with the entire box against my back, rather than the bottom edge digging into the top of my back. That is the only drawback to the solid manifold, in that this tilt is no longer an option.

SeaRat

 

[Scott G. Bonser]

Well, you can see that I like my double hose regulators low on the back, like Nemrod states:

Subtidal Clambed Survey006 by John Ratliff, on Flickr

Here’s where I like my double hose regulators on my twins. This one has a Scubapro valve, which can be “twisted” a but, but it is not necessary on a tank with a 6.5 inch diameter.

IMG_1761 by John Ratliff, on Flickr

But for my smaller twin sets, I do like to use the center part of the manifold turned just a bit.

John Photos003 by John Ratliff, on Flickr
With the smaller tanks, and especially with a military harness, tilting that center section a bit down allows the face of the double hose regulator to sit with the entire box against my back, rather than the bottom edge digging into the top of my back. That is the only drawback to the solid manifold, in that this tilt is no longer an option.

SeaRat

Yes…that makes sense. Many times some ‘old timers’ have ‘old’ remedies that are just what they appear. I like the modifications to my Trieste II. It makes it a ‘performer‘ much like my Royal Aquamaster and Waterlung Dual-Air. My main critique to Ms. K is what about ‘twisting it‘ out of place? ( shouldn’t but could ) as once the yoke is attached to the tank valve it should stay put. …just looked a bit ‘dicey’ to me.
Thanks for your input and photos to boot!!!

my 1st try w/SCUBA in a neighbors pool didn’t seem to have a difficulty w/breathing but I wasn’t fighting a current either..