NED HydroTwin II

[vance]

I just finished rebuilding another New England Divers rebranded HydroTwin II. It's no beauty, but I'll feel fine about using this one.



I am starting a new thread on this one, since the other NED thread is 12 pages long. The main reason I'm posting this is to show the different style HP seat, soft seat, and pin this one has (had).

I have had a few of these apart, including a DualAir, and they've all had the plastic Healthways style soft seat and concave hard seat. This one has a brass flat- and square-bottomed soft seat and a hard seat with a volcano orifice like a USD reg.



This soft seat is shot. I tried polishing it, but the soft seat is badly grooved and chipped. I have a bunch of the OTHER kind of spares (which is a large part of why I got this one, only to find it has different parts in it). They do look similar to the later single hose Sportsways HP parts, but they aren't identical. They might be interchangeable, but I didn't try.  

The first stage body is outwardly the same as the other NED I have, and I couldn't think of any reason why I couldn't replace the whole setup with the parts I had, so I did. I had to make a new HP pin for it. BTW, the Healthways single stage hard seats are the same diameter, but have a smaller orifice, I found. So you have to be careful about that,  but I had a couple NOS hard seats that have the correct orifice.

The original HP diaphragm assembly would not seat correctly with the new parts, although the assembly appears to be the same as my other regulator's assembly. But again, I happened to have NOS parts. After some drama with the second stage and fooling around with IP adjustments, it holds a solid IP of 140. I think these regs like a higher IP setting, but this'll do for now.

As for the rest of it, the cans had to be flattened, some dents massaged out, and the usual rubber parts needed replacing but it's in pretty decent shape but for some minor cosmetic issues. Unfortunately, the label is a bit brutalized. The main diaphragm is excellent. It did come with a hoseloop, but the hoses are stiff and not trustworthy. I wouldn't dive them anyway, since these regs benefit from using a larger diameter loop.


   

[SeaRat]

I haven't had my Hydro-Twin II apart for ages, and I'm not sure whether it has the same parts or not. I suspect it does. The interesting thing about my Hydro-Twin is that it's labeled a Hydro-Twin, but it is a balanced first stage. So I'm thinking that it was one of the first Hydro-Twin II regulators.

IMG_2645 by John Ratliff, on Flickr

John

[SeaRat]

I was just looking through my older publications, and found this article in The Journal of Diving History, Volume 221, Issue 4, Fall 2013, Number 77. The article is titled, under "Vintace Scuba," "Sportsways, A Collector's Review, by Ed LaRochelle. In it he states,

WATERLUNG HYDRO-TWIN
manufactured 1963

The fgirst stage for the hydro-Twin (see photo of 1st stages) was the same as that of the Dual Air, with the exception of the safety pressure relief valve that was no longer needed. The second-stage portion of the reruulator used a down-stream assembly rather than the up-stram tilt valve, therefore eliminating the need for the reflef valveThat low-pressure port now came with a removable plug, making it available for other low-pressure service uses. The case, exhaust valve, cover and clamp were the same as the first model Dual Air. The hoses, mouthpienec and clamps were also unchanged. The label was metal foil glued to the cover, but this time the color was dark blue and stated WATERLUNG HYDRO-TWIN. Serial numbers began with H (for Hydro) and to date I have been able to verify numbers from H-00052 to H-00495. This equates to only 443 confirmed with a probable amount of less than 1,000 actually manufactured. This number is very low in part because halfway through the year Sportsways was already making plans to replace the first stage. There is an advertisement in the May 1963 issue of Skin Diver Magazine promoting the new Hydro-Twin II.

WATERLUNG HYDRO-TWIN II
manufactured 1964 to 1968

In 1962 Spratsways introduced their newly designed balanced first stage for the "Master Diver" single hose regulator. (see photo of 1st stages and diagram of 1st stage)

A balanced unit is when the high pressure seat assembly operates in a space that is equal pressure on both ends of the assembly allowing it to move smoothly back and forth at any tank pressure. They also eliminated on of the law pressure ports. During 1963 Sprotsways was already beginning to incorporate that first stage into the two-hose regulator 9see photo Skin Diver Magazine advertisement 1963) renaming it HYDRO-TWIN II..

...The label, however, was now orange and black, and was printed on a vinyl type material and glued to the case cover. Serial numbers begin with the letter B for (balanced) and to date I have been able to confirm serial numbers from B-02549 to B-03076. This equates to 527 confirmed, with a probable amount of less than 3,000 actually manufactured during the four year period...

IMG_2647 by John Ratliff, on Flickr
Well, this is me, using my Hydro-Twin with the blue label. The only thing is that this regulator is at serial number H-00553, and it is a balanced design. So I have lengthened slightly the confirmed number of Hydro-Twins made, but also have a regulator that is in that transition from the unbalanced first stage to the balanced first stage, without a label change!

John

PS, yes, those are Voit hoses and mouthpiece, and I did not like the original Sportsways mouthpiece (which I still have), and the hoses were rotted out. And, in this configuration, it breathes really nicely.

[SeaRat]

I just found the photo which is the breakdown of parts for my Hydro-Twin regulator. The HP seat is very hard to see (white on white background), but it shows the balanced nature of this regulator, which is not supposed to be balanced.

IMG_2592 by John Ratliff, on Flickr

Here's a better show of the parts:
IMG_2591 by John Ratliff, on Flickr

John