Triple 44's?

[Nemrod]

In those times and correct me Captain and others if I am wrong--but--doubles and triples were not primarily for increased capacity but also for balance and trim and positioning of the double hose regulator low on the back. The short double and triple tanks allow the tanks to be worn correctly low for best positioning of the double hose regulator without compromising capacity. An aluminum 80 or such as that worn low enough to correctly position the regulator leaves the tank hanging down on your rear end unless you are fairly tall. The short doubles and triples did not have that problem.
I am building a set of triple 30s. These will be Catalina aluminum 30s. At 3,000 psi I will have 90 cf but at the reduced 2475 psi working pressure of the triple manifold it will result in something less. BUT the balance should be excellent. I might go with 40s but I prefer to keep it light enough to be able to easily lift. N

 

[ItsBruce]

Lloyd used tripple 35s at least once. My friend has them. They hydroed in and haven't been used since.

 

[captain]

Nemrod, you let the cat out of the bag.

 

[John C. Ratliff]

The old US Divers triple tank systems were triple 44s, depending upon the source. Rick and Barbara Carriers book, dive, the complete book of skin diving, Wilfred Funk, Inc., 1957, page 276, has the "Equipment listings" that were current as of May 1956. They include this entry:

Stock Number, Description, Prices
B3, Navy triple-tank unit (D1 + 3H3 + J3 + L3 + W3) 132 cu. ft., $295.00

Fred Roberts, in his book Basic Scuba, Second Edition, D. Van Nostrand Company, New Jersey, 1963, states in Table 3-31 about air in remaining after reerve action in single, twin and triple cylinder blocks, "J" type reserve, that the triple blocks used were either 132 (3-44's), 150 (3-50's) or 213.6 (3-70+'s) cubic feet. He also notes that "Triple installation not available in 1963," so all the triples that are vintage were not being made after that date, except for a Nemrod model which came later.

Concerning the UDS-1 system, I have one. After I worked out the "bugs" it is a great system to dive. But attention must be paid to details. I put together an extensive thread on it in the Vintage Diving website below:

http://vintagescuba.proboards2.com/index.cgi?board=general&action=display&thread=1095723435&page=1

This is one of the greatest breathing scubas ever developed, but it also had three real, important design defects which kept it from becoming popular. The dive shops hated it, as it takes well over an hour to break it down, and putting it back together takes the same amount of time (and this is when you are familiar with it). But once you get the buoyance problems corrected (weight must be added to the top of the unit), it is wonderful in the water. The other major design defect is the harness system, which if used as designed won't fit the normal diver. It is designed NOT to be used with a waist strap (European system which is designed for the weight belt to be the waist strap), but one is provided.

Concerning the breathing qualities of the UDS-1, take a look at that thread, and the valve. It has the largest openings ever designed into a scuba system. I can breath it down to zero psi on the guage, and not feel any restrictions. When you feel a restriction, you have about 5 breaths left.

There is a J-valve designed into the system, which is the best-designed J-valve ever put on a system. The literature with the system says the reserve is set at 1000 psi on the one cylinder, but I think it is actually a bit higher, as it equilizes out on mine at about 400 psi in all cylinders after activation. You cannot accidentally trip the J-valve, as it is recessed into the case, and it is in an on-position when it is down (hitting it would put in down, so it stays on).

SeaRat

 

[John C. Ratliff]

Ooppss!! It looks like they pulled the UDS-1 from the bidding on E-Bay.

SeaRat

 

[pescador775]

I used triples for many years, the US Divers version and later, my homemade set based on the UDS 35 aluminum and Nemrod manifold. The Nemrod will easily handle 3000 psi but a special O ring is needed for the face. This matches the Poseidon O ring normally found in the repair kit for the original "side breather" regulator.

The USN used triples in the late 40's-early 50's. Basically, they ordered whatever Cousteau was using. Later, they discovered that the double 70's (+ rated 64) held more air and breathed better. The positioning of the USD double manifold allowed the reg to sit lower and had better hydrostatic balance in some diver positions. The reg would not whack the back of the diver's head. The triples do almost as well for different reasons, eg because of the thin tanks that are used. When swimming horizontally, the regulator rides flat against the back, not elevated. Also, the short 44's (+ rated 40) can be adjusted somewhat lower. In those days, divers were, on average, shorter and thinner than today, and so were the tanks.

Regardless of the physics of these tank/regulator combinations, the balance can be upset by the use of backpacks. This is not a problem with the triples if a compact pack is used but doubles should only be used with the Navy type harness. Otherwise, the tanks and regulator can be offset too far from the diver's back.

 

[Nemrod]

""Also, the short 44's (+ rated 40) can be adjusted somewhat lower. In those days, divers were, on average, shorter and thinner than today, and so were the tanks.

Regardless of the physics of these tank/regulator combinations, the balance can be upset by the use of backpacks. This is not a problem with the triples if a compact pack is used but doubles should only be used with the Navy type harness. Otherwise, the tanks and regulator can be offset too far from the diver's back.""

Actually the modern back plate (BP) such as Hammerhead makes and commonly used with a wing type BC holds the double tanks as close to the back as the harness, maybe 1/8 inch difference. These can be had in stainless, aluminum and ABS type plastics and in some "reduced" weight versions that are essentially skelontonized.

Please Pescador, whixh Nemrod manifold are you using and could you elaborate on the o-rings etc? Where did you find the 35cf tanks?

Yeah, I know what you mean about people once being smaller than now, people are just huge compared to the 60s and 70s. Mostly bigger around and much heavier but perhaps a bit taller on average as well. I am not sure the cause but I suspect along with it we will begin to see a reduction in average lifespan for the first time in the last few hundred years. Big does not mean healthy or more important--durable. N

 

[pescador775]

Thanks. The 35's are from the old UDS-1. A custom made bushing is needed to convert 1" NPTS to 1/2"NPT.

The Nemrods show up on EBay from time to time. I saw a new manifold a couple months ago. The arms are very long, for triple 72's. Each has to be shortened by 1 1/2".

The face O ring looks like a regular fat O ring as used on valves made prior to 1975. However, it is actually metric. Only the Poseidon O ring is reliable at 3000 psi.

The interior surfaces of the Nemrod valve are rather rough. When old rubber builds up deposits inside, a new ring (in the arm groove) will not seal reliably inside the center post. Small leaks can occur. I cut the arms just long enough so that they must be screwed all the way in to the center post. Thus, I can insert an additional O ring by sliding onto the small radius of the arm. When the arm screws into the center post the additional O ring is compressed against the interior shoulder of the post. Fool proof, no leaks.

 

[pescador775]

Rant: One of the several good design features of vintage equipment is the sensible, small air passages found in the valves and regulators. This started to change about 1970 when Scubapro designed, advertised and sold a "flow through" piston regulator which had a rather large bore in the stem. They bragged that the large flows made breathing easier. This was a false claim and was potentially dangerous in concept. Mostly, it made dying easier. However, it didn't worry me much at the time because the tank valve passages remained much smaller than the piston stem which cancelled out the danger. The danger is related to out of air situations which can develop through carelessness (me) or malfunction (everybody else). In the "old days" this problem was never a killer because the small air passages alerted the diver to a breathing restriction. As the diver ascended, the pressure differentials released more air to the diver, plenty enough to surface without choking. Nowadays, there are several brands of valves which are onto the same advertising path as Scubapro, large passages, "easy breathing". When used with a modern, "low restriction" regulator the diver who accidentally finds that he is out of air, is also out of luck.

 

[Nemrod]

If you want a small passage you can insert an orifice inside a hose adpater for single hose. My Royal AquaMaster and several single hose regs I have including my Voit MR12 and Teknas will empty a tank completely, you only find your out of air on the last breath. My Mistral will do that also, the less air in the tank the easier it breaths right down to hte last drop, only right at the end do you notice it is not producing enough air. Darn that when that happens.

How did you cut the Nemrod manifold cross tubes? I have a Nemrod valve in wonderful condition but it does seem awfully wide.
N