Different Shape SCUBA Tanks

[spectrum]

For the swimming velocity of a diver I'm not sure there is a whole lot to be gained by massaging the cylinder (would it still be called a cylinder?) profile.

There are so many opportunities within existing gear choices, configurations and techniques that the R&D would be hard to justify.

Still it's fun to dream.

Pete

 

[Gilldiver]

There are a few problems with any composite wrapped tanks:

1) All composite fabrics will wick water. Kevlar, Graphite, and one of the glasses (S or E, I just can't remember right now) wicks real well.

Once water is along the threads it lubricated them within the resin matrix and you start to lose a good % of your strength. At this point, you will be trashing the tanks. But finding out whan it happends is hard to do, so you will be working on a time/life function.

2) Graphite and Aluminum do not like each other. They form a Carbon/Aluminum galvanic couple and the aluminum is coroded under the fabric where it is very hard to detect.

So any composite wraped tanks will have a very short life for diving.

As for the titanium tanks from Russia, they were shown a few times at DEMA and other shows and had working pressures of 5,000 to 6,000 psi. But A) compressors that can do that are few and far between B) No one wanted to pay $1500 a tank and C) Titanium is very scratch sensitive and any deep scratches would trash the tank as they could not be blended out.

Pete

 

[shadragon]

There are a few problems with any composite wrapped tanks:

1) All composite fabrics will wick water. Kevlar, Graphite, and one of the glasses (S or E, I just can't remember right now) wicks real well.

So why not use an outer or mid layer of rubber or impermeable material to stop that?

Here is a dream. What about a transparent air bottle. Makes visuals a lot easier...

 

[ClayJar]

How long will this thread get before someone suggests the "suicide bomber" setup (with a bunch of bratwurst-size tanks strapped together and worn like a cummerbund or bandolier)?

(Okay, so the $321,000 for hydros would be a bit much, but nothing's perfect.)

 

[shadragon]

How long will this thread get before someone suggests the "suicide bomber" setup (with a bunch of bratwurst-size tanks strapped together and worn like a cummerbund or bandolier)?

(Okay, so the $321,000 for hydros would be a bit much, but nothing's perfect.)

Hydros... Wee down neeed no steenking hydros...

 

[wilkie]

As I recall US Divers tried to market a "really small" twin set that would fit into the standard BC tank band in the early 90's. Only saw 3, or 4 pair in dive shops, never saw any in the water though ( high price + low volume )

 

[Dustinh]

It has become huge in the paintball industry to use carbon fiber tanks. These tanks are very light, but have all kinds of issues, especially after they get wet. The European paintball league temporarily banned the use of carbon fiber tanks recetly, because they were leaking and cracking. Not what I want to trust with my life underwater.

Carbon fiber tanks must be hydro tested ever five years, but they only have a 15 year life span. After that, DOT mandates they be destroyed.

For now, I'll take aluminum and steel.

 

[John C. Ratliff]

He used tripple 30's that had a three part US Divers manifold in the yellow fiberglass back pack. The manifold was a total PITA to assemble and get all the connections not to leak as they were brass on brass compression fittings. Much like the Sherwood manifolds on many old twin 72's sets. You had to get a "Big" wrench to tighten the caps down.

The yellow backpack was developed to be better looking for his films.

The MK 15 rebreather uses a sphear for O2 and dilutant. It is one of the problems with getting a MK15 or MK15.5, the sphears are almost imposable to replace.

Actually, the UDS-1 is a set of triple 35 cubic foot tanks, for a total of 105 ft3. They are AL 3000 psi cylinders, with a much larger, one-inch diameter cylinder opening. The valve is made of aluminum, to be compatible with the cylinders. The valve has huge openings into the cylinder:

The problems with servicing this unit has to do with mating the cylinders to the shell, and it typically takes me about an hour to do mine (but I'm getting better at it).

In the water, once you know how to balance the unit and how to modify the harness, it is a dream. It needs about 6 pounds of weight on the top of the unit, or it will float away from the diver's back and become a real drag in the water. The harness is a cross between the European system, which uses no waist strap, and the American system, which has a waist strap. Because of this, the waist strap is way too low to work, and should be removed. The unit comes with a crotch strap and a European-style buckle which has a notch for the retainer on the crotch strap. This buckle should be put onto your weight belt, and then use only the crotch strap (no waist strap) for the unit.

There were some engineering problems, particularly with the filler hose and the valve in it which allowed for filling. I have overcome these too.

Once this is done, the unit works extremely well in the water. Because of the huge openings, it can be breathed to "zero" indicated psi on the SPG, and no resistance will be felt. You will finally feel resistance with about five breaths left in the unit. It has a J-reserve and a SPG, so no one should run out of air.

I was in the Clackamas River today with my UDS-1, and really enjoyed using it, especially in the current. It rides well, and is very streamlined.

SeaRat

 

[Thalassamania]

There were some experiments done both for emergency breathing supplies and main tanks using long lengths of high pressure tubing that was wound about itself and, at least in theory, could have been finalized in just about any shape. The ones I saw were basically scuba tank shaped and could hold 10,000 psi (which was not a practical fill, then or now), but it was a piece of military foolishness.