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Post by ltstanfo on Jul 2, 2007 5:03:12 GMT -8
SeaRat, Since we both have UDS-1 rigs I though you might find this "interesting". cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=230147261785&ssPageName=STRK:MEWA:IT&ih=013By the way, this is the same seller who previously tried to sell this same rig for $2000 and got no takers. I offerred her $100 for a quality copy of the owners manual (see photos on auction site) but she was apparently not interested. I guess someone really wants a UDS-1. :-) Regards, Ltstanfo |
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Post by scubadiverbob on Jul 2, 2007 10:47:22 GMT -8
WOW! Aren't these just plastic covers that go around the tanks? They look cool.
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Post by ltstanfo on Jul 2, 2007 16:25:12 GMT -8
WOW! Aren't these just plastic covers that go around the tanks? They look cool. They are much more than that. I'll let SeaRat tell you his opinion but I think the UDS-1 was a very interesting "might have been". There are three tanks (35cuft each) attached to a triple manifold that has a built in first stage regulator. To top it all off, the tanks, manifold and retaining hardware are all aluminum. Yes, the yellow shell covers it all for a very nice "cousteau effect" but once you dive with one, you get an idea of what might have been and just how neat the gear really is. Regards, Ltstanfo |
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Post by SeaRat on Jul 2, 2007 19:43:50 GMT -8
Yes, I looked at it as it came up, but when it went high, I said "Forget it." I have mine, and I really enjoy it a lot in the water. The UDS-1, once properly balanced and understood (the harness is a bit challenging if you don't understand the European harness system without a waist strap), it handles very nicely in the water. I've had it in high current situations in rivers, and love the way it is balanced, hugs my back (with weighting on the top of the unit), and presents a very low profile to the water. If USD had taken just a few more measures to ensure its success, it would have been really nice. Attention to detail, this is what it's all about, and unfortunately, USD did not do this with the UDS-1. But with just a few little modifications, it is really nice.
John
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Post by scubadiverbob on Jul 2, 2007 20:28:32 GMT -8
I never dove with one. When I first saw it, I thought it worked like a Dacor Nautilus CVS. I can see an advantge in thick kelp. I've had kelp get tangled around my tank and regulator on the surface. So, does the small triple tanks make it more comfortable on the back? I have lower back problems (S1-L5); Nuerosurgeon said I can still dive. Might be something worth checking out. I don't have that much money to spare right now.
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Post by ltstanfo on Jul 3, 2007 5:21:33 GMT -8
ISo, does the small triple tanks make it more comfortable on the back? I have lower back problems (S1-L5); Nuerosurgeon said I can still dive. Might be something worth checking out. I don't have that much money to spare right now. The weights are similar to traditional configurations. The difference is in the balance (in / out of water) and it usefullness in current (something that SeaRat covered well). I love diving with my UDS-1! It really is a neat piece of equipment that not only dives well but gets lots of interesting looks and comments from other divers. ;D As for cost... obviously one man's trash is another man's treasure but unless the UDS-1 is made of gold or platinum, it simply isn't worth $1000. I paid $350 for mine and spent another $150 in rebuild (1st and 2nd stage, hydro and vis for tanks). I'm sure prices vary around the country (and by seller) but $1000 is nothing but pure profit (for the seller). Regards, Ltstanfo |
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Post by JES on Jul 3, 2007 14:38:02 GMT -8
Are the tanks on the UDS-1 made out of 6351 alloy? The age of these systems would suggest that they are. If so, the UDS-1 would be an expensive wall hangar since many LDS's (read probably every LDS in Florida) won't fill tanks made of 6351 alloy.  |
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dbg40
Senior Diver
Posts: 66
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Post by dbg40 on Jul 3, 2007 15:16:06 GMT -8
Don't know if it's still there, but a fiew weeks ago I found one on a gear site for 500$.
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dbg40
Senior Diver
Posts: 66
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Post by dbg40 on Jul 3, 2007 15:20:57 GMT -8
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Post by SeaRat on Jul 3, 2007 17:03:35 GMT -8
Are the tanks on the UDS-1 made out of 6351 alloy? The age of these systems would suggest that they are. If so, the UDS-1 would be an expensive wall hangar since many LDS's (read probably every LDS in Florida) won't fill tanks made of 6351 alloy. The specifications for the UDS-1 (I have a copy) show that the tanks are made of "6351-T6 aluminum alloy: D.O.T. Permit No. 6498." The manifold is made of "Forged 6061-T6 aluminum, hard anodized." My tanks have gone through two hydros, and the LDS will fill them. These tanks have a larger opening than standard diving cylinders (1 inch rather than 3/4 inch), which I've been told (ScubaBoard) will give them more strength and less likelihood of cracking (larger diameter leads to a longer thread which means the force is distributed over a longer/bigger area so there's less stress per area of the thread). This large, one-inch opening allows extremely large (in comparison to other scuba manifolds) openings in the aluminum alloy manifold, coming off three cylinders, which gives it an extremely large amount of air available to the regulator. You can breathe this unit down to "zero" SPG indicated pressure without feeling any restriction in breathing. You have about three breaths left when you feel the restriction in breathing resistance. This is why they are so good in high current (rivers), as if you work hard, it will provide all the air you need. The J-reserve valve is set on one cylinder at about 900 psig, and cannot be easily tripped by bumping into things underwater, as it is pointed down in the "On" position (mine, I think, is a bit higher, as when it tripps it leaves me with about 450 psi in all cylinders). You manually reach around and trip it with your left hand (it's within easy reach). By the way, I have some other AL 50 ft3 tanks that are also of the 6351 alloy, and the LDS simply has a device which tests for cracking during their visual inspections. There are some shops in the Seattle area which will not fill any style of AL tank, so that fear is out there. John |
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Post by SeaRat on Jul 3, 2007 17:05:19 GMT -8
So Discount Diver's Supply has another UDS-1 available. I got mine from them for $550 over five years ago. John |
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Post by ltstanfo on Jul 3, 2007 19:19:09 GMT -8
So Discount Diver's Supply has another UDS-1 available. I got mine from them for $550 over five years ago. John Nope, the link is out of date. I called them (Discount Divers) about three months ago when I discovered their UDS-1 (pointed out by someone here on VSS) and was told that the unit was no longer for sale. I don't know if it is sold or they are keeping it for themselves. Regards, Ltstanfo |
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Post by ltstanfo on Jul 3, 2007 19:25:47 GMT -8
Are the tanks on the UDS-1 made out of 6351 alloy? The age of these systems would suggest that they are. If so, the UDS-1 would be an expensive wall hangar since many LDS's (read probably every LDS in Florida) won't fill tanks made of 6351 alloy. Yes, the system is 6351 but the hype / fear over that alloy is quite exaggerated (IMO). My local hydro facility did the hydro late last year without complaint. I inquired about the alloy and they said they had never seen one fail. My local dive shop (here in Huntsville, AL) did the visual and has no issues filling it. I am aware that some shops will not fill Aluminum tanks older than 5 years and I think it is silly. If the tank has a recent hydro and a current vis their refusal (to me) is uncalled for... but it is their shop. The quarry that I dive in (Blue Water Park in Birmingham) will fill it without issue although I insist on watching them do it since I am still using the original fill system and insist on a slow fill (this was perhaps the only real design flaw of the UDS-1...I hope mine keeps working so I don't have to jury rig a replacement). Regards, Ltstanfo |
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Post by luis on Jul 3, 2007 20:04:38 GMT -8
The specifications for the UDS-1 (I have a copy) show that the tanks are made of "6351-T6 aluminum alloy: D.O.T. Permit No. 6498." The manifold is made of "Forged 6061-T6 aluminum, hard anodized." My tanks have gone through two hydros, and the LDS will fill them. These tanks have a larger opening than standard diving cylinders (1 inch rather than 3/4 inch), which I've been told (ScubaBoard) will give them more strength and less likelihood of cracking (larger diameter leads to a longer thread which means the force is distributed over a longer/bigger area so there's less stress per area of the thread). John Hi John I don't know who offered that information, but I am sorry to tell you that it doesn't make any sense to me. Hoop stresses on any cylindrical section of a pressure vessel are directly proportional to the diameter ( and inversely proportional to the thickness at that section). Sustain Load Cracking is caused by hoop stresses not the load on the thread from the valve. The cracks are perpendicular to the threads. My understanding is that they start on the neck due to the forming process of the neck. The only positive theory that I can offer is that maybe since the cylinder is relatively small and the neck big, maybe the forming process did not leave as many imperfections. But, that is pure speculations. The good news is that a very careful visual inspection of the threads should be a bit easier since the neck is bigger. The other real bad news is that that eddy current test equipment is most likely not available for that size neck. SLC catastrophic structural failures are extremely rare. Considering the number of tanks that were made from AL6351, the number of tanks with cracks is relatively small, but early detection of cracks is occurring on fairly regular basis. I have seen several confirmed large cracks just from the few LDS in my area. The wall thickness on an aluminum tank is so thick that a tank with a crack will pass hydro test without a problem. Only when the crack is large enough will the tank leak or catastrophically fail. It is not uncommon for a crack to break through enough for the tank to leak, but the tank still hold pressure (at least temporarily). IMO very scary situation. There is at present a thread in the New England section of ScaryBoard discussing the recent failure of an AL6351 tank in Rhode Island. IMO with proper testing and inspection these tanks should still have some useful life, but I just feel more comfortable with steel tanks. |
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Post by luis on Jul 3, 2007 20:26:48 GMT -8
Are the tanks on the UDS-1 made out of 6351 alloy? The age of these systems would suggest that they are. If so, the UDS-1 would be an expensive wall hangar since many LDS's (read probably every LDS in Florida) won't fill tanks made of 6351 alloy. Yes, the system is 6351 but the hype / fear over that alloy is quite exaggerated (IMO). My local hydro facility did the hydro late last year without complaint. I inquired about the alloy and they said they had never seen one fail. My local dive shop (here in Huntsville, AL) did the visual and has no issues filling it. I am aware that some shops will not fill Aluminum tanks older than 5 years and I think it is silly. If the tank has a recent hydro and a current vis their refusal (to me) is uncalled for... but it is their shop. The quarry that I dive in (Blue Water Park in Birmingham) will fill it without issue although I insist on watching them do it since I am still using the original fill system and insist on a slow fill (this was perhaps the only real design flaw of the UDS-1...I hope mine keeps working so I don't have to jury rig a replacement). Regards, Ltstanfo As I mentioned, Al 6351 tanks will pass hydro testing with confirmed cracks on the neck. As a mater of fact, the best time to check for cracks seems to be just after a hydro. Logically the hydro tends to open the crack. A good visual with a highly magnifying mirror can catch most of the cracks. Now for the real bad news. I forgot about it on my last post. There is a new requirement from the DOT. I have seen the ruling and will try to get a copy and post it. The new requirement is that at time of hydro all AL6351 tanks are required to have a Visual Eddy (eddy current testing) performed and the tanks are required to be stamped "VE" next to the hydro test date. The reason this could be very bad news is because I am fairly certain that not eddy current probes have being made for that size neck (I will double check about this, I am a certified inspector). A custom made one would be prohibitively expensive. If you would like confirmation of the above statements you can call PSI and talk to the manager, Mark Gresham and he can refer you the the new regulations and codes. If you have your own compressor (or a dive shop operator that is either ignorant or looks the other way) you don't have to worry about codes and regulations, but I would still do very careful neck inspections with a highly magnified mirror. |
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