I can't argue with that, however little sense it makes in the real world
Chris
Chris
Oms Vs Faber
- Thread starter RUFUST
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Arnaud
Contributor
Ben is right. That's the only difference.
Lubold, I thought they had stopped the painting thing...
Lubold, I thought they had stopped the painting thing...
Arnaud:
I assume you are talking about the galvanized OMS (faber) cylinders???
AFAIK, they are still not available. The OMS and Faber cylinders are sprayed with a galvanizing coating, and then painted. The PST's are hot dipped galvanized, which produces a much thicker coating. OMS wanted to produce the same type of results, but I dont think they have been able to get satisfactory results as of yet. From what I have heard, I would not be surprised if they have scrapped the whole idea...
I heard the backup also had to do with lawyers, I agree though, since they aren't out now they probably won't be.
Ben
Ben
CRDiver
Contributor
LUBOLD8431,
If what I wrote was "untrue," why (according to published data) is my Faber 45 is -2.4lbs. full and +0.8lbs. empty, while the OMS 46 is -4lbs. full and neutral empty? In your example, a Faber 108 is -4.4 full and +3.4 empty, while an OMS 112 is -8lbs. full and -1lbs. empty. Bob is probably right that the numbers are figured differently under different conditions, but there's still quite a disparity, particularly between the 108/112.
The only thing I wrote which was "untrue" was in regards to Fabers being more negatively buoyant than the OMS. But there's still a significant difference.
If what I wrote was "untrue," why (according to published data) is my Faber 45 is -2.4lbs. full and +0.8lbs. empty, while the OMS 46 is -4lbs. full and neutral empty? In your example, a Faber 108 is -4.4 full and +3.4 empty, while an OMS 112 is -8lbs. full and -1lbs. empty. Bob is probably right that the numbers are figured differently under different conditions, but there's still quite a disparity, particularly between the 108/112.
The only thing I wrote which was "untrue" was in regards to Fabers being more negatively buoyant than the OMS. But there's still a significant difference.
Chris,
I don't think Chuck was aiming at you, Ben has explained how OMS comes up with a higher volume, the cylinders are manufactured at the same plant and if you put them side by side they would be identical other than the paint.
Chris
I don't think Chuck was aiming at you, Ben has explained how OMS comes up with a higher volume, the cylinders are manufactured at the same plant and if you put them side by side they would be identical other than the paint.
Chris
CRDiver:
for buoyancy specs usually Faber publishes the numbers WITHOUT valves and OMS publishes their specs WITH valves.
ALso the numbers can be made to show whatever the manufacturer wants to say... The weight when full varies depending on what gas you put in it.. if I put in heliox 80 (80% helium) the tank when full weights considerably less than the same tank filled with Air
I also have purcahsed numerous 3l (20 cuft) steels from both OMS and through Faber suppliers the only difference is the Stamping on the cylinders and that Faber cylinders are White while the OMS 3l are blue.
for reference look at OMS and faber specs for the "C45 (46)" for BOTH the weight is 17.6 lbs, have a length of 23 inches and a diameter of 5.5 inches.. since they DISPLACE the same amount of water AND the weight is the same (out of water), are made of the same material, Have the same liquid capacity (7 LITERS) they MUST have the same buoyancy characteristics in the water..
I wish US americans would stop specifying cylinders in Cu ft and just use liquid capacity.. It makes so much more sense for gas planning and available volume.
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Check out the fine print under OMS and Faber in the following charts ...
http://members.aol.com/jsuw3/tankspecs.html
As an additional exercise, conduct a search for scuba cylinder specifications and note the discrepency in the same cylinder on various charts.
These are used for comparison purposes only ... not as absolute values.
It's interesting to note that many do not spec the buoyancy characteristics of their cylinders with valves attached ... after all, you can't dive it that way.
... Bob
http://members.aol.com/jsuw3/tankspecs.html
As an additional exercise, conduct a search for scuba cylinder specifications and note the discrepency in the same cylinder on various charts.
These are used for comparison purposes only ... not as absolute values.
It's interesting to note that many do not spec the buoyancy characteristics of their cylinders with valves attached ... after all, you can't dive it that way.
... Bob
CRDiver
Contributor
I can see where figuring buoyancy without the valve would produce different numbers, but the difference between the 108/112 seems too great to just be valve weight: +3.4 versus -1 when empty.
CRDiver:
I can tell you that OMS has some mistakes on their web site.. the 98, 45 and 20 weights are the weights without valves(contrary to what they state).. I have checked these in the past, but their buoyancy numbers seem to be pretty close
My guess is that they added the valve weight (their standard valves are very heavy) onto the buoyancy characteristics but not onto the empty weight..
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