13 cubic foot bottle

[Scared Silly]

I looked at some on ebay. This one was cheaper when I asked him what size it was...
U S Divers Aqua Lung Aluminum Scuba Tank Professional
His reply was "Standard Size." :silly: Now it's higher than I would pay for a used tank anyway, presuming it's an 80 maybe, without hydro or viz info.

You would not want it anyways - it is an old Luxfer S80 made in the 80s (i.e. AL6357)

 

[DandyDon]

You would not want it anyways - it is an old Luxfer S80 made in the 80s (i.e. AL6357)

I need to learn how to read those codes.

 

[Blackwood]

Assume SAC = 1.0 if you're bailing out
Assume 1 minute at 130 feet to work out problems
Assume ascent rate 30 feet/min with average depth halfway between
Assume 1 minute stop at 50 feet, as you stated
Assume 1 minute stop at 30 feet, as you stated
Assume 3 minute stop at 20 feet, as you stated

TOTAL REQUIRED GAS:
1 min x 130 feet (4.9 ATA) x 1.0 cu.ft./min = 4.9 cubic feet
1 min ascent x 115 feet (4.45 ATA) x 1.0 cu.ft./min = 4.5 cubic feet
1 min ascent x 85 feet (3.55 ATA) x 1.0 cu.ft./min = 3.6 cubic feet
1 min ascent x 60 feet (2.8 ATA) x 1.0 cu.ft./min = 2.8 cubic feet
1 min at 50 feet x 50 feet (2.5 ATA) x 1.0 cu.ft./min = 2.5 cubic feet
1 min ascent x 40 feet (2.2 ATA) x 1.0 cu.ft./min = 2.2 cubic feet
1 min at 30 feet x 30 feet (1.9 ATA) x 1.0 cu.ft./min = 1.9 cubic feet
1 min ascent x 15 feet (1.45 ATA) x 1.0 cu.ft./min = 1.5 cubic feet

TOTAL REQUIRED = 24 cubic feet to get you back on the boat with 0 p.s.i. remaining

Holy extra steps, batman!

There's no reason to compute 130 to 60, 60 to 40, 40 to 30, etc..

130/2 feet average for 130/30 minutes plus the specified stops.

 

[ScubaInChicago]

Maybe the OP should learn how to calculate his own Rock Bottoms before making the jump to an appropriate sized pony.....

 

[DandyDon]

Maybe the OP should learn how to calculate his own Rock Bottoms before making the jump to an appropriate sized pony.....

Well, sure - we could shut down Scubaboard, too.

But then most of the divers you do see at 130 ft overall won't have a pony. I think it's wise to dive one myself, and I am glad to see the discussion.

 

[ScubaInChicago]

Well, sure - we could shut down Scubaboard, too.

But then most of the divers you do see at 130 ft overall won't have a pony. I think it's wise to dive one myself, and I am glad to see the discussion.

I think learning a RB gas plan is a good lesson to learn by researching and not by trial and error based on opinion......

...and if scubaboard were closed down who would we harass online???

 

[TSandM]

Well, the only way I'm going to be out of gas at 130 feet is an equipment failure. If I go head-down to look at something and my gas cuts off, I'm going to be stressed . . . briefly. If I have a redundant gas supply on my person, I'm going to deploy it, knowing I can easily hold my breath for at least one minute. Once I get on the redundant gas supply, the emergency is over, and I can signal my buddy and ascend. The stress is gone . . . UNLESS I'm worried about whether I have enough gas in my redundant supply!

(Of course, you are unlikely to find me at 130 feet on a single tank, or carrying my own redundant supply on a single tank dive. But the principle remains the same. If you are confident in your emergency procedure, stress should vanish quickly. If you aren't . . . )

 

[Captain12Pk]

Good point. I think you're right. You can do a pretty slow OOA ascent from 15 ft, but easier to control with 100# to work with.

If you were in deco at 130 ft, I think doing the best you can to get out of it on the ascent is good, but making the ascent without drowning is your first priority - then hope the boat's O2 bottle is ready. Seen a couple of failures on the latter but at least they were alive to deal with that.

Yep, could call it that way too. More air is always better for me.

This chart Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan shows for Catalina tanks...
13: 4.38" OD 12.8" long plus valve 5.7# -0.8# buoyancy empty
19: 4.38" OD 17.4" long plus valve 7.8# 0# buoyancy empty
30: 5.25" OD 20" long plus valve 13.7# -0.2# buoyancy empty
As heavy as my 19 is to walk around with in the Santa Rosa NM parking lot with 7 mil suit & lead, or climb out of the water with, the 6# difference is small in comparison to the total load, but it all adds up. How much do you want to carry?

Most divers I know don't carry any pony bottle weight tho, so at least I got what I got with me. Have been glad a couple of times.

See, I would suggest that the best thing you could do if you found yourself in 130fsw, a deco scenario, solo, and out of gas would be to take a good long hard look at your diving practices.

 

[Captain12Pk]

Not by any means criticizing your comment Don. Just trying to make a point about the proposed scenario.

K

 

[Blackwood]

See, I would suggest that the best thing you could do if you found yourself in 130fsw, a deco scenario, solo, and out of gas would be to take a good long hard look at your diving practices.

If you find yourself in that situation, the best thing to do is try to get yourself safely to the surface.

Hopefully you'll be able to take that good hard look afterwards.