Pony bottle size for NC wrecks?

[Web Monkey]

The answer is a definite "maybe"

It depends on your consumption rate, which will certainly go up when you discover that you're at 130 ft and Something Bad happened.

If you're diving deep and you're going to carry a pony, you might want to go for a 30 instead of a 19. It's not much bigger or heavier. It would also give you a chance to do an additional stop at 60 for a minute or so.

FWIW, I always carry a pony when I'm traveling and get a random unknown buddy. Some are great and would happily share air, some vanish at the first opportunity and some hoover their air down and then want yours. Having a spare 30 Cu Ft makes all of that a lot less stressful.

Terry

OK ok, I don't want this to turn into some psycho-masochistic thread about whether or not PB's are good/bad/ugly/give unneeded confidence etc. etc. Point is, I'm diving in North Carolina in July, and I'm not diving with my tried and true girlfriend who I trust my life with, so I'm aiming to be a bit more self-sufficient.

So, is a 19cu ft. enough for depths to 130 feet in and OOA emergency to get to the surface with a 3 minute safety stop?

Could someone else please advise me on what regulator I should get for this setup. Thank you so much for your help.

Please be courteous and don't highjack this thread into a humongous debate.

 

[alemaozinho]

Yes it,s enough but i also would run this set up with a good regulator SPG set up. peace

 

[Snowbear]

So, is a 19cu ft. enough for depths to 130 feet in and OOA emergency to get to the surface with a 3 minute safety stop?

Enough what? Gas? Well, maybe. Then again, maybe not. Better ask Mr Murphy about it...

 

[lamont]

If you assume a 1.0 cuft/min/atm SAC rate, 1 minute spent at depth, a 30 fpm ascent rate, stops for 1 min at 30,20,10 fsw -- then you would need 22.6 cu ft of air from 130 fsw:

1.0 * (130 / 33 + 1) * 1 min = 4.9 cu ft
1.0 * (130 / 66 + 1) * (130 / 30 mins) = 12.9 cu ft
1.0 * (30 / 33 + 1) * 1 min = 1.9 cu ft
1.0 * (20 / 33 + 1) * 1 min = 1.6 cu ft
1.0 * (10 / 33 + 1) * 1 min = 1.3 cu ft

 

[jonnythan]

It's probably not enough from 130 if you go 30 fpm and do a 3 min safety stop, as lamont pointed out.

 

[MXGratefulDiver]

Not enough info to give you a definitive answer.

In order to know if it's enough, you'll have to first know your current SAC rate.

If you have any difficulty keeping cool under stress (which is most of us except maybe a few James Bond types) ... double it.

Then perform the Lamont's calculations.

At any rate, it's better than a Spare Air ...

... Bob (Grateful Diver)

 

[armyscuba]

I dive with a 30 cu. ft. pony..have deployed it during rescue ascents (Training only) at 140 ft. and it is very well suited for the mission. Size wise..not much difference from the 19 to the 30..if Your going deep. I think You would be happy to have it as a backup.

 

[paulwlee]

I don't agree that there is not much difference between the 19 and 30. The 30 is almost twice as heavy as the 19cf pony. It is almost half the weight as an AL80.

If you plan on mounting it on the side of your main tank, then the 30 isn't going to work so well. The 19cf on the other hand, works quite well for this.
If you are slinging it to your side in a manner similar to a stage bottle, then both work, and the size difference won't matter any more.

At any rate, if you plan on diving to 130ft, 19cf is going to be pretty tight if you want some time to sort things out, a normal steady ascent, and safety stop. The 19cf would work out OK up to maybe 100ft for this.

 

[hex92]

I have a 30 and I'm relatively happy with it. But you may want to consider the bouyancy characteristics. My Catalina 30 is -2.5 lbs when full. A luxfer 40 is -0.9 lbs. I think the 19 is -1.5 lbs. If you wear it on your back it may end up causing your rig to rotate a bit. I have this problem when diving wet (but not dry...for some reason).

If you buy a 40 now you will have it later when you may decide to get into technical diving.

That said, check out the picture I uploaded on pony selection. It shows that the 19 should be sufficient for the diving you will be doing off NC.

 

[Lead_carrier]

Carry a 30 or 40. That should give you pleny of air to do a normal ascent with a safety stop from any recreational depth.