Pony bottle vs. Spare Air?

[tankdiver]

i use both but im crazy redundant in my world of thinking more air is always a good thing when it comes to diving i dive an al 80 with a 40 slung and a spare air on my right hand side

 

[MaxPower]

All that aside, you should ask yourself why you think you need any of these items?[/quote]

I can't imagine a dive where redundancy wouldn't be wise.

 

[diverDano]

I will clarify the "HP" pony I was referring to....its from xs scuba here is the link...
XS Scuba Worthington Steel Cylinder Specifications

I posted hp, because the aluminums have a 3000psi rating, these are 3442psi.

Also, i meant the same size, being physically the same dimensions, height and circumference.

I actually dove an al40 as a bailout for commercial, this being so long, hard to manuveur, a st40 is way shorter and the same circumference, which, for me was the way to go. I just bought two, one for commercial side and one for the rec side. (and they were 200 a piece)

 

[Blackwood]

Don't let the extra weight of a pony change your mind to not carry one since the weight came of off the weight-belt

Not all of it. You should carry enough weight to compensate for using the pony (in other words, you need an extra 19CF worth of lead).

 

[DandyDon]

Originally Posted by willembad View Post
Don't let the extra weight of a pony change your mind to not carry one since the weight came of off the weight-belt

Not mine. It's not heavy in the water, but I don't change my weighting. My 19 cf tank is 1.4# buoyant empty, offset by the weight of the reg, and I don't want a weight problem if I use it, so I use the same lead.

Packing the luggage, tho - or climbing the ladder, the pony and reg are an extra 15# - and I feel it on the ladder. This does not affect my decision to carry mine on every trip and every dive below 60 ft, but it's still a fact.

 

[willembad]

That is a good choice diverDano. The reason I didn't understand was that the same physical size tanks (same tank for that matter) would contain ~23 cf of gas @ 3442 psig if it had 19.9 cf @ 3000 psig. The X5-40 is actually a little bit fatter than an AL40 (quite a bit shorter though)and more than an inch fatter than an AL19.

DandyDon, you are quite right. I should have said some of the weight came of the weight belt. I'm not sure which pony you use but these numbers are from the manufacturers websites:

AL19 = 8.2 lbs weight, -1.4 lbs bouyancy full, 0.1 lbs empty
That's 8.3 lbs extra weight out of the water.
FX23 = 8.6 lbs weight, -2.64 lbs full, -0.66 lbs empty
That's ~8 lbs extra weight.
X5-40 = 18.1 lbs, -6.3 lbs full, -3.3 lbs empty
That's 14.8 lbs extra weight.

I know I should account for the weight of the gas in the pony as well, but for the "average" pony we're talking 1.5 - 2 lbs, so I guess you could add that to the above numbers. I still agree that it's a small price to pay for having the pony with me

Willem

 

[DandyDon]

AL19 = 8.2 lbs weight, -1.4 lbs bouyancy full, 0.1 lbs empty
That's 8.3 lbs extra weight out of the water.

One site gives 9.3# for the tank. I think my full pony and reg with two hoses and an spg weigh about 15# on the scales.

 

[Scuba Crab]

At first glance the smaller size of the steel x5pony 40 at 5.4in dia x 18.75 in length verses the al40 at 5.25 length x 24.6in length Looks very apealing to be smaller and more compact. But the bouyancy of the steel 40 is -6.3lbs full & 3.3lbs empty The Aluminum 40 is -0.7 full & 1.8 empty making the aluminum almost nuetral in the water. There are allso a few pounds neg to consider for my regulator and sling set up. Basicaly there is no need to adjust my weight for boyancy with or without an aluminum pony. But if I were to carry a steel pony and adjusted my weight 6-8lbs or more to achive perfect bouyancy I am fine as long as I have the pony on my body. But If I mistakenly handed it to someone else in an emergency I have just lost 6-8lbs or more and could have problems keeping my self from having a safe accent jepordising my own safety.

For me I feel more comfortable having my pony setup to be closer to being nuetraly bouyant!

 

[divad]

glad to be apart

 

[offthewall1]

Spare Air is for extreme emergency only. 6 CF is only good for most panicked divers for about 30-40 breaths. Barely enough for a direct ascent the surface from 100 ft.

A Pony bottle (most commonly 30 or 40 CF) holds significantly more air and therefore will allow a diver adequate time to safely ascend and complete a safety stop of 3-5 minutes in most any recreational diving situation.

I can recommend a SpareAir for those doing shallow diving only (less than 60 ft.) Anything deeper I recommend a pony bottle mounted onto your primary tank.

Happy Diving.