Looking to purchase a pony tank.......

[DiverDMD]

I am located in MA, most dives are in the 30-50' range with an occasional 80' scallop bed boat dive.

My interests are lobsters, scallops and flounder, thus a hunter, nothing else........

Now before we have lectures about why and why not to have a pony tank or the pony tank vs. spare air, please refrain to just answer my question:

If you dive with a pony tank, from your experience which size in cubic feet do you think would be more appropriate in my situation?

Thanks in advance.......

P.S. I have done searches, but they turn ugly, so please be nice......

 

[muddiver]

I have found the 13 cubic foot cylinder to work well in the 0' to 100' range for emergency ascents only. It is small enough to strap to the side of your main cylinder, back out of the way, yet it has enough volume to get you to the surface at a safe ascent rate of 30'/min.

You can probably get by in the 30'-50' diving range with a 6 cubic foot cylinder, but that is as small as I would consider to the depth of 50'.

 

[Dr Wu]

Now before we have lectures about why and why not to have a pony tank or the pony tank vs. spare air, please refrain to just answer my question:

If you dive with a pony tank, from your experience which size in cubic feet do you think would be more appropriate in my situation?

I would get the one with zero.

That sounds about right for very shallow dives around underwater obstructions.

 

[dumpsterDiver]

It depends on what your piorities are. Do you want the lightest possible rig or a heavier one with more safety? I dove 170 ft yesterday solo with maybe 8 minutes deco and I used a 13 cu-ft pony bottle. If my diving 80 ft or less and the risk of entaglement was small, then a 6 should be fine for a direct ascent. I often use a 6 cu-ft pony down to 130 ft, no deco diving.

There is no correct answer. The proper method is to assume a breathing rate, assume the time it will take you to get off the bottom, assume an ascent rate and assume any stops you would like to make. Then add any safety factor you wish and then pick the smallest bottle that will allow you to live if your assumptions were correct.

I own a 6,13,14 and 30 cu-ft bottles.

 

[Crush]

Now before we have lectures about why and why not to have a pony tank or the pony tank vs. spare air, please refrain to just answer my question:

If you dive with a pony tank, from your experience which size in cubic feet do you think would be more appropriate in my situation?

Hi DiverDMD,

I recently commented on people not being able to stop themselves from screaming "No" to pony bottles at http://www.scubaboard.com/forums/5198193-post32.html - you will find it is the same people, over and over. They are typically not able to think outside their training. They have already responded to your OP.

In http://www.scubaboard.com/forums/5086381-post8.html I suggested that you should choose a pony bottle size based upon rock bottom times. I would suggest in the 30-50 foot range a 13 cu ft tank would be ample, but you might want a 19 cu ft tank for dives below 90 feet.

In general I would recommend slinging a pony rather than mounting it on my main tank (see Stage/Deco Straps and Hose Retainers by Dive Rite - Dive Gear Express), but I have never gone hunting underwater and am therefore unsure as to whether slinging a tank might interfere with your hunt.

Happy hunting!

 

[spectrum]

From what you describe I'd go for a 19. Once slung it's invisible and there is no real $$ saved going any smaller. Better than opinions I'll suggest you run the numbers for the dives you contemplate. Here is an old post where I did such a tally.

Pete

 

[DiverDMD]

Thanks guys.......