snorkeling with a pony

[I'm sure this is going to generate some flames but, really, this isn't a troll. Please try to be constructive when responding.]

Has anyone out there done any shallow snorkeling with the assistance of a pony bottle? As in, diving down and (at depth) taking a breath from the pony bottle to extend your time below? I know all about the pressure differential being most pronounced as you approach the surface, and that you can get an embolism holding a breath from only a couple of feet down. Ascents would naturally have to be with an open airway a la a CESA. I realize this is off the dive tables given that it would involve many repeated descents/ascents, albeit from no more than ~15fsw. I can't imagine that there'd be much nitrogen loading as we're only talking a single breath or two before a return to the surface. So. Is this phenominally dangerous? Something someone out there wants to admit to having done, either in the forum or in a private message?

Wouldn't that be considered a bounce dive? Which seems to be frowned upon by just about all agencies...

Aloha, Tim

If you were to do this you would really still have to limit your rate of accent to 30 ft/min. For your 15 foot dive
that would mean taking 30 seconds to come up from the bottom. I think the requirement to come up slowly nagate any advantage to having air with you.

And then have the bottle and reg and some way to hold it removes the advantage of free diving the biggest of which is the ability to move very fast and be free of equipment.

I think you'd have the worst of both worlds

One more arument: If this is such a good idea why not take a lager bottle, say like 80 cu ft.
and stay down for an hour?

sdr_adam:

[I'm sure this is going to generate some flames but, really, this isn't a troll. Please try to be constructive when responding.]

Has anyone out there done any shallow snorkeling with the assistance of a pony bottle? As in, diving down and (at depth) taking a breath from the pony bottle to extend your time below? I know all about the pressure differential being most pronounced as you approach the surface, and that you can get an embolism holding a breath from only a couple of feet down. Ascents would naturally have to be with an open airway a la a CESA. I realize this is off the dive tables given that it would involve many repeated descents/ascents, albeit from no more than ~15fsw. I can't imagine that there'd be much nitrogen loading as we're only talking a single breath or two before a return to the surface. So. Is this phenominally dangerous? Something someone out there wants to admit to having done, either in the forum or in a private message?

Click to expand...

Once you breath off of compressed air at depth you are scuba diving and susceptible to all of the physical effects and dangers of diving.

When you dive while snorkeling you hold your breath and on scuba you don't. I would imagine that it would be incredibly dangerous to try to combine the two.

"Let’s see, was that a 1 atm breath or a 1.5 atm breath? Hold it or exhale? hummm?"

Sounds dicey to me.

Jeffrey

I can't see that this would be all that dangerous, assuming you stayed shallow & didn't hold your breath upon ascending. But what would be the point? Why not just scuba dive?

Heck, why not just get a hooka rig?

This sounds like a good application for a hookah.

I don't see this as a big problem from a DCS perspective. Obviously lung overexpansion injuries are a big concern but ignoring them for the moment, what are the physics of the dives? I am assuming very shallow dives, in the 15ft range with each of the "dives" being on the order of 1 to 2 minutes and no previous deep dives. Doing this after one or more deep dives is a totally different matter and not a good idea at all. N2 loading is going to be very mimimal given the depth and limited time at depth and considering the surface interval for off gassing during the snorkel portion of the outing. DCS requires a considerable amount of N2 in the body, something not possible with this type of dive. It is true this would be a bounce dive but the type of bounce dives that are of concern have greater depths and N2 loading than is possible with this snorkel/dive.
My major concern would be lung overexpansion. It would be very easy to get confused on wheather the breath you are holding is compressed or not. One mistake could be very very bad.
I think if it were me, I would opt for an old plastic back plate, no bladder and a small tank-20 or 40 cf and just do a mini dive, surfacing to travel between points of interest if necessary. That's almost snorkeling and most likely a lot safer in the end. If I am going to carry the stuff to the water, I might as well get some bottom time in.

Bad idea.. either do it as a dive with an Al80 or do it as a freedive. Too much potential for screw ups.

What you're really doing is a short little dive with a tiny tank.