Thinking of buying a pony bottle

[mkutyna]

With all things in life, "it depends."

For instance, if you're limited to 20' in depth, then the chances of you encountering DCS are extremely slim. However, there have been cases where freedivers get DCS without using any compressed air at all. They do many dives in a day to deep depths ( >60') for long periods of time.

Personally, while I enjoy free diving I prefer to keep it and scuba separated. Free dive before scuba or no free diving at all that day.

 

[azchipka]

Another option for you is the XS Scuba Pony Pack which I use often with my 40cf stage bottle.

XS Scuba Pony Pac Harness BC503 with reviews at scuba.com

 

[LeadTurn_SD]

There was another thread recently on this topic.

As long as you remember that once you've taken that first breath of compressed air underwater that the free dive instantly becomes a scuba dive, you should be fine... but my feeling remains that it is not a great idea to mix the two.

The real danger with mixing the two is that if you are free diving and taking an occasional breath from the pony to extend the duration of the dive, the natural reflex will be to hold your breath in between breaths from the pony.... which could be disasterous if you do it as you surface.

Interestesting fact: If you are a talented enough free diver, you can apparently get bent from free diving alone. It requires repeated deep dives with too-short surface rest intervals, and thus is beyond the abilities of the recreational snorkeler I guess.

Best wishes.

 

[BEM]

Some freedive information

United States Apnea Association (USAA)

 

[Reg Braithwaite]

I love free-diving, but always wish that I could stay down for a few minutes at a time, moving around and looking at the beautiful aquatic life, before heading back up to the surface. So I was thinking of getting a little pony bottle to help me achieve that.

I don't have enough experience to tell you that this is a dangerous idea. But looking at some of the other responses here, I would certainly think long and hard before using a bottle to take a few breaths of compressed air during a "free" dive to extend your bottom time.

Think of things this way. Imagine I am going Scuba diving and I make the following plan:

Take repeated deep, deep breaths at the surface. Descend while holding my breath. Continue to hold my breath at depth, but take air from my regulator when I can't hold it any longer. Surface rapidly without decompression of any kind.

I dunno what will happen, but it does seem to go against Scuba practice.

Anyhow, I have another idea for you. If what you love about free diving is the freedom of movement, would you consider monkey diving? Rig a single AL80 like a stage and skip the BCD, weight yourself so that your lungs are 100% in control of your buoyancy and go diving.

I have zero experience with this, and perhaps I am suggesting something even more dangerous. So do your research before trying it. But still, it looks like it may be what you're seeking...

 

[dumpsterDiver]

Okay so bad idea?

I often use a 30 cu-ft bottle to retreive fish from holes that were speared while brathholding when the the depth exceeds about 60 feet. Conventional wisdom would say that you should not freedive after a scuba dive.

Not too long ago I used a 13 cu-ft pony to dive to around 90 feet to retreive a fish and when I got back to the surface, I still had half a tank. Generally these scuba dives are very short, maybe 3-4 minutes, not much longer than what a really good freediver might be able to do. Generally I will take a break from freediving for 30 minutes if I use a tank, but this is NOT good practice.

If you use a scuba tank, you should not freedive anymore until the next day or so.

 

[paddler3d]

you should not freedive after scuba diving

One of my computers switches between SCUBA and FREE over the course of the day tracking my nitrogen load and off gassing.

Wouldn't that be the argument for not mixing the two in the same day?

I've had many a long weekend of mixing SCUBA and free diving. 10+ dives and 60-70+ free dives.

 

[muddiver]

I often use a 30 cu-ft bottle to retreive fish from holes that were speared while brathholding when the the depth exceeds about 60 feet. Conventional wisdom would say that you should not freedive after a scuba dive.

Not too long ago I used a 13 cu-ft pony to dive to around 90 feet to retreive a fish and when I got back to the surface, I still had half a tank. Generally these scuba dives are very short, maybe 3-4 minutes, not much longer than what a really good freediver might be able to do. Generally I will take a break from freediving for 30 minutes if I use a tank, but this is NOT good practice.

If you use a scuba tank, you should not freedive anymore until the next day or so.

I disagree about not mixing the two within a 12 hour period. If you follow a dive table or you use a diving computer, you will know where your nitorgen loading is and you should be able to plan repetative dives after a scuba dive without any problem.

If one uses a compressed air source safely during a free dive, just change your plan to scuba requirements, figure your residual group, wait the required period of time and continue free diving.

The new U.S. Navy Diving Manual has a new shallow water diving table that can be used for this purpose (page 2A-1 at the end of chapter 11) you can down load it at http://www.supsalv.org/00c3_publications.asp?destPage=00c3&pageId=3.9 it is the eighth item on the list.

 

[LeadTurn_SD]

I disagree about not mixing the two within a 12 hour period. If you follow a dive table or you use a diving computer, you will know where your nitorgen loading is and you should be able to plan repetative dives after a scuba dive without any problem.

If one uses a compressed air source safely during a free dive, just change your plan to scuba requirements, figure your residual group, wait the required period of time and continue free diving.

The new U.S. Navy Diving Manual has a new shallow water diving table that can be used for this purpose (page 2A-1 at the end of chapter 11) you can down load it at SEA 00C3 Diving Publications and Technical Documentation it is the eighth item on the list.

Hi muddiver,

My understanding about this problem only comes from reading over the past year or so, and so I may have this wrong, but:

I think the caution about about mixing scuba and free diving is not strictly from a repetitive-dive standpoint, but from an ascent rate difference between free diving.

With scuba, we are (hopefully) ascending at a rate less than 60 feet per minute; with free diving, the ascents are much faster. Double, triple the ascent rate of scuba?

The risk, as I understand it becomes "bubble pumping": On descent, excess nitorgen that is off-gassing normally from the lungs is recompressed and passes back to the arterial side. The rapid ascent following the free-dive then potentially allows the nitrogen to come back out of solution as bubbles, still on the arterial side (where it can't be off-gassed throught the lungs), and a DCS hit results.

I have not read (and it may not be known or fully understood) where the cutoff is as far as when it is safe/unsafe to free dive following scuba (as far as nitrogen loading), so I think that is why the recommendation for no free diving the same day as scuba exists.

Hopefully others with more knowledge will jump in and correct this if I have it wrong.

Best wishes.

 

[muddiver]

Thanks LeadTurn SD, I hadn't thought about ascent rates, therefore the 12 or 24 hour rule akin to ascent to altitude after diving takes presidence.