Pony as a replacement for shore side oxygen tank.

[Roy_W]

My wife and myself are nearing 200 dives each, we are recently certified CMAS Level 3 divers and have experience in Lakes, the Sea and Liveaboards.. We have just recieved new dry suits and are currently in the process of gaining experience with them..

Our next goal is to start diving outside of the constraints of our club. Even withing a club dive we normally dive as a buddy team, so nothing new there.

Eventually when we dive on our own this will mean that we have no club material at our disposition and my question related to this situation.
We recently had a conversation where the suggestion was given that if we consider doing the dives outside of the constraints of the club that we should do our Advanced Nitrox course as this would allow us to eventually carry a 7l 100% oxygen pony on our dives. Important : the idea is NOT to use the pony for deco use. The idea behind the pony is to carry emergency oxygen with us rather than have a tank on the shore. Obviously it wouldn't be capable of providing a 15l/minute flow rate , as is expected , but it would definitely be an immediate source of oxygen in the event of an emergency ( the shore is not always just a minute away).

What are your thoughts on this approach ? What alternative methods do you use to replace a shore/boat available oxygen kit ? Do you actually dive with the expected medical/safety gear on the shore side. Leaving a couple of hundreds/thousands worth dollars/euros of gear on the shore whilst diving is not an appealing idea.

Cheers

 

[Grantt]

When I do shore dives, even solo, I have a medical and O2 kit in my car. I would not carry an O2 tank, for the purpose of emergency O2, on a dive. If you are looking this deep into contingency planning for shore dives, maybe invite another friend along to hang out ashore in case emergency assistance is required.

 

[rhwestfall]

If you don't know exaxtly what you are doing, then no...

If you have technical training and if you have/use O2 for deco, you could start here that would let you connect a medical regulator to a SCUBA tank...

DGX Gears Adapter: DIN to CGA-870 Pin Index POST

The DGX DIN to Pin index Oxygen adapter lets you connect an emergency medical oxygen PIN Index Regulator to a common 200 BAR DIN cylinder valve.

www.divegearexpress.com

Then, if you have training in O2 administration:

A demand regulator kit for oxygen administration...

 

[rongoodman]

It sounds a really good way for somebody to kill themselves by breathing off the "pony" at a depth where its contents would be toxic, IOW, a very bad idea. (What kind of dives are you doing that you think you need to keep an emergency O2 supply with you? Do you dive at such remote locations that emergency services are not available?)

 

[davehicks]

Leave the O2 in the car when shore diving. To carry this with you is removing the option to carry a far more useful pony bottle with a breathable mix you can use in a far more likely emergency incident such as OOA or Reg failure.

 

[Lorenzoid]

Obviously it wouldn't be capable of providing a 15l/minute flow rate , as is expected , but it would definitely be an immediate source of oxygen in the event of an emergency ( the shore is not always just a minute away).

Just my opinion, but I would suggest making it to shore, even if it takes 10-15 minutes, and THEN retrieving the oxygen from your car to treat any possible DCS symptoms. I don't recall the statistics on how fast DCS symptoms manifest after a dive, but my vague recollection is that it often takes quite a few minutes--maybe you won't see any symptoms for 10, 20 or 30 or even more minutes after surfacing--by which time you will probably be on shore and back to your car.

 

[Beau Holden]

What are your thoughts on this approach ?

O2 carried on a dive is only for decompression. I am not going into in water re-compression.

What alternative methods do you use to replace a shore/boat available oxygen kit ?

My phone and calling 911 in the US.

Before making my decision, I would read the following articles from DAN.

Decompression Illness

Decompression illness is related to bubbles in body tissue or blood vessels. Read about the causes, symptoms, and how to respond to a suspected case of DCI.

dan.org

Decompression Sickness

Decompression sickness (DCS) is an unwanted outcome of diving. Measures to mitigate the risk of DCS have to be a part of every dive.

dan.org

allow us to eventually carry a 7l 100% oxygen pony on our dives. Important : the idea is NOT to use the pony for deco use. The idea behind the pony is to carry emergency oxygen with us rather than have a tank on the shore. Obviously it wouldn't be capable of providing a 15l/minute flow rate

How close is your emergency services? This where I would start on determining the size of O2 tank I would have for emergency purposes. Do want 15L/minute or something else?

I think it could be a good idea to have one. However, in 20 years of diving I have only seen one case where one was used at the dive site and it was a AGE event.

 

[SlugLife]

Our next goal is to start diving outside of the constraints of our club.

In theory, you should have zero dependencies on this club. Them having oxygen on shore is a nice bonus, and possibly rescue divers nearby. However, ideally, the two of you should be fairly safe in the water, especially after 200 dives.

If you wish to pursue safety, I'd recommend going the "self reliant" route. In other words, redundancy. It's better to not have an emergency in the first place. Buddy-separation or a buddy that can't help you (due to their own problems) does happen.

• Redundant Air - Ideally, this is a tank and regulators detached from your main air-supply. Typically a pony bottle. I consider 19cu ideal for recreational use. 13cu is good for travel. 6cu is small but don't delay your ascent. 30cu and 40cu good for technical diving, but perhaps a little big and in your way.
• Redundant Buoyancy - For this, I use a DSMB. If your BCD fails, you could always partially inflate a DSMB, and dump air as you go up. On the surface, you can use it like a "pool noodle."
• Proper Weighting - Imagine you jumped off a boat, with air off, BCD deflated. Would you die? Very unlikely if your properly weighted. Being properly weighted is a form of redundancy. It also help in a scenario like a BCD failure.
• Cutting Devices - Multiple cutting devices, at least once accessible to each hand, in case the other gets tangled.
• DAN Insurance! - Aside from financial protection, they can also get you PROPER scuba-specific medical assistance and advice quickly.
• Backup lights, masks, dive-computers, etc - These are really only necessary, if you would have difficulty surfacing safely without your primary working. Generally, I only bother with this during night-dives
• Save a dive kit! - Ok, not a safety thing, but some tools, o-rings, bungie, batteries, etc.

^ Once you've addressed most of the above, maybe then I might think about other stuff like having oxygen on shore. NOT on your person. While it would be nice to have everything on your person, you'll eventually start to look like a Christmas-tree, and all the extra stuff you bring actually becomes a hinderance, entanglement hazard, or danger to yourself.

 

[Nick_Radov]

Unless you've completed technical diving training covering oxygen toxicity risks and safe gas switching procedures it's really not a good idea to carry an oxygen stage or pony bottle when diving. You don't need it for recreational diving, and it introduces additional hazards and equipment complications. When I do recreational shore dives, I keep an oxygen stage bottle in my car. The odds of actually needing it are extremely low, and if you do need it then taking a few extra minutes to swim to shore is unlikely to make a difference. If you're really worried about the time factor, then I would suggest using a DPV so you can get back to shore faster instead of trying to haul the oxygen around in the water.

 

[Roy_W]

Some interesting respones, thank you. I will give back some feedback when I have had the time to discuss with some of my club members. I like to challenge them on their choices ;-)

To reply to 2 points though.
: Yes, we are very well aware of Oxygen Toxicity and ppO2 limits. Especially 100% oxygen, I agree that the 6m limit is not a joke.... We are certified to 60m so we have definately gone through the training and theory. This is also the reason for us considering the Advanced Nitrox course.
: We are about a 5 minute helicopter ride ( presuming it is available and can land relatively close by, or a 40 minutes drive from a chamber.


Oxygen kits are expensive, especially the larger tank sizes like we have at the club. I would be very surprised to learn that most divers, diving outside of the constraints of a club/dive shop actually possess one. For those that do have one and leave them in their car, what size of tank do you have. For those that don't , what is your procedure in the event of an emergency. Is it just to call emergency services and wait ( I personally don't like this idea at all)...

When I look at many of the videos on the web, Malta and Bonaire most notably, I see divers in little jeeps driving around with 2 tanks in the back and just getting into the water where ever they want/can.. None of them appear to have any Oxygen/Medical equipment at hand. What are their contigency plans ? How are they taught to deal with emergencies ?