Home Made Breathing App

[dondmcg]

I do not desire to do anything really stupid, so I want to post this question. I am aware that there will be some that just say no to anything related to this subject and those are not the people I am searching out. I am hoping to get respectful responses with fact based informed answers to the responses (if no then why? What is missing? Suggestions to make the endeavor realistic or not possible/reasonably safe because...)

I need to repair a broken mooring. It is a helix anchor and the chain broke loose. I need to detach the old chain and put a new one on. It is in 8 feet of water at low tide. I can easily free dive down but have to quickly re-surface. I do have a padi cert training but getting re-certified will take time, not an experienced diver.

Does anyone see any complications with taking a (brand new) hand sprayer for back yard use as a supplemental breathing app just to get a few more seconds maybe a minute longer? I would have light weights to counter 2 gallon tank bouyancy.

The sprayer has no compressor just a hand pump lubricated with grease. Air quality issues?

I basically plan to free dive but as my air runs out take a few “puffs” from the sprayer that has hand pressurized air, released by pulling lever, to extend my underwater stay and finally take a breath from the sprayer to return to the surface ( exhaling along the way ).

I will test the length of time in a pool at 4 feet that I can remain submerged and do multiple dives ( pumping in new air each time ) with the tank on-site to free the old chain and attach the new one.

Would never do alone.
Would never try in at a depth greater than 8-9 feet.
Intend to repeat exercise to complete task no more than four or five times if necessary.

Is there anything terribly wrong with this besides the obvious response: just rent scuba gear?

 

[tursiops]

You've answered your own question....air quality issues.
There may be technical issues too (what kind of pressure does the aprayer provice?), but they are irrelevant if you don't want to put unclean air in your lungs.

 

[tbone1004]

yeah I wouldn't do that... If you have a padi cert, they don't expire so you should be able to rent some equipment with no problem.

Let's use a standard 2 gallon sprayer
The sprayer has to be pumped up to something above the ambient pressure of 9ft of water, which isn't inconsequential, but it's about 40psi for normal pump sprayers. It will experience about 10psi of pressure at that depth, so you have 30psi of usable pressure before it implodes. It will displace 2 gallons of water, or about 9lbs, so you have to strap 9lbs of weight to it just to get it to be neutral in the water. 2 gallons is about .25cf, and you have 2bar of pressure to work with, so about .5cf. Normalized for that depth, it is about 0.35cf. Working underwater, you can expect about 30 seconds of breathing down there. The biggest risk/concern is the flow rate through that nozzle and whether it is actually enough to get a breath off of, and then gas embolism since you are more than deep enough to experience a lung overexpansion injury breathing compressed gas.

 

[Charles2]

Besides the air quality issues, two gallons of air, even at 50 psi, will only last the average diver about a minute, maybe two. It's too early in the morning to do the math.

 

[redacted]

PADI certs do not expire.

 

[Neilwood]

As suggested above a few times, just rent the scuba gear. Far safer and probably only slightly more expensive. The home-made apparatus scares me.

Might be worth reading over the OW course materials just to refresh your knowledge but for a short duration dive, you will probably be ok without recertifying. Remember that recertifying is not mandatory just advised.

Either that or get a mate that does dive and has the equipment to do the dive and pay him with a few beers or beer tokens.

 

[Doby45]

I am just waiting for someone to recommend a tender stay up on the mooring with a bicycle pump.

 

[2airishuman]

I do not desire to do anything really stupid, so I want to post this question. I am aware that there will be some that just say no to anything related to this subject and those are not the people I am searching out. I am hoping to get respectful responses with fact based informed answers to the responses (if no then why? What is missing? Suggestions to make the endeavor realistic or not possible/reasonably safe because...)

I'm playing along, so I'll skip the sermon.

I need to repair a broken mooring. It is a helix anchor and the chain broke loose. I need to detach the old chain and put a new one on. It is in 8 feet of water at low tide. I can easily free dive down but have to quickly re-surface. I do have a padi cert training but getting re-certified will take time, not an experienced diver.

Does anyone see any complications with taking a (brand new) hand sprayer for back yard use as a supplemental breathing app just to get a few more seconds maybe a minute longer? I would have light weights to counter 2 gallon tank bouyancy.

Let's do the math. 2 gallon tank is 0.25 cubic feet. They can be pressurized to about 30 PSI, and you'll lose 4 PSI to depth. Skipping some of the intermediate steps, you'll have 0.5 cubic feet of air to breathe. When doing things underwater that require effort, I use around 1.25 cubic feet of air per minute. So the sprayer tank would ideally add maybe 20-25 seconds to my dive.

Then there's the problem of how you're going to deliver the air in a controlled fashion, and how you're going to attach the tank to yourself. You would need approximately 17 pounds of lead to counter the buoyancy of the tank.

So, that's the engineering problem, and it's more than you might think even when you leave the very serious safety problems out of the equation.

Is there anything terribly wrong with this besides the obvious response: just rent scuba gear?

1) risk of lung overexpansion injury when trying to inhale pressurized air without a demand valve (aka regulator). I see this as the most serious risk although the remaining ones aren't trifles either
2) lack of an air reserve for dealing with any problems, such as entanglement of the gear in the anchor line or things like monofilament that are tangled around the anchor line.
3) risk of being unable to ditch your 17 pounds of weight in an emergency, particularly if not using actual diving weights and belts
4) lack of (recent) training
5) no 2nd diver in the water to help you if there are problems

 

[DogDiver]

Darwin at work again.

 

[NYCNaiad]

I totally agree with @2airishuman. You'll only be adding seconds to your dive & the risk of a lung over-expansion injury without a demand valve is a very real one in addition to the other issues mentioned above. There are a number of divers in LI. If you don't feel comfortable doing a scuba dive yourself, maybe offer a little money to a local diver to help with this?