Saving Old Seagulls

Hi Robin, this is what i used to use to scrub the bottom of my yacht. It just uses a couple of 12V diaphram compressors, dive hose & a modified snorkel that has a non return valve in it. Its a total loss type system & works well to 12Ft depth, it draws about 10Amps on a 12V battery. Dont have the yacht any more so use it to catch crayfish. Total cost $270.

I'm liking that alot and would love one for the same reason (working under the boat, not catching Crayfish )

Some (daft) questions
- What application are the pumps made for?
- Why two pumps. They are in parallel to supply the right volume of air?
- How is the delivery of air matched to your requirement for air?
- What happens when you breath out?
... or do you blow up till you burst?

fastjedi wrote: - How is the delivery of air matched to your requirement for air?
- What happens when you breath out?
... or do you blow up till you burst?

The non return valve release the excessive amount of air and the air you release when you breath out. About the rest someone has tried that would answer!

What application are the pumps made for?

I have a few pumps the exact same as the blue one in the above pics. I bought it in ChongQuing China at a place that sells live fish transort equipment. Same pumps are in every live fish market in asian by the dozens. One of those pumps I installed in a trout pond and it has been running air down to a 4 foot depth and thru a fine stone for 3 years straight. Nice pumps IIRC I paid 7 dollars a piece for them, and had the feeling I was making someone's day. If you want I can dig out the box and give you the manufaturers contact info.

Be careful of what you breath!!!

The black pump is a Vac/Pressure pump capable of 20Psi, started with that only but im a air hog so fitted the second one. The blue pump is an aquarium pump 10Psi. These are diaphram pumps so there is no oil involved. As some one has already stated the snorkel has a purge valve in the bottom for the escape of exess air & when you exhale. The black pump cost $150 from America the blue pump $45 from Hongkong. The grey cylinder is 50MM PVC pipe with end caps (not glued on but pressed on & 2 stainless screws locking the caps on) this chamber removes the harsh compressor pulses in the line. As some one said beware the air you breath, make sure the pump is in clean air (no engine exhaust fumes in the vicinity). There is more expensive 12V dive compressors around, here in Australia there is Power Dive made in Queensland. The Double deck model will suport 2 divers, price $2500 Aust. Single deck for one diver about $1500. Just Google Power Dive for more info on them. The yellow hose is Divers hose.

Thanks Daryl - thats an impressive bit of engineering. Beyond my skills - I would probably end up like Norman Wisdom in that great od film where he is a diver (Puckle I think was his name) and the dive gear pumps him up like a balloon.....
Will keep holding my breath - although there is a mini scuba kit on the market which would be handy for the bottom of the keel.
Cheers,
Robin

Be careful with such attempts. I have done scuba diving lessons and I can say that it will be dangerous to stay for some period of time under 10 meters. This is because of the N2 dissolved in the blood.
In addition if you breath underwater when you start going up to the sea level you have to exhale all the time. This is critical. Otherwise the lungs may rupture.