DIY Underwater Breathing Equipment

[bikedaft]

I might have been tempted as a youngster to give the old man a bit of a fright for a laugh

surely it would be rude not to? i would certainly be waiting for them to do that... wee toerags. wonder where they get that from ;-)

 

[Lon nan Gruagach]

Oh, and another thing about pump volume... at least double your breathing requirements since you dont breathe in all the time..

 

[agurney]

When you snorkel normally you do exactly this and there isnt a problem. reason being that sure you inhale some of the air you just exhaled but..., 2 buts in fact...
1 the volume is tiny compared to the amount you breathe
2 the CO2 concentration in normally exhaled air is quite small and there is still a fair bit of oxygen left in it too.

.. but with normal snorkelling you will usually take a few breaths on the surface before heading down again (having built up quite a bit of CO2 that needs to be purged)

bonus, as has been mentioned is that the incoming fresh air will also purge some/all of what you breathe out.

edit add:
Beware though, the first pump I see is rated at 320 l/hour and 3m depth, not sure if these are concurrent (many pumps will do one or the other). A 70 kg human will breathe 7.5l/minute at rest up to 65l/minute max exertion (source google search leading to some technical article on miners).. 320 l/hour is borderline

The pump doesn't need to powerful enough to inflate the lungs, it's just to make clean air available in the supply pipe. You would be able to suck more than the rated volume of air through the pump if it came to it.

Interesting idea, I'll maybe have a play around with an old regulator

<snip>

 

[agurney]

Oh, and another thing about pump volume... at least double your breathing requirements since you dont breathe in all the time..

and increase by 30% if you're going to hang around at 3M for any length of time

 

[lw395]

Probably worth a thought about the type of pump.
It needs to deliver air which is clean enough to breathe.
I would be wary of any old bit of plastic hose too.
Also think about keeping the hose clean, you don't want to be breathing in a lot of spores or whatever.
A nice sealed regulator system might be worth it?

I do know someone who used to use a normal scuba set with the cylinder on deck and a long hose to the mouthpiece.

 

[nigelmercier]

So much discussion, when clicking the link in my Post #14 would give you all the info you need! All too lazy perhaps?

OK, details copied below:

This is the hookah I bought when I was in the USA: http://r.ebay.com/3VOPqD
For DIY, this is the pump that came with the hookah: http://www.boyuaquarium.com/En_ArticleShow.asp?ArticleID=2052

The regulator is a standard model that has been adjusted to free-flow. You could use a snorkel with a purge valve instead, but I find them uncomfortable.

It works really well, but needed some modifications to make it ideal:

• It is very noisy, and glides around the cockpit. Mounted on board with foam underneath; I may box it in.
• The hose does not have a QD, I'm in the process of fixing this with air-line fittings.

 

[DownWest]

I read a book by Peter Keeble on his war time expériences in diving (find it if you can) They used gas masks on hoses from standard diving compressors for shallow work.
The compresser linked is a diaphram type, so fine for oïl free breathing.

 

[alan_d]

Yachties in the US and Australia seem happy to use commercial Hookah sets (try Googling), but British divers seem to regard them as work of the Devil.

 

[duncan99210]

This British diver doesn't regard them as the devils work.... I do wonder about some of the diy lash ups I've seen talked about but decent hookah gear is a good alternative to conventional scuba kit in reasonably shallow water.