DIY Underwater Breathing Equipment

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Harry Brown

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The following is an extract from June 2016 Yachting Monthly Magazine (page 10). A letter submitted by Nick Mines.


Frustrated by the difficulty in checking and cleaning underwater when unable or unwilling to haul out, I investigated the underwater breathing equipment on the market.
Although I am a qualified BSAC diver, I am reluctant to carry tanks and the paraphernalia involved. My solution works well up to a depth of 3m, which is all I need. I have spent hours burnishing the propeller and removing barnacles in the Caribbean, and with a wet suit in home waters.
I use a Hozelock pond aerator pump, a filter, some hose and a snorkel (the type which can be ‘purged’), which has been modified to take a Hozelock hose connection.
The inverter runs the pump, the hose I use for filling tanks and washing decks.
It’s probably frowned upon by the diving establishment, but it works for me. I have not had to use it for cutting rope from the prop but it would be invaluable in that situation too.

Click picture twice to enlarge
Nick.jpg
Does anyone have any information on exact components used and how Nick attached the Hozelock Aerator, Filter, and Hose to the Snorkel?
I'm also interested in details if anyone else has made anything similar?

I understand the risks! Lets keep this thread DIY Underwater Breathing Equipment.
 
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I'm also interested in doing something like this. I'm PADI certifed and feel the need to change/check underwater anodes, scrub etc but don't want to carry tanks and such. C-Pro have smaller setups - mini b - but they run to £700. Years ago there was a surface device - called a SWEBA I think, that basically used a beach ball type inflatable to act as a ballast to a supply of air provided by a crew member with a handpump. The 'beach ball' was attached to a mouthpiece/regulator.

I guess the ventable snorkel allows air to constantly blow from the snorkel when the user isn't inhaling - acting as a crude regulator.
 
Sea_Spray said:
I guess the ventable snorkel allows air to constantly blow from the snorkel when the user isn't inhaling - acting as a crude regulator.
Click to expand...

So you inhale (relatively) fresh breathable air through the snorkel with the use of a pump but where do you exhale the CO2? Certainly not in the snorkel because you will inhale it back the next time.
 
cmedsailor said:
So you inhale (relatively) fresh breathable air through the snorkel with the use of a pump but where do you exhale the CO2? Certainly not in the snorkel because you will inhale it back the next time.
Click to expand...

CO2 will be expelled through the purge valve when you exhale, assisted by the air from the pump, by the time you take the next breath, the CO2 will be long gone.
 
cmedsailor said:
So you inhale (relatively) fresh breathable air through the snorkel with the use of a pump but where do you exhale the CO2? Certainly not in the snorkel because you will inhale it back the next time.
Click to expand...

Just breathe out of the side of your mouth or through your nose.
PADI divers should have been taught to sip airfrom a free-flowing regulator?

Using a second stage reg would be more elegant, but they tend to need a few bar to work. So you need a more powerful pump.
You can buy such 'hookah' systems but they are expensive, >£500 AFAIK.

Third world divers will breathe off the end of any old tube from a compressor...
 
cmedsailor said:
So you inhale (relatively) fresh breathable air through the snorkel with the use of a pump but where do you exhale the CO2? Certainly not in the snorkel because you will inhale it back the next time.
Click to expand...

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.

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

see http://www.hozelock.com/our-products/aquatics/air-pump/ for pump details
and http://www.molecularproducts.com/pdf/technical-library/A%20Guide%20to%20Breathing%20Rates%20in%20Confined%20Environments%20Technical%20Article.pdf for breathing information


For fittings, I would use the supplied hose and cut into the snorkel using something from:
340997654_666.jpg
 
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Seems a complicated solution. Pony cylinder with 1st & 2nd stage reg on a lanyard worn bandoleer style gives 20 mins+ at 3m. Works for me, anyway.
 
Coincidentally I have just returned from Boulogne where a French yacht was being examined underwater by a diver using a small pump approx the size of a lead acid battery with a hose attached. The hose allowed him to get full access to the 40 ft yacht & he only seemed to be using a mouthpiece & goggles. The hose seemed to be about 25mm diameter.
The pump was supplied by power from the yacht so I assume 12 v. The pump was surrounded by a tubular frame & a chap on the pontoon was operating it, although that only seemed to be turning it off & on when the diver dived/surfaced
The whole setup seemed light, compact & quite useful. It did not appear to be a home made unit though, so probably expensive
 
kid up top with a dinghy pump. hose. schnorkel with valve

i've been meaning to try this for years. at last the kids are old enough to pump...
 
bikedaft said:
kid up top with a dinghy pump. hose. schnorkel with valve

i've been meaning to try this for years. at last the kids are old enough to pump...
Click to expand...

Yes, but are they now old enough to go for the inheritance before you get to spend it before they get their hands on it.
Does not take much to"accidentally" put the pump on suck instead of blow !!!!

I might have been tempted as a youngster to give the old man a bit of a fright for a laugh
 
cmedsailor said:
So you inhale (relatively) fresh breathable air through the snorkel with the use of a pump but where do you exhale the CO2? Certainly not in the snorkel because you will inhale it back the next time.
Click to expand...
How do you think mouth to mouth resuscitation works?
 
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