Hookah Diving

[fishermantwo]

I would disagree that 50% of boat owners in Oz have a hookah set up. I don't know of any.
However I have always just used snorkel for boat cleaning. If you are patient you can do a bigger boat over several sessions. Currently mine is done every day but that is just weird and A/F doesn't last long. And of course it must be good exercise. I have a scuba tank but find it more trouble than it is worth for hull work. Good for mooring work though. olewill

Actually I said 50% of the local yachties own one. I did a pole. So out of the 20 boats 10 have them. Another has tanks but used to have a hookah and regrets selling it.

[davidjackson]

I'm assuming that some sort of basic training is required?? A simple understanding of Boyles Law (pressure-volume relationship) shows that there is the greatest change in volume in the shallows. A full set of lungs at 2m, breath held, would have expanded by 20% by the time you've reached the surface, may be enough to burst the lung. Also, some people have problem in equalising ears in the shallows. A burst ear drum could occur from surface to under the keel.

If you're going to get some training, why not do a basic scuba diving course?

I've never experienced hooka gear so it's wrong to give an opinion. Scuba, on the other hand, is not so difficult. There's a clue to its advantage in its name "self contained".

[steveallan]

[QUOTE=Ariadne;3352763]Buy your local diver a beer or two.


HI

Glad you made it to Gambia.

Local diver in Mamaris wants 50 beers (€250).

[ghostlymoron]

You will always need air under pressure. For every 10m of depth the pressure increases by 1bar. Therefore at 2m, the ambient pressure is 1.2bar. Your lungs just won't have enough suck to breath through a tube from the surface.

You may be correct in your conclusion but I don't think your physics is correct. At 2m depth, the absolute pressure will be 1.2 bar, however, the air pressure inside your supply pipe will still be 1bar. So the differential is only .2 bar which is what you will have to overcome.

[prv]

the differential is only .2 bar which is what you will have to overcome.

Yep - the error comes from mixing gauge pressure and absolute pressure.

Still, that's about 3 pounds per square inch. How many square inches is the surface of your chest, and are your intercostal muscles strong enough to lift that many pounds? I suspect not.

Pete

[savageseadog]

It's best to dive without smoking drugs

It's impossible to breathe atmospheric pressure air at a depth of 0.5m plus. Regarding embolism risk any air breathed in from any pressurised system at depth will be approximately at the ambient pressure regardless of the fact the air is free flowing or not. There is a quantifiable risk especially as breath holding is instinctive.

[electrosys]

If you're thinking of making your own system, the use of a two-hose mouthpiece (as used on the old honky-tonks - I loved those !) would allow excess air to escape behind you - one reason why some photographers prefer them. Ebay: #260941303223

Providing you stay above 30 feet there'll not be any problems with decompression etc. (assuming you're not diving in a lake at high altitude, or flying the next day), so if all goes pear-shaped, you can simply abandon the gear and go straight up to the surface - whistling as you go, of course.

Another approach would be to buy an out-of-date full-face-mask-respirator as used for firefighting aboard ships, and modify the 2nd stage regulator (built into the mask) for even lower pressure use. I bought a couple at a boot sale many years ago with this in mind, but never did get around to it. The regulator is made of brass etc, so would be suitable for use underwater.

[electrosys]

You may be correct in your conclusion but I don't think your physics is correct. At 2m depth, the absolute pressure will be 1.2 bar, however, the air pressure inside your supply pipe will still be 1bar. So the differential is only .2 bar which is what you will have to overcome.

I'm not sure exactly where measurements ought to be taken from, but someone snorkelling with their body vertical, with their head completely submerged - the bottom of their chest cavity would be some 2ft below the surface.
Now although 'body vertical' is an unusual position for snorkelling per se, it's a position scuba divers often present, with their weight belts and tanks etc - and breathing through a snorkel like that is no problem whatsover.

So - if 2 feet is manageable, would 6 feet (which should be enough to clear anyone's prop) ? Worth a swimming-bath experiment with a 'long' snorkel, I'd have thought.



Short while later ...

To answer my own question - Yes, 6 ft would be possible. I've just conducted a quick experiment, by standing on the deck of a boat on the hard, and sucking up water in a tube from ground level. 8 ft was no problem (at which point I ran out of tube), indicating that the lungs can tolerate a negative pressure of 8ft of water without difficulty.
Of course, with a 'long snorkel' you'd need to add a couple of flap valves to ensure you don't inhale your own exhaled breath, either that or discipline yourself to exhale through your nose or the side of your mouth.

[ghostlymoron]

I'm not sure exactly where measurements ought to be taken from, but someone snorkelling with their body vertical, with their head completely submerged - the bottom of their chest cavity would be some 2ft below the surface.
Now although 'body vertical' is an unusual position for snorkelling per se, it's a position scuba divers often present, with their weight belts and tanks etc - and breathing through a snorkel like that is no problem whatsover.

So - if 2 feet is manageable, would 6 feet (which should be enough to clear anyone's prop) ? Worth a swimming-bath experiment with a 'long' snorkel, I'd have thought.



Short while later ...

To answer my own question - Yes, 6 ft would be possible. I've just conducted a quick experiment, by standing on the deck of a boat on the hard, and sucking up water in a tube from ground level. 8 ft was no problem (at which point I ran out of tube), indicating that the lungs can tolerate a negative pressure of 8ft of water without difficulty.
Of course, with a 'long snorkel' you'd need to add a couple of flap valves to ensure you don't inhale your own exhaled breath, either that or discipline yourself to exhale through your nose or the side of your mouth.

So my idea is possible (for someone with reasonable lungs) and it could also be used on a boat with no electrical power and single handed.

[flipper]

So my idea is possible (for someone with reasonable lungs) and it could also be used on a boat with no electrical power and single handed.

I guarantee you will not be able to breath through a six foot snorkel. With a normal snorkel, try getting someone to push your head under the water until only the tip is out of the water - you can feel the lung squeeze.