Surface Air Supply (Hookah) Systems

[Jammer]

Originally Posted by Ninedotsix

The industry safety standard in USA is for “Grade D breathing air”, and you can get plenty info on that if interested.

Actually for underwater use the standard is Grade E which is somewhat stricter than the Grade D air used for industrial/fire SCBA. The hyperbaric underwater environment makes many contaminants more toxic and the Grade E standard reflects that.

[Jammer]

Originally Posted by captlloyd

Very true, those depths [30'-40'] are starting to be in a zone a person needs to think about nitrogen buildup when staying for more than a few minutes. Consult the dive tables for nitrogen buildup, the cause of bends.

I know you mean well but that simply isn't true.


According to the PADI recreational dive planner, a widely used, conservative dive table, it is safe to dive for up to 205 minutes at 35 feet or 140 minutes at 40 feet. The IANTD tables set the no-decompression limit at 125 minutes at 40 feet and do not specify a time at 35 feet.


But in any case, anyone diving to these depths -- whether on SCUBA, hookah, or freediving -- should receive in-person training from a recognized program. Dive training is inexpensive and widely available.

[alanfw]

Thankyou everyone for the interesting discussion. All the dive theory relating to depth, pressure, gas solubility is pretty much the sort of stuff I taught senior Physics students before I retired. What I DON'T know is specifics on compressors and typical air usage rates. The discussion has been helpful here. In the end, I gave up on the "cheap" DIY hookah - I'm sure I could do it, and probably do it well, but I'm a little reluctant to experiment with my life - so I bought a not-so-cheap "Porta-hookah" (https://www.hookahdivingsystems.com/) which should be arriving in a week or so. It seems like a well-designed piece of kit, with appropriate power supply, compressor, filtration and cooling. Then it's into the swimming pool at home to get familiar with it before taking it to the boat.
Cheers
Alan

[captstu]

Do you do anything to test for stray electrical currents when you dive in a marina?

[IMWA]

Have a look up for Hookamax from USA. I used one for a long time without issue - not the cheapest but provides medical grade air.

[rslifkin]

Originally Posted by captstu

Do you do anything to test for stray electrical currents when you dive in a marina?

In salt water, it's generally not a big concern. I'm sure the pro divers here can confirm though. In fresh water where I am, the general wisdom is that if you're around boats plugged into shore power, you don't get in the water for any reason.

[MicHughV]

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Some years back, I went diving with a guy that had one of these. It could take care of two divers. I don't recall how long the hoses were....50'....75'...something like that.

I didn't like it though, no-one is minding the little gas fed engine, if the sea surface gets rough, that thing starts really bobbing around.

We have a guy at the marina that scrubs boat bottoms for a side job. He uses a 100cf tank, which he leaves on the dock on a small wheeled carrier. He has about a 50' hose with it. I've seen him clean several boats in a row without any problems. When he is cleaning the water line, he just uses a snorkel.

I think that is the way to go...simple...inexpensive...safe...

[skipperguy]

Originally Posted by alanfw

I've been looking at options to allow me to go below the boat for cleaning and maintenance.
The cheapest I've come across is this:
https://www.ebay.com.au/itm/15475752...wAAOSw2XZhv9aK
It appears to just use a simple high flow rate aquarium air pump, so low pressure (negligible depth). I worry the pump isn't up to the task. It also seems expensive given the pump used.

Another option is this:
https://www.ebay.com.au/itm/37382899...0AAOSweaFhsfOr
Three times the price but looks safer and more flexible.

The final option is using a 12v compressor like this one and buying hose and stage 2 regulator from eBay, and probably a filter too.
https://bossairsuspension.com.au/sho...flation-combo/
(I did see another compressor tank combo that looked better but now I can't find it).

I'd like to hear opinions from people with more experience than me - that is, any experience at all!

PS: I already have a 54AH lithium battery I use to power my electric outboard, so that means the electricity supply is already sorted.

"engineer's" answer. at your required depth i would think 2 tubes of sufficient diameter (2" ???) with a flip-flop valve would do

[carambo46]

https://gatorgillllc.com/
I got my rig there good prices good people

[CyKlop]

Master Scuba Diver Trainer (Padi, MSDT-66410) and IANTD Nitrox blender...

1. For the depths being discussed (bottom cleaning, prop changes) I'm not worried about nitrogen buildup problems. The No Decompression Limit at 33 feet/10 meters is in excess of 5 hours. It's a LOT longer at 4-5 feet/1 - 1.5 meters Even my racing-keeled boat has a maximum depth of 9 feet. Add, say, 3 more feet because I'm "below" my keel and that's still only 12 feet/3-4 meters.
2. The bigger worry would be barotrauma (as another poster stated) aka "lung expansion injury" due to a panicked ascent if something goes wrong (mask floods, air supply cut off, mermaid attack, etc.). Ambient pressure at 9 feet is 1.27 ata. So if you take a nearly full breath at depth, hold your breath, and ascend to the surface, your lungs are suddenly at nearly 125% of capacity. They don't like that very much and may kill you for that abuse faster than a spouse will kill you for consorting with mermaids/men. Training will give you experience with these sorts of things and thoroughly (if a good instructor) inculcate you with NEVER STOP BREATHING. BREATHOLDING = BAD (when breathing compressed air).
3. Breathing contaminated air is very very bad. Amounts of petrochemicals on your air that are merely distasteful at sea level become highly toxic under water. How toxic? Depends on concentration and pressure. So just don't fool with that. Further, the contamination doesn't have to come from the compressor itself. Nearby running engines, for example, if the wind carries the exhaust to the compressor, can contaminate your air through no fault of compressor maintenance.
4. Do you have the knowledge, time, and fastidiousness to maintain the compressor properly? The hoses? The regulators? The filters? __WILL__ you maintain them? Salt water air is an intensely corrosive/destructive environment in which to maintain mechanical components. Besides just failure of the engine, there is potential failure of all the pressure vessels, fittings, hoses. Even 100 PSI can be a potential "bomb". Admittedly, we're dealing with 3000 PSI+ pressures rather than 100 PSI, but there's a REASON we fill tanks in a water jacket (besides keeping them from being a "hot fill"), have tanks visually inspected every year and hydrostatically tested every 5, have the compressor on a strict inspection and maintenance schedule, and test the output by sending samples to a commercial lab on a frequent basis (and after every maintenance).

I'm not trying to tell you NOT to do this. I'm merely setting out SOME of the things you need to think about and answer honestly before even considering this endeavour.


There are people (and business/organizations) that do not adhere to some of the above thoughts, but that's just _some_ of the things that a conscientious, safety-standard aware/compliant gas handlers will deal with.

[eagleman]

This works very well for bottom cleaning, prop work, etc...VERY reasonably priced and COMPACT.

Home Depot: https://www.homedepot.com/p/RYOBI-ON...P739/305269932

Harbor Freight: https://www.harborfreight.com/38-in-...ubber+air+hose

Amazon: https://www.amazon.com/Hanperal-Expl...s%2C90&sr=8-21

Amazon: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[RickG]

We liveaboard on a mooring. A hookah setup takes up more room than I would like. I went with a used BC and octopus from our local dive shop. Air costs me $7 per cleaning. I like the idea of a hookah, but not the cost or storage.

Cheers, RickG

[ScottinMA]

Another option: https://divingsnorba.com/s/

[sailian89]

Frankly has your answer. Stopped reading there!

[garychurch]

Get a scuba tank tank or two and have them filled at a dive shop.

An 80 cu ft tank will last an hour or two used in conjunction with a hookah and regulator.

Don’t use a Rube Goldberg setup and put your health at risk.