Bookmark and Share Email this page Email Print this page Print

A hookah dive system

Oct 18, 2012
David Lynn put together a basic dive system using off-the-shelf parts.

David Lynn put together a basic dive system using off-the-shelf parts.

Alfred Wood/Ocean Navigator illustration

We had just arrived in the Galápagos Islands and were wending our way through all the cruising boats looking for a spot to drop the hook. I noticed a fishing float that appeared to be moving our way. Our prop had picked up a lost fishing line, and within seconds, the float disappeared under our boat. Fortunately, it didn’t stall the engine as it was only a minute or two before we found a place to drop the anchor and were able to safely cut the engine. As soon as we were settled in, I dove on the prop. We had several hundred feet of monofilament tightly wrapped and melted into place around the prop and shaft.

Luckily, there was a local dive shop close by and after renting a tank, I began sawing and cutting the line. One tank wasn’t nearly enough. It took four tanks, three dinghy rides ashore, and the better part of a day to remove the line. Had the dive tanks not been available, it would probably have taken days to clear the prop by free diving.

This adventure emphasized that it would be nice to have some sort of underwater breathing apparatus on board to handle emergencies. It would also make routine bottom and prop cleaning easier.

David Lynn

A quick disconnect fitting.

A few solutions came to mind. I could buy three or four dive tanks and keep at least a couple filled and ready. This would necessitate transporting dive tanks to the local dive shop in whatever port we were in, sometimes a challenge in more remote areas. I could buy a dive compressor, which would allow me to refill dive tanks aboard. Dive tank compressors were expensive, noisy and large, and required either a lot of electrical power or to be engine-driven. A third solution was to buy a hookah system with compressor. Unfortunately, commercial hookah systems are also expensive and large.

After doing a bit of research, however, I didn’t see why I couldn’t build my own hookah system. Essentially, I would need an air compressor, filter, 50 feet or so of hose, a dive regulator, and the necessary connections. While most of the commercial systems I saw were designed to provide enough air for two divers diving to a depth of 50 feet, my needs were much simpler. I would be using it alone, never in tandem. I would be working at a maximum depth of eight feet or so, while the usual working depth would typically be more like three to four feet. If anything went wrong, I could be at the surface with one kick, and I certainly wouldn’t be deep enough to need decompression stops on my way up. After a bit of trial and error, I was able to build one that has been working quite well for several years now.

The layout of the hookah is shown in accompanying schematic. The first step was to find and modify the regulator. I wasn’t sure that a standard dive regulator would work at the lower pressures of a hookah system. In a standard diving arrangement, the first stage regulator reduces the tank pressure to 150 psi, and the second stage regulator and demand valve is designed to work at this pressure. Most inexpensive compressors will provide less than 100 psi. There are low-pressure and variable regulators available at considerably more money, but I thought I could modify a standard regulator to work. I found several online for less than $100, but decided to buy a used one from a local dive shop for $35.

The heart of the system was the compressor. Obviously, the first requirement was that it must provide adequate air pressure, flow and volume. I wanted an electrically-driven, oil-less type, so there was no chance of breathing carbon monoxide or petroleum vapors. Also, it had to be small enough to stow aboard, and the power requirements should be low enough that I could power it from either my inverter or my portable 2-kW gasoline generator.

I wasn’t sure how to calculate how much air pressure, flow and volume was needed, so I cobbled the basic components together and did some trial and error with a few compressors I was able to borrow. What I found was that, at a minimum, I needed a compressor that would deliver at least two standard cubic feet per minute (SCFM) at 90 psi. As it turns out, this size compressor was commonly used for paint spraying, nail guns, etc., and was not only easy to find, but quite inexpensive as well. I also discovered that my newly purchased regulator worked just fine with this lower pressure and would not need modification. I purchased a compressor with an output of 2.6 SCFM at 90 psi and a six-gallon air tank. The tank allows the compressor to cycle on and off every few minutes rather than running continuously.

David Lynn

A filter for removing dirt particles.

I connected a standard pneumatic air filter and water trap to the compressor with quick disconnect fittings to prevent rust or dirt particles from being inhaled. It also filters out some of the moisture in the air, but I suspect this is less important. After all, I am breathing underwater with it and probably inhaling considerably more water vapor than the filter strips out.

The next step was selecting the hose. I looked at everything from inexpensive rubber pneumatic hose to mil-spec diving hose at several dollars a foot. I think if I was using this hose on a daily basis and diving to greater depths, I would be more inclined towards better hose, but for my application, a reinforced food-grade hose seemed the right compromise. I found 3/8-inch reinforced, food-grade air hose rated for 250 psi online for $0.40 per foot and purchased 50 feet. I used a brass barbed fitting adapter on each end and attached a brass pneumatic quick-disconnect fitting to the adapters.

To make the regulator easier to connect and disconnect to the hose, I cut off the end of the regulator hose and replaced it with a brass barbed fitting adapter and male pneumatic quick-disconnect fitting.

To use the system, I bring the portable gas generator and compressor on deck and make all the connections. For obvious reasons, I make sure the generator is downwind of the compressor. Then I flake out the hose into the water on the side I will be working. I use a Velcro strip to attach the hose to my upper arm, so that if I have problems or the hose becomes tangled, I can quickly detach myself by pulling the Velcro strip.

The next step is to start the generator and check the system for airflow and leaks. Then I climb into the water and get to work. Marcie keeps an eye on things topside to make sure my bubbles keep coming up and no problems arise. Before stowing everything, I give all the brass fittings a rinse in fresh water.

I have used the hookah system several times to clean the bottom, once to clear fishing line from the prop and twice to replace hull and prop anodes. It has performed flawlessly every time. One time, I loaded my portable gas generator and hookah system into the dinghy and spent six hours searching for a friend’s lost prop in a shallow anchorage off Opua, New Zealand. The depths ranged from six to eight feet, ideal for a hookah system. (Unfortunately the search was unsuccessful — it’s still buried in the mud there somewhere.)

Safety issues
Before you build your own hookah system, there are a few warnings:

1. I’ve never used the system at a depth greater than about 15 feet. I do not know if the described compressor/regulator combination will provide adequate air, or indeed work at all, at greater depths.

2. Even if the compressor and regulator do work in deeper water, I would definitely recommend having a backup system if using the home-brewed hookah system at any depths greater than you would feel comfortable free diving. If a fitting comes loose, the generator quits, the compressor stalls, or any number of other possible malfunctions occur, you will have to be able to swim back to the surface. As any diver knows, your ascent should be slow, no faster than 60 feet per minute, which could be difficult if a hose came loose and you have no backup system.

3. If you are working at depths greater than 30 to 40 feet for any length of time, you may need a decompression stop before surfacing. This would be impossible if there was a malfunction and you were dependent solely on the hookah system. The ideal backup system would be a separate dive tank and regulator.

4. Finally, there is no legal requirement to be a certified diver before using a hookah system, but the training received during a certification class is invaluable in keeping yourself safe when diving, whether using scuba gear or a homemade hookah.

----------
David Lynn and his wife Marcie live aboard their 45-foot 1986 Liberty cutter Nine of Cups.

Old to new | New to old
Nov 2, 2012 12:34 pm
 Posted by  Sea Bird

Very good information, thank you.

Is that any oil-less compressor? Could you send links to where you found the items to make up your hooka system?

Thanks,

Sea Bird...

Nov 2, 2012 04:59 pm
 Posted by  nineofcups

Hi Sea Bird,
You definitely want an oil-less type compressor for the reasons stated in the article. I purchased the compressor and fittings at a Home Depot. You can get the hose there as well, but I found it a bit cheaper online. I bought it from a seller on Ebay, but I no longer have the link.

I called a few local dive shops to find the used dive regulator. You might try Ebay or Craigs List if you strike out at the dive shops.

David

Dec 6, 2012 03:57 pm
 Posted by  diver jeff

As a professional dive instructor and dive equipment technician I was a bit alarmed at first when I started reading this article. The DIY attitude is admirable but I can foresee a couple of issues that while briefly addressed need more emphasis. First of all and foremost in importance is the possible skipping of training in using a home-made hookah system versus buying a system made for the purpose. While not nearly as complicated as learning to scuba dive using a hookah system in shallow water nonetheless has hazards not apparent to the novice. Breathing compressed air even at depths of 3 feet is hazardous. The #1 rule is NEVER EVER HOLD YOUR BREATH WHEN BREATHING COMPRESSED AIR. Holding your breath in as little as 3-4 feet with compressed air can lead to a very serious lung expansion injury (read extreme pain, pink foam coming out of your lungs, and possibly death) Not the sort of thing to deal with in a remote anchorage in a third world paradise.
The other issue I have is the so-called "oil-less" compressor. Oil less is not the same as oil free. If there is any sort of lubricant in the compressor it will find its way into the air stream. Breathing air compressors and even some of the hookah systems have filters designed for completely removing hydrocarbons from the air. Oil deposits in your lungs are not removable and you are stuck with reduced lung function for the rest of your life. Make sure the compressor is truly OIL FREE. In addition, the flow rate of the compressor is very important. If you are working hard swimming against a current or cutting away a mass of melted nylon fused to your prop and drive shaft you can use a lot more air than if you are just scrubbing slime off the bottom of the boat. Make sure the compressor has enough output for increased workload. Simply put, you are saving a few hundred dollars by DIY, is that worth your life or health?

Dec 7, 2012 03:32 am
 Posted by  nineofcups

Jeff has some valid points. I agree with his thoughts on the safety issues involved in using a hookah system. The article does point out many of the limitations and safety issues with a hookah system in general, and especially a homebrewed version. I also recommend taking a diver's certification course before using the hookah. Jeff's point regarding never holding your breath when breathing compressed air is well taken. It is a rule that every diver knows, but someone using a hookah with no prior training might not be aware of. This lends more support to getting some training before using a hookah system.

When I was doing my research on compressors, “oil-less” was a term that was used interchangeably with the term “oil free”. All the compressors I looked at were described as either oil-less/oil free or as oil lubricated. I agree with Jeff that an oil lubricated compressor should never be used for a hookah system, and this is what I intended to convey. If there is indeed an “oil-less” compressor that is lubricated with oil, then I apologize for the oversight.

I disagree with Jeff's final point. Firstly, the difference in price for a commercial hookah system is considerably more than a few hundred dollars. For me, it was a decision between doing it myself or doing without. Secondly, I consider myself a very conservative sailor. I would never knowingly put my crew, my boat or myself at risk. I understand the limitations and shortcomings of my DIY hookah system. I use it only as it was intended, I take the proper precautions, and I believe I convey that in my article. Simply put, I saved many hundreds, if not thousands of dollars, building a basic, limited hookah system that safely accomplishes what I need it to do.

Dec 8, 2012 07:56 am
 Posted by  diver jeff

I do not represent this company but the Keene Hydro Air electric hookah system runs on a 12v battery and sells for about a grand. I have seen lots of used systems on e-bay and other sources for as little as $800. It just seems to me that the professionally engineered systems will deliver better performance and service not to mention that they are designed for this use. For occasional use, small pony cylinder and scuba regulator could also be set up for a few hundred bucks too. It doesn't take up much space and is refillable at any dive center around the world. Scuba training, however, would need to be completed to be able to refill the cylinder.

Dec 25, 2012 04:13 am
 Posted by  Australis

David,

I really enjoyed your article. My company, SeaView Systems, Inc. in the US works with underwater robotics and we have a test tank in our workshop which we use to test out or various Remotely Operated Vehicles and other underwater tools. We have built up a system exactly the same as yours (The similarity is remarkable)and have been using it now on occasion for a couple of years. We only work in about 12ft of water max and the system has worked perfectly to date.

I also have a Liberty 458 and will be sure to build this system into the yacht for the same purpose that you have identified.

Regards,

Matthew Cook

Jul 31, 2013 08:05 am
 Posted by  Kent

I was thinking of building a system like this for my boat as well...thanks for your timely article! I was considering making it capable of going down 25-35 ft to allow me to retrieve a fouled anchor as well as the hull and prop issues. My boat is European and has 24v DC and 220v AC systems. Anyone have any suggestions about pump/compressor size? I'd prefer an electrical system as I have a genset on the boat and don't want another gasoline engine aboard. I am certified in scuba but feel the size and hassle of storing and filling tanks is prohibitive.
Thanks for any thoughts.
Kent Robertson
S/V KRISTY 53' Amel
Currently Brunswick, GA, USA

Add your comment: