Diving Without Tanks - Surfacedive/Supersnorkel???

[Buck2796]

Fred, Chris, and Rob,

First, I'm a certified diver (advanced open water and nitrox) and have been (recreationally)diving now for almost 20 yrears. I agree w/ all the posting re. hazards, safty, etc.When I commissioned my 420, I did exactly what you suggest, Fred,... I installed an oiless (paint-type) compressor under the salon setee, and wired it into the AC panel. It does draw too many amps at startup for the invertor to handle it, so I run my genset to power it while at anchorage.In addition to using the compressor to blow up the RIB and other uses, I attached it's output to a small (paint sprayer type) regulator and use 50' of hose to a scuba second stage regulater/mouthpiece. For the past 3 years I/ve been using the rig to dive under the boat , cleaning the bottom, changing zincs, etc. I do have a second person on deck while I'm diving, just monitering the compressor, but on the rare occasion that the breaker has tripped off while I've beeen underwater, the air tanks, that are an integral part of the compressor unit, hold enough air that I can easily make a safe accent when I sense the air is gettting hard to "suck" (as with an scuba air tank when its getting close to being empty).The unit has been working great for me and is far easier and more convienent to use than tanks for this type of work.I do have an additional section of hose that can be added if I were to need to dislodge a stuck anchor or dive to the bottom to recover something, but to date have not needed to use it.

 

[txsailor]

A question for Buck

I have often thought that a simple system such as yours would work. I am also a certified diver... over the years taken many several other courses and worked upto divemaster. What pressures do you set the regulators at the tank and secondary regulators to feed the second stage regulator. And what size compressor did you purchase, as well as any other thoughts you would like to pass along to someone who was going to build their own system. Thanks Don

 

[Chris Burti]

Buck

When I started diving, the compressors widely in use at the time were not oil-less and required elaborate, high-maintenance filtration to produce usable air. They either ran off of small gas or diesel engines or off of a PTO from the main engine. Wind direction relative to exhaust was a concern. These were most often mounted in a filthy, cluttered dredges, barges and workboats and you can well imagine the hazards.In the early 70's I had a recreational hookah marketed by OMC (it used the same 2-cycle engine as the Lawn-Boy lawn mowers). It floated in an innertube, used unregulated full-face masks with check valves, had two 25' (garden..tic) hoses and a snorkle for the exhaust (kinda bass-ackwards as CO is heavier than air).I suspect that the rig you are using is far, far safer and more reliable than the ones I logged so many hours on and makes perfect sense to me. Tanks have their own hazards, and for shallow water work, I'd prefer your rig.The main point I was trying to make is that using this equipment isn't as simple as it might seem, that the hazards are both serious and likely to occur.

 

[Buck2796]

Don and Chris,

I purchased a standard (paint-type)compressor unit from Costco for less than $300.00... can't remember the exact CF/min output, but calculated that it would be adiquate to provide enough air for diving before making the purchase. Its output is approx. 100-120 psi.The unit came w/ compressor and tanks mounted to a frame. I had to cut the frame and separate tanks from compressor to get them both into the space under the setee; then reconnect them with a copper air line. I than purchased a small regulator from Home Depot normally used to regulate air pressure for painting jobs, at a cost of less than $30.00. I use it to reduce the line pressure to the second stage to about 80psi, which seems to work comfortably to provide enough, but not too much (doesn't "free-flow"), air, underwater.Including hoses, quick disconnect and other fittings, etc. total cost was about $400.00, not including an old Sherwood scuba second stage (which I already had).If you need help, find any mechanic type guy with air compressor experience. Its not a hard job. I am told that these types of oiless compressors, when used in a marine environment, may not last more than 5 years or so. Mine is working just fine after about 3 and a half years. But the cost is such that even if its necessary to replace it in a couple of years, that ok...And Chris, I, too, have dived w/ a gas powered "Hooker" type rig... I didn't like the exhaust air that we were breathing either. This oiless, electric, compressor setup provides nice clean, "no problem" air. And its inexpensive and easy to use....Oh, when I'm under the boat, not only can I hear the genset running, but I can also hear the compressor cycling on and off. It's a warm fuzzy feeling to hear it making the air you're breathing, and on the 1 or 2 occasions when the breaker tripped (maybe because the compressor over heated????), I knew something was wrong and came up as it began to get harder to "suck" air......

 

[p323ms]

Always be able to free ascend!!!

When I learned to scuba we had to do a free ascend from 80'. My instructor told me to take the regulator out of my mouth and hold it in my hand. Then he and I ascended to the surface. They don't train this way now because it is a little dangerous. But it really improved my confidence!!!! The long snorkle idea is really bad. I almost died that way when about 10 years old. At the swimming pool there was a garden hose and I had the "bright" idea to go to the bottom and breath through the hose. Collapsed my lungs the second I tried to breath. Fortunately I was unhurt. 10 year old's aren't known for their knowledge of physics. My son asked me about the same thing when he was about the same age. Fortunately he did not have to learn the hard way. Buck's system with a tank and compressor sounds good. As the tank emptys it should give some time to get to the surface. There was a nightmare scenario up at Kentucky lake several years ago. They harvest shells using hooka rigs. A diver had accidentally over inflated his dry dive suit and couldn't release himself to go to the surface. He apparently was trapped in that state for a couple of hours until his compressor ran out of fuel!!!! My wife and I were at the Paris Landing State Park docks when they brought in the body. They had lost another diver in a simular way when he got wrapped in a fishing net and couldn't free himself. After seeing/hearing about this diver I changed my mind about a dry suit. Some have pressure release valves at the ankles that might be safer. But if it's too cold for my wetsuit I'll just wait till spring. With who knows what under the docks at a marina and the possibility of stray electric currents that can paralyse there isn't a much more dangerous place to dive. But to each his own, I've went into downed trees to spear catfish. Wrestling a 10 # cat in zero visability in a tree while 30' underwater probably isn't as safe as sailing.

 

[Herb Parsons]

With all due respect

I've been a certified diver since 1979, and there is no way I'd take one breath on land, let alone underwater, from a home-made rig like the one described. This is LIFE SUPPORT equipment, pick out your equipment like your life depends on it being reliable, it does.