Water blasting barnacles below waterline while diving?

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Keysdisease said:
I'm in South Florida so we have significant hard and soft growth here.

I used a 15* standard tip. Anything wider for me just wasn't effective.



:socool:
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What psi did you use with 15 degree nozzle.

I suppose, one needs to learn the right distance from the surface, so the paint would not be damaged, but still knocking off the growth?
 
Regarding the thrust of the nozzle, it will be less than it is in the air. You want to think of it as having the water to push against underwater, but that is not the physics of jet propulsion. Thrust is greatest into a vacuum, and less into anything else, lower with increasing depth.
 
LeoKa said:
Agreed. As I said earlier, a bottom job is coming up next year. It should sure help my situation. For now, monthly diving is what I can do.
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Did I miss the reason you don't go ahead and do the bottom now?. Yards typically have more space this time
of year.
Hollywood
 
hollywood8118 said:
Did I miss the reason you don't go ahead and do the bottom now?. Yards typically have more space this time

of year.

Hollywood
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The yard I used last time has space, as long I reserve it two months ahead. Here in the PNW the winter is quite rainy. Not good for hull painting, unless you cover everything up.
Spring is my aim for this, as long the budget permits it.
 
DDW said:
Regarding the thrust of the nozzle, it will be less than it is in the air. You want to think of it as having the water to push against underwater, but that is not the physics of jet propulsion. Thrust is greatest into a vacuum, and less into anything else, lower with increasing depth.
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Thanks. I suspect I will need to test and try different nozzles and distances from the hull surface. I am not expecting perfection, but any tool which can help to reduce the physical load, is welcome.
At age 70 things do not work as good, lol.
 
North of you they are everywhere. Don't know of any south of Cape Caution.
 
Tidal grids have been phased out in our area due to environmental concerns. A shame really, as they were so convenient for quick trips like cleaning props and whatnot. Now they’re hazmat sites.
Growing up in SE Alaska, they were all we had. One tide to scrape and clean, one more to paint. Still remember the smell of the place.
I would imagine if there’s any grids available you would have to contain everything and dispose of it upland.
 
Larry M said:
One dive company that cleans boat bottoms in our marina use a gas powered pressure washier for props, rudders and shafts. It’s a better and quicker job than doing it manually. It is a little unsettling when your inside and hear the underwater noise though. They still scrape the bottoms.
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Same here. My divers use a very large (think industrial size) 4300 psi washer with a short (2’) gun and a wobbler jet nozzle. Great for tight areas, running gear & thruster tunnels apparently. These pro salvage divers tell me they have to fin hard to stay in place, not for the faint of heart. They also try to minimize its use ‘cus it’s very hard on the paint, for which I thank them & tip accordingly.
 
What about the cloud?

It you did a water blaster in California - huge fine!!!

No water clouding!! So no to a ablative bottom for sure!
 
RT Firefly said:
Greetings,
Mr. L. I would certainly try a pressure washer and I'm sure you can get a cheap wand that can be adapted to a short profile. The ONE concern I would have is reverse thrust. Exit of water under pressure will want to push you in the opposite direction unless you can anchor yourself, somehow (stand on the seabed?, grab rope?, waterproof skyhook?).
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I had the exact same thought... Great minds?!
 
LeoKa said:
I do my hull cleaning with a hookah setup. It is not bad, but I get tired fast.
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Something to bear in mind is that when you exhale, not all your breath escapes into the atmosphere - some is left in the pipe. When you next breathe in, you will inhale some of your previous breath which will have an increased level of CO2 in it. This increases, breath by breath. Not surprised you feel tired, quickly.
 
greatpapabear said:
Something to bear in mind is that when you exhale, not all your breath escapes into the atmosphere - some is left in the pipe. When you next breathe in, you will inhale some of your previous breath which will have an increased level of CO2 in it. This increases, breath by breath. Not surprised you feel tired, quickly.
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I thought it was my age.
What is the solution?
 
greatpapabear said:
Something to bear in mind is that when you exhale, not all your breath escapes into the atmosphere - some is left in the pipe. When you next breathe in, you will inhale some of your previous breath which will have an increased level of CO2 in it. This increases, breath by breath. Not surprised you feel tired, quickly.
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I believe your thinking about a snorkel, a hooka uses a dive regulator and the exhaust is not re breathed.
Hollywood
 
hollywood8118 said:
I believe your thinking about a snorkel, a hooka uses a dive regulator and the exhaust is not re breathed.
Hollywood
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Correct. I have an air compressor with air filter and 100’ hose with a second stage regulator at the end. I don’t there is any re-breathing going on.
It must be my age.
 
SteveK said:
yup, getting tired faster as we age. next you will start having afternoon naps.
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I already have those…. Don’t tell me that I am getting old.
 
Last edited:
Something I saw in California many years ago was a heavy plastic liner in slips for racing sailboats. A board at the end of the slip, stretching between walkways, holds the back of the liner up when docked and is weighted to sink and allow the boat to leave. Once docked the board is pulled up and the water around the boat is isolated from all other water. A half gallon of bleach is added around the boat and nothing grows. Probably illegal now.
If my private dock was in salt water, I'd do it here.
 
underwater hydro blast cleaning

A few years ago, I was involved with an underwater blast cleaning operation.
They were removing a concrete coating from an undersea pipeline. Depth 60ft.
The jetting guns were very specialised so as to neutralise the jet reaction. Basically had an equal and opposite discharge tube. The back tube was about 3.5 feet long so that the diver could not injure himself. Indeed a tube broke off, and the diver removed his bicep.
As previously noted, not so much a problem if one can anchor your body securely. I think the jet reaction would be significant even with moderate operating pressures.
 
Have you thought about using an ultrasonic anti-fouling system like sonihuall or hullshield? Install once and never have to drive and scrape again.... will likely pay for itself in one season. The USCG uses the technology on most of their smaller vessels.
 
kchace said:
I'll second RT's comment. If you're having trouble staying near the hull now, think of the thrust of a pressure washer pushing you away much more than hand pressure. You'd need a plan (something to hang on to?) to counteract that thrust.



Ken
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That was my first thought. You'd be like Rocket J Squirrel down there.
 
captkev said:
Have you thought about using an ultrasonic anti-fouling system like sonihuall or hullshield? Install once and never have to drive and scrape again.... will likely pay for itself in one season. The USCG uses the technology on most of their smaller vessels.
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I keep waiting for one of these systems to use a catamaran to demonstrate effectiveness of their product. One hull with, one without. Until then, I will put their marketing material in the same file as Algae-X magnetic fuel cleaners.

Peter
 
captkev said:
Have you thought about using an ultrasonic anti-fouling system like sonihuall or hullshield? Install once and never have to drive and scrape again.... will likely pay for itself in one season. The USCG uses the technology on most of their smaller vessels.
Click to expand...



My hull is steel. I’ll look it up, if steel surface is a problem?
I know one boat here in the marina who has it and it works for him. He has a fiberglass boat.
 
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