Ultrasonic antifouling

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Here's a thread from a while back. "fastbttms" is a hull diver and will likely chime in with some of his usual FUD. Seems he lives to post on ultrasonic systems.

I reached out to HullShield and asked for a "twin study" where one hull of a catamaran has their system, the other does not. They said it was in the works but that was about 2 years ago. Nothing so far, just a lot of anecdotal claims. Until something more definitive comes along, I categorize it alongside Algae-X fuel magnets.

https://www.trawlerforum.com/forums/showthread.php?t=47771

Reading through the above thread, sounds like Syjos installed the system. Maybe he'll update on performance.

Peter

The one thing that seems most apparent to me is the lack of a side by side study in a catamaran. If I owned the company, you can be damn sure we would have tried that because that would have been the best marketing tool possible for my product if effective. I can't imagine this has not been tried. My assumption is the results are less than impressive so the effort to continue to promote sales can only be anecdotal.
 
Ted, I probably should have included a photo in the video. The bow thruster emitter is epoxied to the thruster mounting frame (see photo). I figured this is all one solid mass that the sound wave would travel through but maybe that’s not the case. The hydraulic fluid and gear oil may be absorbing some of the sound waves. I could add an emitter on the 12” tube on each side of the thruster but not sure if that would help as the barnacles are on the thruster prop.

If it were me, I would remove it from where it is. I would sand the gellcote off the tunnel in a small area and build the fiberglass up until you can sand a flat spot to mount the transducer on. To me, the transducer should work better as the tube is thinner than the hull.

Ted
 
If it were me, I would remove it from where it is. I would sand the gellcote off the tunnel in a small area and build the fiberglass up until you can sand a flat spot to mount the transducer on. To me, the transducer should work better as the tube is thinner than the hull.

Ted

As I understand the technology I don’t think sound waves on the tunnel will impact the prop. I’ve sent an email to their support to get their feedback. Easy enough to move the emitter to the tunnel if they will help.
 
Skimming that video, I don't see anything new. Some guy paid big bucks for a product, and really wants to believe it works. Just like the JD Powers "new car buyer survey" results. People don't say "yeah, I made a stupid decision, that car is junk" just days after purchase.

I'm still waiting for a controlled, double-blind, unbiased, peer-reviewed study.

I really would love to believe it was this easy to prevent fouling. We'd all benefit, as would the environment. Word would spread, and everyone would be using it. The inventor would be rich. When I see that happening, I'm in!
 
Skimming that video, I don't see anything new. Some guy paid big bucks for a product, and really wants to believe it works. Just like the JD Powers "new car buyer survey" results. People don't say "yeah, I made a stupid decision, that car is junk" just days after purchase.

I'm still waiting for a controlled, double-blind, unbiased, peer-reviewed study.

I really would love to believe it was this easy to prevent fouling. We'd all benefit, as would the environment. Word would spread, and everyone would be using it. The inventor would be rich. When I see that happening, I'm in!

Just sharing my experience. The cost was chump change in the grand scheme of things so I can write off with no ill feelings. 5 months in and short of some algae at the waterline and a few sporadic barnacles not much else to report. All I can compare to is my last haul out/bottom job where at 5 months I had significant barnacle growth.
 
Helllo guys,
in the moment I don´t have my own boat, but I´m busy with plans, architect and shipyard. One of the points I focused is the antifouling and the options to make this on a cost efficient way without need to slip the boat every few months and refresh the antifouling. But I guess the ultrasonic system is a fraud. The history of this system is based on the experiences from the submarines times at WW2. They find out that around all the sonar sensors was not so much fouling than around the complete hull of the submarine. Later few companies gone that way and build some supersonic antifouling. The funny thing is that every company explained the working of there system on different ways. So they have had no idea how it really works. The German federal environment department (Bundesumweltamt) published last year a study about supersonic antifouling systems.
You can read here:
"The use and benefits of ultrasound systems as an anti-fouling technology are still controversial. Even among the companies that offer these systems, the way they work is inconsistent. Some companies explain that they work by generating cavitation, while other providers want to avoid this because cavitation could cause damage to the hull. There are currently around 10 providers of ultrasound systems on the German and European market. A precise description of how they work, the frequencies used, energy, etc. is usually not provided.
It is now known that the cleaning effect of ultrasound systems is based on the induction of cavitation. The effect is achieved by generating microbubbles that are created when a sufficiently high, negative pressure is exerted on a liquid. Compression and decompression waves pass through the liquid very quickly. If the waves are strong enough, they can break the attractive forces in the existing molecules and create gas bubbles. When ultrasound energy flows through a liquid, the gas bubbles generated grow to a certain critical size, at which point they collapse and implode. The resulting shock energy generates the sono-chemical reactions. According to the "hot-spot theory", the collapse of the gas bubbles produces a rapid and extreme increase in temperature up to 4000 C° and a high increase in pressure, both of which cause the generation of free radicals with strong oxidative properties. Thus, at low frequencies, the physical phenomena are said to predominate, and at high frequencies, the chemical phenomena."

They tested with 4 different boats.
Hallberg Rassy 38
sailboat Hanse 350, build up 2007
saailboat Sun Odyssey 409
sailboat Hanse 445

All boats was in private use and they was protected with different antifouling coat. The result was in all cases that the ultrasonic system was not very good working. It was more easy to clean the boat hull with high pressure water later than it without the ultrasonic system. But the hull was almost covered with seagrass, vegetation, shellfish and barnacles like it was with paint only. Nobody from the 4 boat owners wanna hold the systems.
Here the German language link to this study:

Other studies I found show that there is an effect, but you can´t protect a complete boat hull. It´s not useless, but it's not good working.
 
Might work better on a metal hull. Wonder if tests show that. Would still have issues with running gear I would think
 
Thank you, it's always good to see real-world results (or lack thereof.) Obviously I don't know all the specifics from your brief summary, but the conclusions are about what we all would expect.
 
My dockmate here on Vancouver Island has a Tolly 36 and recently installed an ultrasonic system which claims to inhibit underwater growth on the hull by introducing a series of ultrasonic vibration pulses into the hull 24/7. A couple of 'pucks' are glued to the inside of the hull and wired into a central 12v sending unit.

It claims to disrupt growth at the cellular level by basically 'shaking' the little critters so they can't settle in.

The makers are very clear this will not remove existing growth and will not work if it is installed on an already overgrown hull. It has to be a clean start.

My neighbour pulled the boat out almost a year ago for cleaning and fresh paint and installing the units. So far it seems to be working really well - nothing growing.

Current price is around US$1700 for 4 pucks and processor. Fairly easy DIY install. Not cheap, but if it allows him to go from an annual haulout to every second year, it wouldn't take long to pay for itself.

I can't find any previous mention of this on the Forum. Anyone tried it?
I tried and don’t work as well, the two that I installed close the props, doesn’t work
 
My dockmate here on Vancouver Island has a Tolly 36 and recently installed an ultrasonic system which claims to inhibit underwater growth on the hull by introducing a series of ultrasonic vibration pulses into the hull 24/7. A couple of 'pucks' are glued to the inside of the hull and wired into a central 12v sending unit.

It claims to disrupt growth at the cellular level by basically 'shaking' the little critters so they can't settle in.

The makers are very clear this will not remove existing growth and will not work if it is installed on an already overgrown hull. It has to be a clean start.

My neighbour pulled the boat out almost a year ago for cleaning and fresh paint and installing the units. So far it seems to be working really well - nothing growing.

Current price is around US$1700 for 4 pucks and processor. Fairly easy DIY install. Not cheap, but if it allows him to go from an annual haulout to every second year, it wouldn't take long to pay for itself.

I can't find any previous mention of this on the Forum. Anyone tried it?
Nearly a year since original post. By now a diver or haul out would show the results. Have you asked your friend?
 
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