Ultra sound anti foul devices

[Rustic Charm]

Does anyone have any credible and recent updates on how these electronic anti foul systems work now days?

I'm surprised there has not been a dedicated thread on this available via the search window.

Does anyone have any real life experiences with them?

https://www.cleanahull.com.au/

[transmitterdan]

There are a few reports I have read. The reports I read that seemed independent indicate they don't work in general. I think you will hear less and less about these as time goes by.

Intuitively I have to think these things cannot do what they claim. They vibrate the hull at a very localized spot and somehow (magic?) that is supposed to propagate over the entire hull to prevent attachment by critters. Hull types vary so much and ultrasonic waves are attenuated massively by fiberglass especially if cored with foam or balsa. Even if it worked right where the ultrasonic vibrator is mounted I can't see it doing much a few feet away from that point.

[Dockhead]

PBO has done a few tests of these systems. If you google around a bit, you might be able to find them posted somewhere.

I seem to recall that one test a few years ago came out pretty well, but a recent one (January?) not so good.

[Emerald Sea]

I put a set of US system (Clean-a-Boat, Australia) on my previous 40ft boat based in the marine growth aggressive tropical waters of Singapore and it ran 24/7. There were two transponders and it was on for 2 years before I sold the boat. Easy to install. I'd say it was 95% effective with the occasional barnacle getting a foothold. Doesn't work around the water line of course.

[Chuck Hawley]

Ultrasonic antifouling has been around for a long time; I remember seeing a "Cricket" system installed in someone's boat perhaps 30 years ago. My recollection is that while they might have some benefit on hard growth, they had virtually no effect on soft growth.

Chuck

[fstbttms]

If ultrasonic systems performed as advertised, we'd see them everywhere. But I have been in the hull cleaning biz for over 20 years and have yet to come across a boat with one installed. That speaks volumes, IMHO.

[crazyoldboatguy]

I have done lot of reading on the subject of anti-fouling while researching the various ways to protect a wood hull from the sea critters that abound. I got real excited about the US stuff when I first read it, until I found they wouldn't work with a wood hull - much like how a depth sounder won't work with a sound head inside the hull. If I was sticking in one spot, maybe the pier mounted system would be more effective but, as fstbttms says, if it worked as well as the ad copy, we'd see a lot more of them around.

I'd also be concerned about the electrical draw and the fact that with 2 of them (boats over 40' will "need" 2, per the ads) you are adding that much more complexity to your electrical systems. If one fails and you aren't near a haul out - now what?

[Sun and Moon]

Originally Posted by fstbttms

If ultrasonic systems performed as advertised, we'd see them everywhere. But I have been in the hull cleaning biz for over 20 years and have yet to come across a boat with one installed. That speaks volumes, IMHO.

I'm a big fan of fstbttms, but I might draw the opposite conclusion here. If they didn't work, their owners would have to resort to traditional cleaning methods. Since he's cleaned a lot of boats and never seen one, perhaps they do work after all and those boats don't need cleaning.

Goes to show, you don't ever know...

[mikereed100]

Originally Posted by Sun and Moon

I'm a big fan of fstbttms, but I might draw the opposite conclusion here. If they didn't work, their owners would have to resort to traditional cleaning methods. Since he's cleaned a lot of boats and never seen one, perhaps they do work after all and those boats don't need cleaning.

Goes to show, you don't ever know...

From what I understand of these systems, they don't eliminate the need for bottom maintenance, just theoretically extend the useful life of the paint, allowing for fewer haulouts.

[fstbttms]

Originally Posted by Sun and Moon

I'm a big fan of fstbttms, but I might draw the opposite conclusion here. If they didn't work, their owners would have to resort to traditional cleaning methods. Since he's cleaned a lot of boats and never seen one, perhaps they do work after all and those boats don't need cleaning.

Goes to show, you don't ever know...

While I appreciate the kind words, I have to disagree with you. I have performed over 25,000 in-water hull cleanings on many hundreds of different boats here in the Bay Area. Further, the hull cleaning business community is not a particularly large one and I have contact with many hull cleaners up and down the coast. Out of all that, I have only ever heard of two boats that have had these systems installed. Both were J/120s, both actively raced out of San Francisco and in both cases, the owners were dissassisfied with the performance and stopped using them. If ultrasonic systems were being used with success here (or anywhere in California, to be honest), I guarantee I'd know about it. It would not be a secret.

[transmitterdan]

Intuitively you have to wonder how these things can work. People imagine the ocean is silent but I can tell you from experience it is very noisy. I doubt a little more noise will convince critters that have almost no nervous system to live somewhere else. Also, when you think about the huge variation in hull construction and the dampening properties of materials immersed in water it is inconceivable that a one size fits all gadget can accomplish what is claimed. The whole thing just doesn't pass the engineering "smell test".

I know some have given a positive anecdotal report. Many more reports are not that promising. But what would help convince the doubters like me is some independent studies that clearly show a huge improvement over quality paint. So far I can't find even one.

[fstbttms]

What I need to see is a side-by-side comparison test- Two similar boats, berthed in the same place (in a region of high fouling) using the same anti fouling paint. One boat is equipped with the ultrasonic system, the other is not. Regular in-water inspections of both with pix or video (say, monthly) for a year. If the ultrasonic boat showed markedly less fouling than the control boat, then I could buy into the concept. Unfortunately, none of the system's makers seem inclined to do this. I wonder why?

[Huskybeer]

You need more than 2 transducers. You need to have a very good hull paint with a very good anti fouling layer, otherwise it will not work so well. Furthermore if you put SeaSlide as last layer you have max effect and a little longer lifetime of your antifoul paint

[cwyckham]

I'm concerned about the effect on marine mammals, even if they do work. The frequency of the one that I looked into was right in middle of the typical dolphin echo-location frequency band.

Bowriding dolphins are worth hauling the boat more often.

[mikereed100]

Originally Posted by fstbttms

What I need to see is a side-by-side comparison test- Two similar boats, berthed in the same place (in a region of high fouling) using the same anti fouling paint. One boat is equipped with the ultrasonic system, the other is not. Regular in-water inspections of both with pix or video (say, monthly) for a year. If the ultrasonic boat showed markedly less fouling than the control boat, then I could buy into the concept. Unfortunately, none of the system's makers seem inclined to do this. I wonder why?

Or, they have done these comparisons and did not like the results so chose not to make them public. I hate to be a cynic, but drug companies do this all the time.