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Old 02-19-2013, 07:25 PM   #21
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I agree that the case has not been proven, I guess it's a case that is difficult to prove as there are so many variables that cannot be controlled or checked.

If it was a regular anti fouling coat then it could easily be tested by intentionally leaving out a patch (not coating a small area)and then compare it to the coated area. But this is not possible with the ultrasound systems since they cannot be restricted to some areas only.

Well - thinking about it - it can be tested by installing the system on a catamaran type boat where the system is only installed on one of the pontoons.

I don't believe in the Alge theory either, but the theory behind the ultrasound makes sense to me.
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Old 02-19-2013, 08:00 PM   #22
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Capn Chuck,

Only took me about a minute to pop over there and search "Ultrasonic Antifouling" and the 2 threads I referred to showed up.

I think they covered everything imaginable.
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Old 02-19-2013, 09:46 PM   #23
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RTF and Chuck, I'm with you. A lot of boat builders offer AlgeX as an option and magnets in your fuel system do nothing. I bought into this scam back in the seventies. We sold a few and then had to refund the money when they didn't work.
Maybe. My own experience with a De-bug unit was on a Sabb in a sailboat. The Sabb only drew as much fuel as was burned - no return line to the tank. After a few years, the Racor was collecting black gunk in the bowl causing all kinds of problems. I installed the De-bug, did nothing else and the problem went away.

And there is some research on the effect of magnetic fields on bacteria. Certainly some bacteria that contain ferrites are magnetic, although I have no idea if these bacteria can feed on hydrocarbons and cause problems in fuel tanks. Here is a link to a company selling such devices, with the study they funded being published in a the journal Biofouling in 1999. Is it good science? Beats me, although a University did conduct the study, and it was published in a real journal, meaning it was peer reviewed. Purafiner, Diesel Fuel Protection

So, while I understand the skepticism, my personal experience doesn't agree and the idea that magnetic fields disrupt the biology of bacteria and fungi/molds isn't false.
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Old 02-19-2013, 10:15 PM   #24
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So, while I understand the skepticism, my personal experience doesn't agree and the idea that magnetic fields disrupt the biology of bacteria and fungi/molds isn't false.
At considerable risk to my own reputation...or should I say what's left of it...I agree with the above statement! No need to inundate this thread with numerous claims of witchcraft, I've heard it all before. My experience with magnetic fields and fuel, although not exactly what Delfin has experienced, is strikingly similar. And that's all I have to say about that!
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Old 02-19-2013, 10:47 PM   #25
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The last time I spoke to a rep trying to flog ultrasonic antifoul at a boat show, he backed away from the claim that the device will prevent growth and claimed that " it will make your antifouling last longer..."

If it worked it would be OEM on all new boats..
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Old 02-19-2013, 11:14 PM   #26
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high frequency sound waves can liquify glues and other materials as well causing fractureing. Dosen't sound like a good thing to expose your bottom to if you ask me. but its your bottom
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Old 02-20-2013, 06:01 AM   #27
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here is a few tests:

Testing Ultrasonic Antifouling | Sail Magazine

http://content.yudu.com/A1lm9o/Ultra...the_month.html

page 2/3.

http://content.yudu.com/A1qwi5/Ultra...5598%26templat

page 2/3

http://www.sailingmates.com/ecoantifoul2.htm
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Old 02-20-2013, 10:05 AM   #28
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These tests crack me up. They all put fresh bottom paint on the boats and then attribute the lack of growth to some extent on the ultrasonic instead of the bottom paint. None of this, in my mind is an indicator of whether this works and is worth the money. But my offer to sell my system that runs off a 9 volt battery for half the price of the ultrasonic still stands for anyone. Chuck
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Old 02-20-2013, 04:56 PM   #29
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This is from another forum, where the discussion is also going on, there are several other universty studies:

Her is a study extract, not exactly sure what the verdict is:
""
Inhibition of barnacle cyprid settlement using low frequency and intensity ultrasound.
Guo S, Lee HP, Teo SL, Khoo BC.
Source
Department of Mechanical Engineering, National University of Singapore, Singapore, 117576. gsf830@hotmail.com
Abstract
Low frequency, low intensity ultrasound was demonstrated as an effective inhibitor of barnacle cyprid settlement. When the same substratum vibration amplitude (10.05 nm) and acoustic pressure (5 kPa) were applied, ultrasound at a frequency of 23 kHz significantly reduced cyprid settlement. The mechanism appeared to differ from the ultrasonic cavitation induced inhibition previously reported as no increased mortality was observed, and no change in the exploratory behaviour of cyprids was observed when they were exposed to this continuous ultrasonic irradiation regime. The application of ultrasound treatment in an intermittent mode of '5 min on and 20 min off' at 20-25 kHz and at the low intensity of 5 kPa produced the same effect as the continuous application of 23 kHz. This energy efficient approach to the use of low frequency, low intensity ultrasound may present a promising and efficient strategy regarding irradiation treatment for antifouling applications.
PMID: 22296259 [PubMed - indexed for MEDLINE]
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Old 02-20-2013, 05:41 PM   #30
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This is from another forum, where the discussion is also going on, there are several other universty studies:

Inhibition of barnacle cyprid settlement using low frequency and intensity ultrasound.

Low frequency, low intensity ultrasound was demonstrated as an effective inhibitor of barnacle cyprid settlement. This energy efficient approach to the use of low frequency, low intensity ultrasound may present a promising and efficient strategy regarding irradiation treatment for antifouling applications.

If we're still talking about vibrational frequencies sufficient enough in strength to disturb the cyprid settlement of barnacles, I'd like to see the laboratory comparison between the above vs. the frequency of Lawrence Welk's Disco Freakout Album broadcast at the same strength.
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Old 02-20-2013, 05:51 PM   #31
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I think that it is 23 kHz that has proven to be "better" at discouraging the barna-things to attach. They don't discuss if they used 1000KW of power or 0.6milli watt to have an effect..(the article say 5 kPa but I don't know what kPa means - does anyone know what this means?)

I am pretty sure that the varying frequencies from the Disco will not have the same effect - whatever wattage is used..
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Old 02-20-2013, 08:49 PM   #32
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all I know is that my bottom gets enough vibration without me hiring someone to do it for me!
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Old 02-20-2013, 10:39 PM   #33
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I think that it is 23 kHz that has proven to be "better" at discouraging the barna-things to attach. They don't discuss if they used 1000KW of power or 0.6milli watt to have an effect..(the article say 5 kPa but I don't know what kPa means - does anyone know what this means?)

I am pretty sure that the varying frequencies from the Disco will not have the same effect - whatever wattage is used..
kPa is kilopascal, a measure of pressure. They are using the sound waves to create a higher than ambient pressure. Dividing by 7 (0.145) approximates the value in psi.
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Old 02-20-2013, 11:40 PM   #34
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MacGregorSailors.com • View topic - Sonic AntiFouling? Anyone with experience?

This link will take you an old thread - one of the post describes that the systems are also used for attracting fish......I guess this will take the discussion in another direction..
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Old 02-21-2013, 06:00 PM   #35
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MacGregorSailors.com • View topic - Sonic AntiFouling? Anyone with experience?

This link will take you an old thread - one of the post describes that the systems are also used for attracting fish......I guess this will take the discussion in another direction..
fish attractor????....will check er out thanks
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Old 03-14-2013, 08:46 PM   #36
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Just had a chance to HEAR a very old ultra sonic antifoul system from Barnaclean - the system that was mentioned as attracting fish.... It is a very simple system and it comes with a timer switch, for stopping the system temporarily - say overnight...

It is very loud - ticking every 3-4 seconds...and it is a very distinct, short burst of energy. The noise will probably be much less in a hull..

I tried one transducer on a bucket of water, the transducer outside and a hand inside..The pressure waves were very easily felt and I can understand why critters or barnacles would not like these waves...not saying that it works, just that it is annoying for any living creature....thus the timer function...
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Old 03-17-2013, 03:11 AM   #37
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Years ago I worked on a 92 metre processing trawler with ultrasonic transducers to pick up schools of fish at 1500 metres water depth. Serious units indeed and a whole lot more powerful than any recreational stuff. Every trip (9 week average) we had to clean bio fouling off the transducer face. Just saying.
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Old 03-17-2013, 03:29 AM   #38
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Good point, does any regular users of transducers have critters or barnacles on their transducers?

Nightcap, was it just regular bio slime or were there any critters or barnacles?
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Old 03-17-2013, 11:47 AM   #39
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Good point, does any regular users of transducers have critters or barnacles on their transducers?

Nightcap, was it just regular bio slime or were there any critters or barnacles?
Regular rec boat ransducers up to 1000 watt usually foul if everything else is fouling. I don't have any experience with the 3Kw and higher.
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Old 03-17-2013, 03:07 PM   #40
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It was slime and weed, we never left it long enough for the barnavles to grow.
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