Once again Im heading towards that painful $3000 anti fouling exercise and thinking again about whether ultrasonic transducers really work to stop growth on a hull. Supposedly it does but finding proof is really hard.

Perhaps this is a way to find out:- Yesterday went for a nice sail up and down Pittwater. This morning I realised I left the power on on the boat by mistake (for the beer fridge), but including the fish finder/depth gauge. It occurred to me to not turn it off but to wire it so its alway on and after a month or three when the boat gets slipped have a look under the hull near the fish finder and see if theres less growth?

What do Seabreeze gentlemen (and others!) think? Everyone leave their fishfinders on all the time (wire them direct to batteries) and in a few months we should have a result? Let me know if you want to join in.

I think you'd be lucky to get useful results. Fishfinders usually operate at ultrasonic frequencies above 50kHz and up to 200kHz, whereas as ultrasonic antifoulers, such as the Jaycar kit, operate in the lower 20 kHz and 40 kHz band, i.e., barely beyond the audible range. Apparently different algae respond to different frequencies. YMMV.

Besides, I would advise against leaving anything hardwired to your batteries, except bilge pumps.

The basis of ultrasonic anti fouling originated exactly from less growth under sonar transponders on navy ships and many fish finders use the same bands today.

Who knows if Jaycar used the appropriate bands. The whole idea of my suggestion is to find out instead of making untested assertions.

There's little difference between hard wiring a fridge, bilge pump, AIS transponder, or sonar transponder to the batteries. It would be prudent to use a fuse that's all.

The Jaycar kit is based on a published design that was tested and worked - at least in some circumstances. I'll try and track down the article.

From my research, the important thing in any ultrasonic antifouler is the ability to scan across a range of frequencies, so as to maximise the disturbance that inhibits algal growth. A single frequency _may_ work but it would involve a great deal of luck. Different algae respond to different frequencies.

By hard-wiring I thought you meant a hard-wired connection to your battery! I'm just saying that all electrical equipment on board should be behind a fuse or circuit breaker, with the possible exception of your bilge pumps.

I bought the Jaycar kit but never put it together, it was easier every year to pick up the phone and book an anti foul!

The experiment is simple - everyone leaves their fish finder on and at next slipping take a look at the hull under it. Im leaving mine on now full time, at max depth setting so its cranking out some power, and when the boat is slipped in a month or so will have a look.

My hope here is if everybody does same, with different fish finder/depth instruments, in different environments, and with different hull type we might get an amazing result like on boat X with brand Y fish finder there is reduced growth under the fish finder. If someone really does find reduced growth it might be worth putting in an effort into researching it properly.

We have mega $$$ to save if we find something good and cut out anti-fouling costs. Not to mention helping the environment.

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Trek said..
I bought the Jaycar kit but never put it together, it was easier every year to pick up the phone and book an anti foul!

The experiment is simple - everyone leaves their fish finder on and at next slipping take a look at the hull under it. Im leaving mine on now full time, at max depth setting so its cranking out some power, and when the boat is slipped in a month or so will have a look.

My hope here is if everybody does same, with different fish finder/depth instruments, in different environments, and with different hull type we might get an amazing result like on boat X with brand Y fish finder there is reduced growth under the fish finder. If someone really does find reduced growth it might be worth putting in an effort into researching it properly.

We have mega $$$ to save if we find something good and cut out anti-fouling costs. Not to mention helping the environment.

Hi, one of my neighbours at the mooring field has an older swanson and he went down the jaycar kit route and found that there was a small reduction in growth, particularly in areas where a bulkhead or similar was fitted to the hull.

It's not the electronics that's the problem. If you think about it, it works by shaking the fouling off. The difficulty is the hull needs to vibrate, and that is a lot harder to do at the points where it is stiffened by bulkheads etc.

being an acoustic system, there would be a considerable amount of trial and error involved in finding the best place to mount the transducers to the hull. when fitting a system, being able to measure the energy being transmitted by various hull areas would be really helpful...

I had 2 of the Jaycar units on my previous boat. Yes they did work, but only just. You might get 6 months extra between slipping. The way I could tell it was working was that I never had to remove the log paddle wheel which was near the front unit for cleaning and the one over the propeller probably kept it fairly clear of growth, but apart from that I could see no other difference. I didn't consider it worth installing on my new boat.

were they the MKII units, or the first version?

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fishmonkey said..
were they the MKII units, or the first version?

Could not be sure, but I installed them in 2012. 5 years ago.

I have had a system for several years.
Does not perform as per all the hype.
But does work to an economic level as I have got more than my money back and halved antifouling.
Biggest problem is if one does not use their boat frequently then the dead algae stays on and still barnacles of some types get a hold.
Frequent boat use makes a big difference.
Sadly I do not use my boat any where near enough.

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warwickl said..
I have had a system for several years.
Does not perform as per all the hype.
But does work to an economic level as I have got more than my money back and halved antifouling.
Biggest problem is if one does not use their boat frequently then the dead algae stays on and still barnacles of some types get a hold.
Frequent boat use makes a big difference.
Sadly I do not use my boat any where near enough.

Intrigued and as a total novice in this, I googled. The units are on special at the moment: https://www.jaycar.com.au/kit-ultrasonic-antifouling-for-boats/p/KC5498, $159.20, almost $110 off. The feedback on the Jaycar site is interesting .

Tim

that kit is discounted as it was superseded by this updated version in 2017:

www.jaycar.com.au/ultrasonic-antifouling-kit-for-boats/p/KC5535

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fishmonkey said..
that kit is discounted as it was superseded by this updated version in 2017:

www.jaycar.com.au/ultrasonic-antifouling-kit-for-boats/p/KC5535

From my experience one would need a few kits/transducers depending on boat size and construction to get any benefit.
Also suitable power supply eg I have a dedicated 160 watt solar panel with a 200 amp hour battery with boat on a swing mooring.
I have 3 full sized transducers and 2 mini tranducers.
Boat is a 34ft Rivera.
The system I have is not a Jaycar kit.

The Deckside Marine Ultrasonic Antifouling - Long Term Review - Part 1 is now available here.
www.deckside.com.au/blog/post/ultrasonic-antifouling-review-part-1.html

Ultrasonic Antifouling is viewed by the boating fraternity as either hocus pocus or as a cost effective antifouling solution. This review will hopefully dispel the myths and give some clarity to the long term benefits.

Most tests we read are performed after 12 months or less, which is the normal period between antifouling. They all show a cleaner than normal hull which is expected. But what happens when we extend this period.

Not sure how to respond to a review like this Darren!

Funny how these topics seem to come up, just yesterday I was looking at the mk11 Jaycar system. $249 plus around $100 for a second transducer. The little barnacles we have in the Port Hacking are my nemisis. My boat was AFed with Micron 66 in August, and I have already scrapped off barnacles around the waterline, and I have
bought this, see picture to try and attend to the lower regions. Obviously I hope I don't damage the paint but I'm not going to put up with barnacles till next August!

Good thing if your keen on diving on your own boat! But keen also here more experiences with various ultrasonics.

cheers Richard