Sonihull Ultrasonic Antifouling Install

Stout said:

From Marine industry news:

https://marineindustrynews.co.uk/sonihull-ultrasonic-anti-fouling-system-used-by-dutch-mod/

BY GINA GROOM JUNE 3, 2020, 10:48AM

“ Sonihull Ultrasonic Anti-Fouling system used by Dutch MoD
Lamers System Care recently installed the Sonihull Ultrasonic Anti-Fouling system on 11 landing-craft vessels for the Dutch Ministry of Defence, to keep them free from algae, weeds and other biofouling.
The Royal Dutch Navy, along with its worldwide fleet and personnel, is committed to maritime safety and the protection of the marine environment. With sustainability in mind, the Ministry of Defence chose Sonihull’s ultrasonic system to provide an environmentally safe solution for the anti-fouling of its landing craft.
A Landing Craft Vehicle Personnel (LCVP) is a small vessel designed for the transportation of vehicles or personnel. The type MkV (c) can transport up to 35 fully equipped personnel. The LCVPs are stationed in a protected nature reserve. As a result, anti-fouling coatings that contain toxic chemicals cannot be applied to the ship’s hull in case harmful substances end up in the nature reserve’s water.
Because traditional biocide-based anti-fouling can’t be used, the ships’ hulls are colonised by algae, weeds, barnacles and other biofouling very rapidly. This growth on the LCVPs results in increased fuel-consumption, reduced speed, damage to the hull, and reduced lifespan of the vessel, which is not desirable.
The Sonihull ultrasonic anti-fouling system creates microscopic ultrasound-induced cavitation on the surface of the vessels. This disrupts the first stages of the food chain, without damaging the surface being protected. The action prevents the build-up of algae, slime and bigger, more complex organisms on surfaces where biofouling is not wanted. The system is silent and the movement of water on the protected surface also prevents the adhesion of juvenile barnacles and mussels.
Each of the LCVP units has one Sonihull DUO system, which consists of a control box and two transducers. The transducers are installed on the inside of the vessels to protect the hull from fouling. Instead of the standard composite transducer rings that are glued in place, aluminium mounting rings are used. The rings are bonded to the aluminium hull using a 2-part epoxy resin. The Dutch Ministry of Defence opted for aluminium rings so that it is possible to weld them to the hull if they ever need to be re-located.
The control boxes are connected to both the 220 VAC (shore power) and the 24 VDC, so that the systems remain active 24/7. Due to the extremely low energy consumption (7.2 Watt per transducer), this has no significant impact on the vessels’ energy management.”

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Thanks for the article. I hope they post results. I'm going to copy your post onto the thread I started on the Sonihull long term test:

https://www.trawlerforum.com/forums/s32/sonihull-ultrasonic-antifouling-install-47771.html

Thanks to Stout for posting this on another thread about ultrasonic antifouling:

From Marine industry news:

https://marineindustrynews.co.uk/son...-by-dutch-mod/

BY GINA GROOM JUNE 3, 2020, 10:48AM

“ Sonihull Ultrasonic Anti-Fouling system used by Dutch MoD
Lamers System Care recently installed the Sonihull Ultrasonic Anti-Fouling system on 11 landing-craft vessels for the Dutch Ministry of Defence, to keep them free from algae, weeds and other biofouling.
The Royal Dutch Navy, along with its worldwide fleet and personnel, is committed to maritime safety and the protection of the marine environment. With sustainability in mind, the Ministry of Defence chose Sonihull’s ultrasonic system to provide an environmentally safe solution for the anti-fouling of its landing craft.
A Landing Craft Vehicle Personnel (LCVP) is a small vessel designed for the transportation of vehicles or personnel. The type MkV (c) can transport up to 35 fully equipped personnel. The LCVPs are stationed in a protected nature reserve. As a result, anti-fouling coatings that contain toxic chemicals cannot be applied to the ship’s hull in case harmful substances end up in the nature reserve’s water.
Because traditional biocide-based anti-fouling can’t be used, the ships’ hulls are colonised by algae, weeds, barnacles and other biofouling very rapidly. This growth on the LCVPs results in increased fuel-consumption, reduced speed, damage to the hull, and reduced lifespan of the vessel, which is not desirable.
The Sonihull ultrasonic anti-fouling system creates microscopic ultrasound-induced cavitation on the surface of the vessels. This disrupts the first stages of the food chain, without damaging the surface being protected. The action prevents the build-up of algae, slime and bigger, more complex organisms on surfaces where biofouling is not wanted. The system is silent and the movement of water on the protected surface also prevents the adhesion of juvenile barnacles and mussels.
Each of the LCVP units has one Sonihull DUO system, which consists of a control box and two transducers. The transducers are installed on the inside of the vessels to protect the hull from fouling. Instead of the standard composite transducer rings that are glued in place, aluminium mounting rings are used. The rings are bonded to the aluminium hull using a 2-part epoxy resin. The Dutch Ministry of Defence opted for aluminium rings so that it is possible to weld them to the hull if they ever need to be re-located.
The control boxes are connected to both the 220 VAC (shore power) and the 24 VDC, so that the systems remain active 24/7. Due to the extremely low energy consumption (7.2 Watt per transducer), this has no significant impact on the vessels’ energy management.”
__________________
Cheers, Kevin

I posted earlier about my experience with Clean-A-Hull. I hauled the boat this week and want to update my comments. Some history: Boat hauled and paint touched up sept 2018. Zincs changed by diver in July 2019. Diver was going to clean hull but said there was nothing there to clean. Boat hauled this week, June 2020. There was a little slime but no grasses. A few barnacles on the prop but none elsewhere. Other boats in my marina grow lots of grass.

Waterford said:

I posted earlier about my experience with Clean-A-Hull. I hauled the boat this week and want to update my comments. Some history: Boat hauled and paint touched up sept 2018. Zincs changed by diver in July 2019. Diver was going to clean hull but said there was nothing there to clean. Boat hauled this week, June 2020. There was a little slime but no grasses. A few barnacles on the prop but none elsewhere. Other boats in my marina grow lots of grass.

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Which bottom paint do you use?

Are you in open or covered moorage?

I don't know what brand it is, but it is a hard paint. It was on the boat when I got it and it was only touched up last year. The boat is moored in the open in southern Puget Sound.

If the boats hull underwater is solid glass , these can work.


If however it is a cored bottom do not expect good results.

Doug,
Is that photo before pressure washing and as it came out of the water?

That was taken as it came out. Nothing but a little slime.

FF said:

If the boats hull underwater is solid glass , these can work.


If however it is a cored bottom do not expect good results.

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There is a procedure to install the acoustic transducer on cored hulls. The inner skin and coring is removed and the transducer mounted to the outer skin.

I agree that the results would be diminished even with the transducer glued to the outer skin. I think the foam attached to the outer skin would attenuate the vibrations.

Stringers, bulkheads and other hull reinforcements on glass hulls can also reduce the effectiveness of the transducer. Manufacturers recommend installing the transducers away from supporting structure.

The analogy is a musical drum. Stike the drum head in the center and it will be the loudest. Strike towards the rim and the volume will be reduced.

Metal hulls will transmit vibrations more effectively than fiberglass which is why ultrasonic antifouling works so well on large commercial metal hulls.

Waterford said:

That was taken as it came out. Nothing but a little slime.

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That is impressive.

Just so you know... They do not clean the hull; you must start with a clean hull. Then they keep it clean, but must run 24/7, even while cruising. So, there is a battery draw to consider. Check the specs of the model you are using. It was suggested to me that I go with four transducers even though their brochure said 2 would work. Maybe 2 would do the same thing, but I'm very pleased with four.

I keep my boat in water all year in brackish water while at home. I usually have it short hauled for cleaning and bottom paint in the spring. Normally the growth is minimal on the hull when starting a new season. However, the last couple of years (I do not know why) there has been substantial growth, with barnacle's on the props, shafts and rudders and not so much on the hull itself. In researching the two systems (CleanHull & Sonihull) I have been leaning towards the CleanHull Quad, so I could place a transducer above each prop / struts and the another midship.

Am I on the right track? Based on your picture the system obviously works well (impressive, you sold me!). Did the props and running gear fair as well?

Thanks!
Dave

Sounds like Sonic Snake Oil.

IntoTheBlue said:

I keep my boat in water all year in brackish water while at home. I usually have it short hauled for cleaning and bottom paint in the spring. Normally the growth is minimal on the hull when starting a new season. However, the last couple of years (I do not know why) there has been substantial growth, with barnacle's on the props, shafts and rudders and not so much on the hull itself. In researching the two systems (CleanHull & Sonihull) I have been leaning towards the CleanHull Quad, so I could place a transducer above each prop / struts and the another midship.

Am I on the right track? Based on your picture the system obviously works well (impressive, you sold me!). Did the props and running gear fair as well?

Thanks!
Dave

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I can only speak to my experience on my boat in my waters so I don’t know if your props and running gear will improve. In my case, I used to get a lot of mussels inside my thru-hulls but don’t now. I still get a few barnacles on the prop, but that was not a problem I was trying to solve. I think that placement of the transducers and the distance to the prop hardware might be the determining variables.

I have seen folks report limited success with these things. If you are just trying to protect your running gear, maybe it will work. Have you compared the price of this thing versus several years of diver services?

Recently, have you changed the brand of bottom paint?

rgano said:

I have seen folks report limited success with these things. If you are just trying to protect your running gear, maybe it will work. Have you compared the price of this thing versus several years of diver services?

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Last spring the running gear was so covered with growth I could not power up the boat. I did the dive myself to clean it up, but there is a real problem in the Great South Bay and that is you can't see your hand in front of your face under water. So diving is not a good option.

This is why once I saw an article about ultrasonic antifouling in Passage Maker I've been looking into it. It seems that the growth happens during the winter while docked in a brackish canal. My hope would be to find a solution to keep the bottom clean during this period.

Thanks!

OldDan1943 said:

Recently, have you changed the brand of bottom paint?

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No, done by the same marina for years. The hull though is not the problem. Just the running gear. It is odd, I've kept the boat in water in a canal off the Connetquot River for years, with minimal growth found in the spring.

Last year was the worse, but again only on the running gear. The hull was clean. One thought was the mild winter.

Waterford said:

I can only speak to my experience on my boat in my waters so I don’t know if your props and running gear will improve. In my case, I used to get a lot of mussels inside my thru-hulls but don’t now. I still get a few barnacles on the prop, but that was not a problem I was trying to solve. I think that placement of the transducers and the distance to the prop hardware might be the determining variables.

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Thanks for the quick reply. One quick question on the placement of your transducers. Are they mounted over the prop's?

Thanks again>

Finally, pictures of Sandpipers bottom to show the result of having the Sonihull installed and run continually for 9 months.

I went on the drygrid for my twice annual bottom inspection and paint touch up in late September. I went on the grid in May but my phone ran out charge and was unable to take pictures.

Attached below are pictures from September. There were a few small barnacles (less than 20) on the prop, which is painted with cold galvanizing paint. Two or three small barnacles in the bow thruster tunnel.. Usually there are more medium sized barnacles.

The hull was covered with whiteish "stuff". It was not strongly stuck to the hull and could be wiped off with my finger. I think it is dead algae. There was no green live algae or waterline grass visible. The bottom, at the usual September dry grid inspection, is covered completely with green algae and long grass at the waterline.

The white stuff did not appear to be as thick during the May inspection, but not a big difference.

I think the white stuff would wash away if I drove the boat around for a couple miles. Sandpiper has not been used since December 2019, when I had the bottom cleaned by a diver. With C19, we decided to skip boating for the year so the boat has had zero use.

The vertical streaks in the white stuff are water running down the hull and washing it down as the hull drys. The dark areas are the paint showing through the white stuff.

The distance from the boathouse to the grid is a short distance and a no wake area so not enough to dislodge the white stuff.

I don't consider this to be a good year for this test since the boat was not used in a regular fashion. The results seem positive but since Sandpiper has been sitting still for 9 months in a boathouse, the amount of sun it received was minimal. The boathouse roof does have 25% clear panels. We are usually out boating at least 3 months and the algae and grass grows very quickly while cruising in the summer.

The bottom must have had some algae growth because of the white stuff. If that is actually dead algae. I don't know what else it could be. I think that if the boat was used more, the dead algae would be washed off by the moving water as it dies and not accumulate.

The positives are the small size and number of barnacles on the prop and thruster tunnel.

I'm going to call the result inconclusive until next year, when we get back to normal and go boating.

I installed Sonihull Ultrasonic Antifouling on my boat last fall and am conducting a test.

See the results at:

https://www.trawlerforum.com/forums/s32/sonihull-ultrasonic-antifouling-install-47771-2.html

Help me understand what is expected. It seems as bottom painting is maintained as before. It seems that this device then should keep slime and grass off the bottom paint.
It seems that barnacles will be kept off.

If the sonic devices work that well, why do you need the bottom paint?
Yes I will also do some reading on the products.

Soo-Valley said:

Help me understand what is expected. It seems as bottom painting is maintained as before. It seems that this device then should keep slime and grass off the bottom paint.
It seems that barnacles will be kept off.

If the sonic devices work that well, why do you need the bottom paint?
Yes I will also do some reading on the products.

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I'm still skeptical about Sonihull's claims.

As I understand it, the SH will not work as well without paint.

My bottom never has barnacles. The prop and inside the thruster tunnel are the only places that gets barnacle growth. But very few.

Best of luck on your experiment. The product does not work with wood hulls. Even F/G hulls must be dense from my reading to transmit a vibration through the hull material.

Does Sonihull’s ultrasonic anti-fouling technology work on all types of material?
The only material that Sonihull does not protect from bio-fouling is wood.

The system relies on internal resonance to transmit the ultrasonic signals to the surface being protected. Compared to man-made materials, wood is full of varying densities and voids and is not an efficient transmitter of ultrasound.

Sonihull provides effective anti-fouling protection for solid materials, including Steel, Stainless Steel, Aluminium, GRP, FRP, Kevlar, Titanium and rigid plastics.

Note - The protection of certain concrete and ferro-cement structures will depend on their individual composition. Silicone-based coatings are known to dampen up to 40% of ultrasonic signals and will reduce system effectiveness. This can be compensated by decreasing the spacing between transducers.

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Not being a skeptic... but rather acting as a rational, logical thinker:

Why after years and years of boat owners' questions in the category of "What ifs", "Does it or doesn't it" and "Is bottom paint also required"?? As well as years of manufacturer and dealer statements regarding how great ultrasonic antifouling technology is and works... WHY are there seemingly never conclusive ultrasonic antifouling test results available??

Seems that IF there were actually an anti fouling system that works well [such as in the occasional anecdotal boat owner's report] that manufacturer of ultrasonic antifouling system would have conclusive test-evidence available to prove beyond a doubt that ultrasonic anti-fouling system work and exactly how well they work!!

To not have these "proven" positive-working [or, negative-working] test results available leads me to believe that positive-working results are not able to be produced... thinking rationally and logically that is!

Agree with Art. Conclusive test would be relatively easy - take a few large catamarans and install on one hull and not the other. Not doing so speaks volumes.

Peter

Ultrasonic antifouling is being used successfully for intake and outflow grates and pipes on municipal desalination plants, sewage and stormwater runoff etc.

UA is installed on ships with great results.

The examples above are made of steel or other metal which transmit vibration better than FG.

The commercial UA transducers are larger diameter than the Sonihull and transmit hundreds of watts of acoustic output.

mvweebles said:

Agree with Art. Conclusive test would be relatively easy - take a few large catamarans and install on one hull and not the other. Not doing so speaks volumes.

Peter

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I'm not sure why magazines have not conducted such tests.

Nigel Calder in Professional Boatbuilder magazine started a Sonihull test by installing them on his boat a few years ago. Never published a followup.

That makes me skeptical of these things.

syjos said:

I'm not sure why magazines have not conducted such tests.

Nigel Calder in Professional Boatbuilder magazine started a Sonihull test by installing them on his boat a few years ago. Never published a follow up.

That makes me skeptical of these things.

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"Nigel Calder in Professional Boatbuilder magazine started a Sonihull test by installing them on his boat a few years ago. Never published a follow up."

Follows my thought line exactly in post # 55.

I detest sales Bul Sht!

I just watched four [4] manufacturers’ [and/or merchandisers’] promo videos regarding ultrasonic hull cleaners. Not one had any stats listed nor any really understandable displays of the animated boat bottoms. You could latterly smell the Sales-Hype!

Following is an antidotal owner-excerpt [owner was not even there at the haul out to see and photograph boat’s bottom] from Sail Magazine article… liked here: https://www.sailmagazine.com/diy/testing-ultrasonic-antifouling

“The acid test came when the boat was hauled again in early November 2011, after a full six months in the water. During that time, aside from pulling random tufts of weed off the back of the rudder, I put no effort into keeping the bottom clean and did not once have the hull scrubbed. (In prior seasons, without the Ultra 20 installed, I had to have the bottom scrubbed by a diver two or three times during the year in order to keep the boat’s performance at an acceptable level.)
Unfortunately, I wasn’t able to attend Lunacy’s haul-out last fall, but the crew at Maine Yacht Center, where I store the boat, did a good job of snapping photos before giving her a pressure wash. I had hoped, of course, that the Ultra 20 would prove a silver bullet and that the boat’s bottom would be as clean as it had been the season before. As you can see from the photos, however, this was hardly the case.
Obviously there were certain areas of the hull that experienced significant growth. All in all, however, I am pleased with these results. I spent no money on divers, yet growth was moderate enough that I never really noticed any decrease in performance, even at the very end of the season. I was especially happy to see that both the keel’s vertical surfaces and the propeller blades were clean, and I do believe there would have been much more growth without the ultrasonic system running.
I should note that Lunacy did experience an unusually high amount of zinc wastage during the season. By the time she came out her propeller shaft zinc had disappeared entirely, her prop hub zinc was almost gone, and her two large hull zincs were about 40 percent depleted. The folks at Ultrasonic assure me their system has no corrosive effects, and I really can’t think of any reason why it should. I have to assume, therefore, that the zinc wastage is due to some change in the electrical dynamic of Portland Harbor, which is quite industrialized.
I should note, too, that the Ultra 20’s electrical consumption was within advertised parameters. The two ultrasonic transponders fixed to Lunacy’s hull consumed on average about 25 amps a day, and the boat’s two solar panels and one wind turbine had no trouble feeding this demand.
This season I’ll be renewing the bottom paint and switching to Pettit’s Ultimate Eco, an Econea-based paint I’m hoping will be more effective than the zinc paints I’ve used before. Hopefully, with a stronger paint to help it out, my Ultra 20 unit will keep the boat’s bottom even cleaner this year. The worst-case scenario, I figure, is that I may have to get the bottom scrubbed once during the year in order to keep it spotless.