Ultrasonic antifouling

[Bigsfish]

I’m not an expert on anything (ask my wife) but some are experts on cleaning growth on hull bottoms. I would heed that persons advice.

 

[Mambo42]

Am reading reactions here that some have hull cleaning performed almost every month and I can't help but asking myself: 'isn't it time for a different anti-fouling ?'

Currently I am running some sort of test (not voluntarily btw) with 2 different types of anti-fouling on my boat. The hull has copper coat, the stabilizers have international anti fouling. Boat has been in the water now for almost 1.5 months after the stabilizers were installed and this week i took a look at the whole boat while we were anchored in a bay.
The copper coat is completely clean, not even a slimy layer on it. The international anti-fouling on the stabilizers however is already starting to show some growth. I had to scrape it off and can't say I was happy to see that growth after only 1.5 months.

Why do I have 2 different types of anti-fouling ? I basically ran out of copper coat (read: had not ordered enough) after they had installed the stabilizers. Forgot that the bilge keel was removed and that needed to be redone with copper coat as well.

In other words, instead of sending a diver every month in the water to clean your hull.......isn't it an idea to take a different type of anti-fouling ?

 

[mvweebles]

.........In other words, instead of sending a diver every month in the water to clean your hull.......isn't it an idea to take a different type of anti-fouling ?

Any suggestions? Florida is the #1 state in the US for boat registrations. There are a LOT of people who would love to know if this is possible. 3-4 week dive schedule is not unusual in these waters, at least in the summer months. Seems hard to believe - in San Francisco, my diver disappeared and I went almost a year. Bottom wasn't too bad. Hard growth is not much of a problem.

Peter

 

[fstbttms]

Any suggestions? Florida is the #1 state in the US for boat registrations. There are a LOT of people who would love to know if this is possible.

It is not possible. If it were, do you think somebody would be keeping it a secret?

 

[RT Firefly]

Greetings,
Bottom line is: If it worked, it would be FAR more common on the docks. People would talk about it, businesses would try to sell systems instead of bottom paint or at least mention it as a viable alternative.
Major shipping firms and the military would use it.
The ONLY time I ever hear about it occurs when someone asks about it on a boating forum.
MY $0.02.

 

[PierreR]

Ultrasound probably works within a fairly narrow frequency. The minute you shoot it through a hull you introduce all kinds of ways to change frequency. Especially with laminate defects or coring. Frequencies would need to change for every boat and material.

 

[mvweebles]

It is not possible. If it were, do you think somebody would be keeping it a secret?

I agree. I was stunned at how frequent bottoms are done in Florida. Tough to comprehend if you haven't seen it first hand.

 

[Patrick4002]

my personal experiance

Hello, I had a lot of growht on my previous boat and cleaned
it yearly, one year i put a epoxy couting on an installed the ultrasonic on without antifouling so i has a hard surface. the installer worn me to not use a soft antifouling as the prevent the uslrasonic from breaking the first layer of growht. I was the a harbor master in Zeebrugge Belgium, i got in the summer almost 50cm long growt like a small underwater forest. (due to my work we did not get out a lot) a diver from the windmill park was near my boat busy and ask't if he had to look on the state of my hull.

He came back and askt me what i did fore antifouling, he mention that there was a big growt but i did't stick to the hull he could just sweep it off.

i also made a big green soup round the boat when moving out of the dock

i have installed set of 4 transducers to my current boat but have not been out of the water yet the system i have use a pattern of different frequenty
the result of the current installation i see in the spring.

antifouling is here big business so no shop is promoting any other system.
i had order my set in australie

i see it more in use for bigger ships to protect pumps and sometimes the hull

 

[r67113g]

Not a fan

I have a 33 foot trawler in south FL. I installed one of these systems when I first brought the boat to FL. Because my boat is all aluminum it should work better then on a fiberglass boat. I don’t believe it does anything at all.

 

[Mambo42]

Any suggestions? Florida is the #1 state in the US for boat registrations. There are a LOT of people who would love to know if this is possible. 3-4 week dive schedule is not unusual in these waters, at least in the summer months. Seems hard to believe - in San Francisco, my diver disappeared and I went almost a year. Bottom wasn't too bad. Hard growth is not much of a problem.

Peter

I have had quite a few different anti-foulings on the boat by now, but last year I changed to copper coat since I was tired of getting the boat out every year, sanding it and putting new anti-fouling on it. Also had to get a diver twice a year, which also added up to the cost.
Now that I have the copper coat for almost a year in total I dare to say that I see a difference. I have not cleaned the boat at all, came out of the water in July and was perfectly clean. And since it has been back in the water the hull is also still clean.
The water temp is about the same as in Florida, but there could be a big difference in nutrients in the water. That, I cannot comment on, I just don't know. However, with the other anti-foulings I did have quite a bit of growth after a couple of months.

I have also been paying attention to other boats when they come out of the water. Boats with copper coat all tend to be clean, with hardly any growth, the boats with the hard black anti-fouling (like e.g. international), or the dissolving anti-fouling, usually have growth or even barnicles in any shape or form.
And now that I have 2 different types of anti-fouling on the boat I can really see the difference after an equal amount of time.

Again, I won't say that copper coat will work perfect in Florida, but when you have to pay a diver every month to clean the hull I think I would just give it a try. It is a bit more expensive than normal anti-fouling, but if it would save you 10 dives a year you already have recouped the cost. If you then also don't need to haul out the boat every year, sand it and put anti-fouling on it, you really start saving a lot. And of course, no growth on the boat will give you a better performance in the water.


As for the prop shaft, rudder and prop itself I did find a difference between prop speed and prop jet. I used to have prop speed only, but since they were working on the rudder and prop shaft I had to replace a part. They did not have prop speed, but prop jet and must say that prop jet works not as good as prop speed. At the moment the prop speed is completely clean, the prop jet is starting to become slimy, which means growth will follow soon. So cleaned it this week and should be ok again, but I do see the difference.

Hope this info can be of help to others.

 

[Mischief Managed]

One of those systems was installed on a boat in my marina over the Summer. Did not appear to do a thing, there's was a massive salad growing on it weeks after the install. Not impressed.

 

[Patrick4002]

some thinking

when i put my electronic antifouling on the installer told me that plants still grow on the bout but they cannot stik very well to the hull as the first layer of the plant are dead from the ultrasonic, i had to go 8kn or 10 kn to get rid of the most

the diver told the same story lots of plant but could wipe them off very easy wit the hand.

im no expert, this is just wat i experianced

 

[Blissboat]

Ultrasonic antifouling devices may or may not annoy barnacles, but I seriously wonder what dolphins and other marine mammals think? Sound travels a long way in the water, and maritime mammals are highly evolved to depend on underwater sounds. From that perspective, it's hard to imagine that anything good could come of underwater ultrasound. Even if I believed it deterred bottom growth, I wouldn't use it. Marine mammals have enough problems, as it is. Seeing them is one of the great joys of being out on the water.

 

[fstbttms]

I seriously wonder what dolphins and other marine mammals think?

Here ya go:

https://scripps.ucsd.edu/news/ultrasonic-antifouling-devices-found-damaging-whales

 

[Blissboat]

Here ya go:

https://scripps.ucsd.edu/news/ultrasonic-antifouling-devices-found-damaging-whales

Good sleuthing, Fast. That solid evidence should be unsurprising, but it is helpful to have the facts to confirm common-sense judgement.

 

[RT Firefly]

Greetings,
Mr. B. HAH! How common is sense?

 

[Blissboat]

Greetings,
Mr. B. HAH! How common is sense?

Hah! Fair point, RT, although would you not agree that here on the TF common sense occurs at least slightly more often than out in the general population? Better not answer that - my common sense says we're about to get busted by the thread-drift police!

 

[Wdeertz]

After reading mixed reviews on hullshield I bit the bullet and installed 8 pucks on my boat last month. I hauled out in July 2023 and had 3 coats of anti foul paint applied. Given Tampa Bay warm waters historically I’ve needed to clean my hull at least every 3-4 weeks. I dived my hull after installing the system and cleaned the small amount of growth since haul out. I plan on doing a video review next month after 8 weeks since installation. Historically I’ve needed to do 10-12 cleanings per year, if the hullshield can cut this in half I’ll consider it a success. Will post a link here after doing the video.

As previously mentioned I posted a video of my experience. Take it for what it is https://youtu.be/9Syf3YqY7QU

 

[fstbttms]

[QUOTE=Wdeertz;1209564]As previously mentioned I posted a video of my experience. Take it for what it is https://youtu.be/9Syf3YqY7QU[/QUOTE]

The fact that there are any barnacles in the proximity of your emitters (especially since the bottom had just been painted) is evidence that you ultrasonic system is not performing as advertised.

 

[Wdeertz]

[QUOTE=Wdeertz;1209564]As previously mentioned I posted a video of my experience. Take it for what it is https://youtu.be/9Syf3YqY7QU

The fact that there are any barnacles in the proximity of your emitters (especially since the bottom had just been painted) is evidence that you ultrasonic system is not performing as advertised.[/QUOTE]

Not sure how you came to the conclusion there were barnacles near the emitters. I withhold any final conclusion but take any conclusion by you as biased given your vested interest. ?

 

[fstbttms]

Not sure how you came to the conclusion there were barnacles near the emitters.

The fact that you placed an emitter specificlly at the bow thruster (mentioned several times in your video) and yet the majority of the barnacles present were on the bow thruster leads me to that conclusion.

 

[SteveK]

Is there any before video for comaprison?

 

[Offshore]

You still have to haul and paint the bottom on your regular intervals so save your money.

 

[Wdeertz]

The fact that you placed an emitter specificlly at the bow thruster (mentioned several times in your video) and yet the majority of the barnacles present were on the bow thruster leads me to that conclusion.

As I said don’t know how to explain the bow thruster but there definitely was little growth on the stern thruster. All I can think is the two hull emitters in the Lazarette are also providing some cover for the stern thruster. The two forward emitters in the bow are further back from the bow thruster. Only time will tell.

 

[Wdeertz]

Is there any before video for comaprison?

Boat was hauled and painted July 2023. The light growth from the 2 intervening months before system installation was thoroughly cleaned.

 

[Wdeertz]

You still have to haul and paint the bottom on your regular intervals so save your money.

Not about saving money, about avoiding the hassle of cleaning the bottom. (Installation costs was <2% of my last 12 month spend on the boat). If you watched the video the objective is not to eliminate bottom cleanings but to cut in half. For boats that move around a lot it’s a hassle finding a diver (or doing yourself) to clean the bottom.

 

[mvweebles]

...If you watched the video the objective is not to eliminate bottom cleanings but to cut in half. For boats that move around a lot it’s a hassle finding a diver (or doing yourself) to clean the bottom.

As mentioned on the other thread, halving bottom cleanings is a reasonable expectation and would be compelling if demonstrable. The issue I have is the actual data is murky. Anyone who has unsatisfactory results is brushed aside with comments from the manufacturer that the system must not have been operated correctly, usually that they user must not have provided 24/7 or the bottom paint still needs to be renewed. Their position is the system works well. If it doesn't, not their fault. Yet they provide scant objective data (such as a twin-study in a catamaran) conclusively demonstrating efficacy.

I remain hopeful (but decreasingly optimistic) that someday non-anecdotal evidence will convince me. Until then, I'm on the sidelines.

Peter

 

[SteveK]

Boat was hauled and painted July 2023. The light growth from the 2 intervening months before system installation was thoroughly cleaned.

Thanks, but was looking for a visual of what was cleaned one of the dozen times a year.

 

[O C Diver]

As I said don’t know how to explain the bow thruster but there definitely was little growth on the stern thruster. All I can think is the two hull emitters in the Lazarette are also providing some cover for the stern thruster. The two forward emitters in the bow are further back from the bow thruster. Only time will tell.

As a curiosity, how were the transducers attached to the tunnels? I would assume the effectiveness would be based on thickness of the hull, distance of the area from the transducers, and contact area of the transducer to the surface it's protecting. Did you build up the tunnel with fiberglass so that the transducer was 100% in contact with the tunnel?

Another question would be: How do you determine each transducer is functioning properly? I recently had to replace an 8 year old video depth sounder transducer. While you could hear it clicking, the signal and or return had degraded over a few year, until it quit displaying depth or any bottom return. Was wondering if there was a way to determine if the transducers were functioning properly?

Ted

 

[Wdeertz]

As a curiosity, how were the transducers attached to the tunnels? I would assume the effectiveness would be based on thickness of the hull, distance of the area from the transducers, and contact area of the transducer to the surface it's protecting. Did you build up the tunnel with fiberglass so that the transducer was 100% in contact with the tunnel?

Another question would be: How do you determine each transducer is functioning properly? I recently had to replace an 8 year old video depth sounder transducer. While you could hear it clicking, the signal and or return had degraded over a few year, until it quit displaying depth or any bottom return. Was wondering if there was a way to determine if the transducers were functioning properly?

Ted

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.