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Offtopic Marine: Anyone built their own ultrasonic antifouling system? (solar powered of course)

willo

Solar Enthusiast
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Apr 8, 2020
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So I learned that ultrasonic antifouling systems exist yesterday and of course, I immediately searched for transducers - they seem cheap enough in the 50-100w range. I'm thinking that this could be an opportunity for my DIY side to have some fun.

Since this would definitely run off solar, it's related. Swear!

I've found a few papers on the topic, which should be helpful for tuning frequencies, power levels, etc.

Example commercial system:


Bare transducer example:
 
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SUPER cool idea. unda da sea there r so many creatures.

all i would say is be careful! water can conduct sound really well and i’m a total amateur when it comes to underwater ultrasonic anti fouling systems.

i used a virtual reality wireless hand stimulator array one time at an expo.. it was a square grid array of upward facing ultrasonic transducers that would time delay beamform ultrasonic pulses to your hand based on where the camera said the hand was. they had invisible objects on the screen that could be “touched” but it just felt like a tiny buffet of wind or something. anyways i digress.

the booth person said that it’s about as loud as a jet engine at the hand focus point, so i definitely kept my face/ears away from it, haha..

i’ve bought components from BQLZR before and had decent results.

good luck on your projects!
 
I’d like to chime in to hear if you were able to accomplish this! Tell us about it! I recently acquired a small pontoon boat. I would like to fully equip with solar as well as this type of antifoul system. I would like to not have to reapply a copper based antifoul every year or two!
 
No but have been looking for some time. The issue I have is what will high frequance do to my plastic fantastic hull? Delamination...... its probably OK for the tin hull boys
 
I think Nordkyn's boat was fiberglass wasn't it? What is to cost & specs of the one you found?

No Aluminum, but he says

The nature of the hull coating doesn’t matter, at least as long as it is not compressible and vibration-damping. Very soft ablative antifoulings should make less sense with an ultrasonic system, you can’t extend the life of the paint if it can’t be cleaned without coming off. The intrinsic antifouling properties of copper-epoxy coats seem unimpressive, but it could be an attractive option if you intend to clean it periodically, because it is very hard-wearing. Based on my experience, I would expect an ultrasonic system to make it considerably easier to clean when it becomes necessary.

When it comes to hull materials, solid glass reinforced plastics have given very good results with some ultrasonic systems, so the material is clearly capable of transmitting the energy. I definitely expect good results, but here again, it takes at least months if not more to obtain data and I only deal in straight goods, no marketing garbage with pictures of freshly water-blasted hulls!
A very important aspect is always transducer installation. Transducers need to be mounted so they can “vibrate” the hull skin, so away from stiffeners, and they must literally become part of the hull. Some of the commercial transducers are built in such a way that this simply cannot happen properly.
 
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Note that Nordkyn writes about improving the drivers to have higher peak frequencies to help reduce the .


The code changes to the ultrasonic driver had three effects:
  1. Increasing the maximum frequency used by the system from 41kHz to 65kHz;
  2. Increasing the amount of energy allocated to the higher frequencies;
  3. Increasing the overall average output power.
The performance of a properly built and installed ultrasonic system should be a function of:
  1. Its peak power output, as peak power determines the “reach” of the system over the hull surface, as well as the maximum amount of damage it can potentially inflict to marine growth on the hull surface;
  2. The average power delivered, as it seems that damage from low-power ultrasonic energy results from cumulative exposure over time;
  3. The frequencies used, possibly because higher frequencies tend to be intrinsically more energetic, but it may also be that shorter wavelengths are able to excite damaging resonance effects in algal cells.
The table below summarises the consumption of the system with the original firmware as well as the new one, in its two modes of operation. In this test, the new firmware only ever operated in its low-power mode, due to the limited solar energy available at the time. In summer, it will switch to the higher output at least for a part of most days.

Average Power
[W]
Energy Consumption
[Ah/day]
Original Firmware5.910.7
New Firmware (Low Power)11.019.8
New Firmware (High Power)14.725.6

The firmware changes nearly doubled the average output power of the system, and its consumption.
 
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