Ultrasonic Anti-Fouling

[Alan Wheeler]

Simply put, it can not be done unless you have enormous power and concentration of the sound. Simply not possible on a boat. You would need every square inch of hull covered by transducers and the power required simply wouldn't be feasible on a boat.
What I don't understand is, how come these snake oil makers don't get sued for the dribble they try and sell. What is stopping me from creating a special black box that has a couple of LED's indicating a power on and a working indication and say that, When the unit is on, it sets up a special force field around the boat the deters all marine life from want to grow on the Hull. Then produce a heap of glossy brochures full of all the BS and sell the thing as the new wonder technology. Either these people are completely delusional or have no morals. Surely at some point they must realise the product doesn't work.

[Karletto]

i agree with above + remember that the sensor/ transmitter is on the inside of the hull -> 1 more minus from me

[drh1965]

Originally Posted by Alan Wheeler

Simply put, it can not be done unless you have enormous power and concentration of the sound. Simply not possible on a boat. You would need every square inch of hull covered by transducers and the power required simply wouldn't be feasible on a boat.
What I don't understand is, how come these snake oil makers don't get sued for the dribble they try and sell. What is stopping me from creating a special black box that has a couple of LED's indicating a power on and a working indication and say that, When the unit is on, it sets up a special force field around the boat the deters all marine life from want to grow on the Hull. Then produce a heap of glossy brochures full of all the BS and sell the thing as the new wonder technology. Either these people are completely delusional or have no morals. Surely at some point they must realise the product doesn't work.

Yeah, build a lightning protection system that is guaranteed to prevent 99.9% of all lightning strikes. I love those types claims. Unprovable. Not quantifiable. Just BS! People would buy it and swear up and down they've not been hit by lightning since the gee-wiz device was installed! The guys that gets hit will be the unfortunate .1% or a bad install job

[lolanreg@smartc]

nmit I also saw that supersonic gadget at the Sydney Boat show. If it works as they say you'll be in front by the time you sell your boat. At least you can put it in the next one, $4000 is a lot of money, but so's cleaning and the paint. just hard labour to me. Did it for 40 yrs. Go for it then tell me it's great! Natureboy Ps wan't there some great stuff there?, oh to be a rich man diddle, diddle dee.

[lolanreg@smartc]

Alan W, Course it wont kill the NZ ones they're too strong not like these pathetic aussie ones who will give up on the least excuse. I did try some NZ Sheep Lanolin some years back didn't work either probably needed a pair of gumboots to gather it off the sheep farms. Natureboy

[S/V Antares]

You might check out the companies that went out of business doing this. One of them bought custom transducers from a company I worked for. They (The company) are gone and several thousand of the transducers are still there in a box.

AW knows sound. IMHO 20 watts will not clean your teeth much less your bottom (Sorry, had to say it) Snake oil

[Alan Wheeler]

I tried Lanolin last year too. But it was a hell of a fight to get the sheep to put it's head under water. I will see in October if it worked or not. But I think I have a more major issue with the Sheep. It runs off every time I pull out my flippers, mask and snorkel. Does anyone have any remedies for Sheep suffering from Anxiety??

[Wotname]

First good laugh I have had for days - Thanks Wheels

[Chief Engineer]

But Constable, I was just helping this sheep over the fence.

[Steve Pope]

Alan I can send you a small jar, it still smells pretty sheepish. It is what the shepherds take to town with them in case they feel lonely and none of the local girls march up.

[Wotname]

Wheels, what have you started here????????
(and where are the TDP's when you need them - Thread Drift Police)

[Steve Pope]

OK my apologies re assisting the thread drift.
To get the thread back on track we need some of the Aussie folk who have these things fitted to give us a heads up on how successful / or not, they are.

[jjtctaylor]

For all the nay-sayers out there, it appears there is a beginning groundswell of evidence that ultrasonics do kill algae. Just google for it. A boat is a logical extension of that application.

I did find one website with a fairly even documentation of a 2 year boatsonic test with outcome as reasonable as could be expected. Less effective depending on distance from sender and thickness of hull (resistance to resonate).

www.thomas-electronics.be/ documenten/reference-boatsonic-2007.pdf

Hull is just a an extension of the sound horn. Won't give 100% coverage but 80% is pretty good result. Not sure how well it does on mammals but looks like ultrasonics really messes up algae. Now whether it functions to clean or kill, not sure anyone will tell or care as long as it does something.

Bigger questions is foam core, or solid hull more conducive to wave propagation, or can vendors adjust frequency and amplitude depending on hull types, materials, thickness etc. for best performance. That may be where you pay your big money.

JT

JT

[Alan Wheeler]

If you do a web search "ultrasonic Algae control" for instance, you come across screeds of information. Spend some time working through it and a couple of themes arise.
I have found a couple of points of concern and a couple of contradictions. Certainly there seems to be something in the claims of Ultrasonics and pond Algae control.
The one major concern I have is the frequency. One article suggested that the best freq was 28Khz. Another found 15-21.5Khz the best range. So which is it. But I am mostly concerned that this range is still very much in the audible range of much of our marine life.
The next issue is what can be controlled. There are 27000 different species of algae and 47000 variations of that within the group. So far 5 types have been unaffected by ultrasonics. It seems that plants and fish are unaffected. So what exactly is being controlled on a boat hull. Boat hull cleaning would mean plant and fish life (as in shellfish) would need to be affected. So there are some contradicting statements being given here. One of the companies involved in hull cleaning show a boat being lifted from the water. Claims are that it has little growth. Well it looks just like my boat when it is hauled and I don't have a sonic device. The test really should have a "control" subject and the test subject. And the claim that there was no weed and shell growth except where the keel was submerged in the Mud. But the boat hull was certainly covered in algae. So isn't that what the device is supposed to best at killing?
I don't know. To sum up, I think there maybe something in pond control with Ultrasonics. But I would love to talk to some pond people that have tested and used the product before I am convinced. As for boat control, there is just too much that doesn't add up. I am not going to say it won't work, but from my own knowledge of sound and from the contradictions I have read, and the fact that the frequency is so low and in an audible band to marine life, I am not convinced at all.

On a slightly similar but different subject. I thought it terribly sad about the young whale they had to put down in Oz. It lost it's mother while still suckling and was dying of starvation. One can only assume it's mother was most likely hit by a ship. This is becoming more common and I think a great deal could be done at not a lot of cost, in regards to some kind of Sonic device being placed in the bows of ships that send a sound out in front to warn Whales of a ship approaching.

[David M]

Maybe a hydrophone with the sound of orcas? No idea if that would work.