ultrasonic antifouling

[splax]

Hello,
I was asked about ultrasonic antifouling and didn't even know that these systems were available. I would like to hear from those who have tried such a system to get a feel for how well they work and how safe they are for the boat.
The claim of extending the time between haul-outs seems reasonable, but perhaps not really a good thing in the long term since many problems you don't realize you have until haul-out. Keeping the bottom clean is good, but does the vibration cause the gel coat to allow water to the fiberglass and contribute to delamination? Is the current draw required acceptable for the power needed to work well? Are the electronics robust enough to last 5 years or more?
If you would like to contribute to the discussion, please relate your personal experience with the location and length of time.

 

[kloudie1]

I have looked at this technology since the mid 70's .. most of what I find is kinda sketchy .. The best report I found was applied on an aluminum hull where one would expect the sound to propagate much better than in fiberglass laminate.. http://www.sailmagazine.com/diy/ask-sail/testing-ultrasonic-antifouling/
I tend to have more confidence in Practical Sailor than I do in Sail since PS does no advertising.. They found it not so hot on fiberglass in the real world. http://www.practical-sailor.com/iss...trasonic-antifouling-test-update_10858-1.html
Over the years I have read that the sound is annoying and the power consumption is not small.. and antifouling paint is still needed.. I have not personally known anyone who's used it. The stuff I know about sound propagation (I am not even close to being an expert there!) would lead me to think that the useful sound/energy transmission would be attenuated significantly at every stiff point in the hull shell.. like in our H-34's, everywhere the structural grid is bonded to the hull..

 

[Maine Sail]

I have removed more of these systems than I ever knew were even sold. In fact I recall that I may have even removed a system from another SBO forum members boat..

In every single case they did absolutely NADA. Except of course for parasitically loading the batteries and putting a hole in the owners wallet. The owners who ponied up for them were all pretty pissed off that they could not see any differences in bottom conditions.

IMHO these devices are no different than copper bracelets, in other words a placebo.. How's that cayenne pepper (placebo) in the bottom paint working..? Oh and don't even get me going on "battery desulfators".....

 

[Rich Stidger]

Oh and don't even get me going on "battery desulfators".....

Uh oh. De-suftators are worthless?

 

[Stu Jackson]

Uh oh. De-suftators are worthless?

Yes, I tried one, never did squat.

For the OP: SNAKE OIL.

 

[Maine Sail]

Uh oh. De-suftators are worthless?

They certainly don't do what the name implies. I have approx seven years of testing data and not a single one of them has made a difference. I have tested the Sterling, PulseTech, BLS etc... A few hours at equalize voltage does more than 6 moths of a "desulfator".. They certainly can't hurt anything but they also don't seem to "desulfate" as the name implies they do.

BTW my testing has been far more scientific than any of the data these companies can provide. I have tested all batteries for Ah capacity as well as internal impedance changes using lab grade equipment which include a controlled temp water-bath... I just finished another 6 month stint three weeks ago. This was a pair of 105Ah batteries that were 1.5 years old, had less than 25 cycles, and came out of a parallel bank.. The batts had been mooring sailed, no solar, with a max charge voltage of 14.0V from a factory alternator. They were chronically under charged and suffering from sulfation.

Battery Baseline = Bat #1 - 75.6Ah and Batt #2 - 76.1Ah

Battery #1 - 4 hours of 16V
Capacity Test @ 77F 79.8Ah

Batt #2 - Six Month on a Battery Life Saver (No EQ, charged to full then set at float)
Capacity Test @77F 76.4Ah