Paprika, chili peppers, diaper rash ointment, tetracycline powder . . . now you can add pet sedative to the list of potential antifouling agents that have been or are being investigated.
Several alert Practical Sailor readers passed on news reports regarding new research by Professor Anders Blomberg at the University of Gothenburg in Sweden. Blomberg reports that his team, along with researchers in Finland, has discovered the gene that reacts to a medetomidine, a veterinary medicine that has been shown to prevent barnacle larvae from attaching to boat hulls.
According to the article, medetomidine activates genetic receptors in barnacle larvae and the receptors emit a signal that causes the barnacle larvae to swim away. Blomberg says very low concentrations of the substance are needed to drive the barnacles away.
Experiment results, which are published in the scientific journal Molecular Pharmacology, suggest that such research could produce an effective antifouling coating that deters barnacles without harming the environment. The identification of the gene also raises the possibility of creating genetically modified barnacles that have no appetite for boats coated with certain substances.
Mutant barnacle larvae? Sounds like a surefire blockbuster in 3-D.
Look for our latest report on antifouling paints in the October issue of Practical Sailor.
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{ 4 comments… read them below or add one }
Lightening Strikes Blow Out More Than Electronics
By Cliff Moore
Your articles documenting long-term testing of bottom paints have been very interesting and helpful. Over the years, I have discovered that Interlux ACT has worked well for me, and I’ve used if for over ten years. I especially like the green color, which contrasts nicely with my red boot stripe. This year, however, I discovered an interesting problem, which some of your your readers may have encountered.
My sailboat, a 30-year-old Paceship PY-26, was launched the week before Memorial Day in Raritan Bay. That weekend, I sailed it and confirmed that everything was working: the batteries, connected to solar panels and a regulator, were charging, that the Yanmar diesel started and all systems were go; that the lights worked, and so on.
Memorial Day evening, after I left the boat, a swift moving storm whipped through, with lightening that struck several boats, including mine. The first clue I had of that was the following weekend, when I looked at the masthead and soon discovered that the wind indicator was missing. Also, that the VHF antenna was history, as was the radio itself, the stereo, depthfinder, the nice new LED masthead lights (and one interior LED), and eventually through the summer, other odds and ends, such as the holding tank level indicator, the battery combiner, the solar panel regulator, and the engine hour’s meter. All toast. The really expensive stuff – GPS plotter, starter, alternator, batteries – were OK.
I thought, on the whole, I that I got off easy, as I read a number of real horror stories not long afterwards concerning damage by lightening to boats: blown-out engines, fried starters and alternators, sunk boats. The entire level of damage I experienced didn’t rise to my deductible, so I grit my teeth and replaced burned-out equipment as I found it. Why complain about the loss of a 30 year old VHF? It didn’t owe me anything.
But there was one puzzling phenomena that I at first attributed to the unusually warm water I had been sailing in: there seemed to be far more barnacles than ever before. Although I used very heavy grease on the prop to keep of aquatic growth, it had ¼” of barnacles on it within two weeks, and pretty much needed cleaning every two or three weeks throughout the summer, even on my annual cruise into cooler, cleaner New England waters. Also, I was seeing barnacles where I had never had them before. Generally, when I get them, it’s under the keel or where the jack stands rested; never anywhere else, and only at the end of the summer. This year, I had to scrape barnacles three or four times, including Labor Day Weekend, when I found heavy growth below the waterline.
Imagine my surprise when I pulled the boat during the first week of October and found even more of them! They were in a curious patter – almost all were within the top 18″ below the waterline; none below that or on the keel. However, I still thought it was simply the affects of warm water and the turbid waters of Raritan Bay – sometimes it’s like sailing through sheep deep at a state fair. More proof of global warming, I thought.
This fall, I attended the Annapolis Boat Show and started describing the lightening strike to someone. He told me about a friend whose boat also had been hit: he had used copper bottom paint and after a month, it had ½” of barnacles all over the bottom.
Ah, ha! I made the connection: lightening strikes, intense AC high-voltage current, may drive the copper out of soluble copper bottom paint, or in some way, de-ionize it.
I believe that when the lightening struck my boat, a certain amount discharged evenly along the waterline, like water dumped from a bucket from great height would splash 360 degrees, dissipating along the surface of the sea, and not necessarily at the keel.
Naturally, this is something for experts to pursue, but I can’t think of any other explanation. I used the same bottom paint I always used, ACT; a friend with a similar sized boat in the same waters uses the same paint, bought from the same source, with no ill-affect other than a few barnacles on the keel, as he usually experiences.
So, if you’re boat has taken a lightening hit, check the bottom.
(BTW, I have photos.) Best wishes, and thanks for the great articles over the years!
Fascinating hypothesis. I’ll see what we can dig up.
Cliff,
We’re still following up on this. A few questions from the technical experts at Interlux, who have not heard of this before:
Was there a noticeable or abnormal color change?
Was there any surface defects such as blistering or cracking?
What is the mast bonded to (Keel or thru-hulls)?
It looks lie the copper-thieving lightning theory remains intact. Sorry about the delay. Magazine deadlines intervened.
Jim Seidel at Interlux likened this to an effect called “burn back,” which occurs when improperly primed metal comes into contact with antifouling paint. Because copper is less noble that stainless or bronze, the copper will degrade first, and the paint will lose its antifouling properties. The areas of copper-deprived paint will eventually spread to surrounding areas of the hull, not just metal components..
Here’s Jim’s take; “My theory is that when the lightning hit the mast, it traveled to where it could get to ground, and maybe the quickest way was through a thru-hull which was painted with antifouling paint but not enough primer, and through the copper in the paint made contact with other metals around the boat. This caused the copper to degrade within a couple feet of the waterline and not further down. In this case, maybe it was a good thing that there was not a lot of primer on the underwater metals because it may have caused more damage in the boat.”