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Discussion Starter · #1 · (Edited)
Hi All,

Traveler is on the hard while I install a new PSS, a couple of through hulls and get the bottom painted. Today we saw a boat next to us get it's prop and prop shaft painted grey. They taped the zince before paint. What kind of paint can be or should be applied to the prop and shaft? I just cleaned mine up, bronze prop, shiny SS shaft. I know it won't stay that way long. what do you recommend?

Dave
 

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Oh, here again?

If your prop really really is bronze (and not some brass) and you do not use any zinkanode ... then there is no need for painting the prop. The Cu in the bronze will act as a antifouling, (very) slowly realising Cu+ ions.
If a zink anode is attached (most do this as they are not 100 % certain that the prop is made of bronze), then Zink ions will be released instead of Cu, and there is no antifouling effect.
If the prop is made of brass, and no zink anode is used, then the Zink in the brass will be released, similar to the case above, and no antifouling effect and with time the zink in the brass will have decreased considerably and the brass is very much weakened (and good-bye Mr Prop).

Where I live we put the boats on the hard annually. Dutifully most boatowners paint their props with some special prop paint, extra expensive. Purpose of the paint is to get some antifouling effect as most boatowners are not completely sure that their props actually is made in bronze (rightfully so, looking at prop manufacturers homepages very few declares material used), so most add some zink anodes and then there is a need for something giving antifouling effect as a prop with barnacles is not a healthy prop.

/J :)
 

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Discussion Starter · #3 ·
Thanks J,

I'm going to guess I have a good bronze prop. We hauled the boat last August for the survey prior to purchase. The prop was dirty, as was the shaft, but no barnacles or pitting of any kind. Hauled it and pressure washed it Friday, 8 months later, dirty again, but no pitting, corrosion or barnacles. The zincs are working, the boat isn't leaking and at the moment, my area of the marina is not hot. I'll put it back together and let good enough be. Thanks,

Dave
 

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They put that grey paint on my prop in Trinidad in November. 6 months of cruising later, the prop has some weed but no barnacles. I don't remember what it was called (it was very reasonable) and I'm still not sold on it, but it may be helping. However, we rarely use our engine, so I'm not sure of the durability of that paint under normal engine use; I'm pretty sure we'll be back to a scraper and wire brush pretty soon, though.
 

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Here in NZ everyone seems to use a gold-colored product called Propspeed. it's not antifouling but some super slick compound that keeps growth from adhering. i am skeptical but it seems like everyone that gets hauled out here (and pays the yard to do the labor...maybe there is something here) uses it. also, it must be applied by a licensed technician. just out of curiosity, i asked the guy applying it to the trawler next to me to give a quote for 1.5" prop shaft, maybe 3 feet, and prop. NZD$220--OUTRAGEOUS!! i'll just hop over the side every so often with a scraper and brush and take care of it for that price.

Edit: Wow, i just looked and WestMarine sells it...for an arm and a leg but it doesn't appear you have to have someone apply it for you in the US
http://www.westmarine.com/detco-marine--propspeed-foul-release-system--P008706814
 

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The grey paint is probably Pettit's Prop Coat Barnacle Barrier - see link for more info - Prop Coat Barnacle Barrier

This product does a pretty good job on preventing barnacle growth on underwater metals, including props. And it is inexpensive - $25 to $35 a can depending on where you buy it. One can is more than enough to do a prop on most sailboats.
 

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Several Manufacturers make it, Interlux's version is called Trilux. In my experience, it works. Even one or two barnacles on a prop will dramatically reduce efficiency and boat speed.
 

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+1 for Propspeed. When I was on the north shore of MA, I didn't need it. Here on the cape at my dock I've seen water temps as high as 80 degrees in August. Without a coating, I've spent 30 mins with a scrapers and dive gear to remove barnacles (I'm talking the whole prop was white, nothing exposed!). With Propspeed it stays clean. Downside, "wicked expensive"

I think it depends on where you keep the boat and what kinda stuff likes to attach itself in your neighborhood.
 

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Jnoiur Mebemr
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The gray could be Interlux 2000. At our yard, they will often apply a barrier coat (to prevent contact between the bronze prop and copper in the antifouling) followed by 3 coats of regular non-ablative antifouling. According to what the yard workers say, it works much better than propspeed and you can expect to get 1-2 years out of it depending on use.
 

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I used Pettit's Prop Coat Barnacle Barrier this year. Last year the prop wasn't painted and it came out positively horrid looking. With a clean prop, I easily made 6 knots when the boat was splashed yesterday; I was happy to make 5 knots at the end of the season last year.
 

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I also use three thin coats of Petit Barnacle Barrier. It works fairly well for one-season application. Infinitely cheaper than Speed Prop. The prop should be brought down to bare metal and then rubbed down with acetone or MEK before applying.
 

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Several Manufacturers make it, Interlux's version is called Trilux.
Interlux Trilux 33 does come in an aerosol spray, like Pettit Prop Coat Barnacle Barrier, but that's where the similarity ends. Barnacle Barrier is a hard, zinc-based product that cannot be used on fiberglass and wood while Trilux 33 is an ablative, copper-based paint with an additional anti slime biocide and requires a primer before being used on bare metals. The Pettit product requires no primer.
 

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Barnacle Barrier is a hard, zinc-based product that cannot be used on fiberglass and wood while Trilux 33 is an ablative,
Have there been a lot of "fiberglass and wood" props on the boats you've been cleaning lately?
Perhaps something is getting into your air supply?
 

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Have there been a lot of "fiberglass and wood" props on the boats you've been cleaning lately?
Perhaps something is getting into your air supply?
Trilux 33 is an anti fouling paint that is formulated to be used not only on running gear, but boat hulls as well. Barnacle Barrier is not. Had you taken the time to actually read the thread you would have understood that I was replying to a post that inferred that the two products were essentially the same, which they are not. I described the differences.
 

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Re: Painted prop - a (very) recent development

Well, without going into the deeper philosphical issues ...
Whatever. Just telling you what the manufacturer says about the product. If you want to use it in a manner that runs contrary to the manufacturer's instructions, well, it's your dime and your prop.
 

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Trilux 33 is an anti fouling paint that is formulated to be used not only on running gear, but boat hulls as well. Barnacle Barrier is not. Had you taken the time to actually read the thread you would have understood that I was replying to a post that inferred that the two products were essentially the same, which they are not. I described the differences.
Oooo. Somebody woke up cranky bears this morning.
 

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The gray could be Interlux 2000. At our yard, they will often apply a barrier coat (to prevent contact between the bronze prop and copper in the antifouling) followed by 3 coats of regular non-ablative antifouling.
I checked with the Interlux customer service folks last year about Interlux 2000 insulating aluminum from the copper in a typical bottom paint. Their response was that Interlux 2000 does not effectively prevent galvanic action in this case and advised me not to use copper bottom paint.
 
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