I would agree with what Dwight said on a theoretical level. Heck, my engineering training and boating experience gave me the same opinion before I started asking around.
I don't really know what is in the Pettit two-part primer, but I know it etches the metal and seems to form some sort of bond. Looks sort of like an epoxy coating after it cures. And I've seen the 4 bladed props on a friend's 35 ft trawler after a full year of fishing, and there was still a good coat of black Trinidad Pro, no noticeable erosion, and nary a barnacle. So somehow it works. Rick -----Original Message----- From: CnC-List [mailto:[email protected]] On Behalf Of Graham Collins Sent: Tuesday, January 08, 2013 9:41 PM To: [email protected] Subject: Re: Stus-List Prop Mussel Farm I have to disagree with that Dwight. My previous boat had a Volvo saildrive with an aluminum prop. It was original (20 year old) factory paint on it when we got it, but the change in mooring location was enough to prompt a few pounds of barnacles to live on it, which destroyed the paint Volvo had applied. After a couple of trials, what worked was applying Interlux Primocon and a couple of coats of bottom paint, with the aluminum I had to use Tri-Lux II. No issues with the paint coming off, I would just apply a new coat of antifouling in the spring and never had to put on more primer. I did not see exposed metal anywhere, including the tips. Graham Collins Secret Plans C&C 35-III #11 On 2013-01-08 8:05 PM, dwight veinot wrote: > Sorry Rick > > But I don't think the primer will add much unless it too is an > antifouling paint. > > Under the influence of tip vortex and face sheet cavitations on the > prop blades, especially at high rpm, most paints will be removed, > regardless of and including most primers...IMHO best you can hope for > with antifouling paint is to give better fouling protection to the > shaft and hub of the prop where I believe the effects of cavitation > are less severe, and some shorter term protection to the blades which > I would suggest might last longer if the boat were driven at lower rpm > rather than full out > > Dwight Veinot > C&C 35 MKII, Alianna > Head of St. Margaret's Bay, NS > > -----Original Message----- > From: CnC-List [mailto:[email protected]] On Behalf Of > Rick Brass > Sent: January 8, 2013 7:52 PM > To: [email protected] > Subject: Re: Stus-List Prop Mussel Farm > > In North Carolina we don't have much problem with mussels, but the > relatively warm water, moderate currents and abundance of nutrition in > our rivers and sounds lead to constant struggle against a lot of barnacles. > Being a multiple boat owner, I've had a lot of experience over the > years and paid a lot for divers to clean my props. > > The last straw for me was when I took the 38 to Beaufort for some work > in the summer of 201. Hull speed is about 7.3 kts, and I motored down > there at 6.5+. Why not? The boat had been splashed just 3 months prior > and the bottom job was brand new. On the way home, about 3 weeks > later, I could make only about 4 knots. Man, were there a lot of > barnacles on the (unpainted) prop and shaft. And since I planned to > take the boat south it seemed like I better do something to avoid future growth. > > Once I got the prop cleaned, and since I've already tried bottom paint > on the prop and shaft (it does not stick very long if you use the > motor very much - call it 100-150 NM of motoring in my case), I > started asking to see what others in the area do. > > The information that I got is that the commercial fishermen in the > area usually paint the prop and shaft after using a two-part primer > that will let the paint stick. The primer is a two-part product called > Pettit Metal Primer #6455. You clean all the old organic material off > the prop and areas of the shaft that will not be covered by the zincs > (I actually sanded with 80 grit until it was shiny and well scratched > up, but was told this was not necessary), mix the primer, and paint it > on. After 24 hours of cure time you put on bottom paint. The preferred > paint in these woods seems to be Pettit Trinidad Pro. I was told that > ablative paint like Micron 66 and Pettit Ultra will stick, but slough off fairly quickly as the boat is used. > > The Pettit primer wasn't particularly cheap - about $65 IIRC for about > a pint of primer after mixing. But if it will make the bottom paint > stick it is probably a good value. And the local fishermen, who use > their boats 5 or > 6 days a week pretty much year round, seem to swear by it. > > It's only been on my prop for 6 months or so, but so far I'm very > happy with the results. > > Of course, your results may vary. > > > Rick Brass > Washington, NC > > > > -----Original Message----- > From: CnC-List [mailto:[email protected]] On Behalf Of > Robert Abbott > Sent: Monday, January 07, 2013 1:55 PM > To: [email protected] > Subject: Stus-List Prop Mussel Farm > > there is one more 'remedy' I have heard/read about......it involves coating > the prop/shaft with "galvanized zinc spray paint". I have never seen this > done and do not know what effect it might have on the bronze prop > (shouldn't be negative but I'm not sure). There is never any marine > growth on my sacrificial zinc(s). > > Has anyone heard of this? Anyone with any experience with this paint > on props? > > Bob Abbott > AZURA > C&C 32 - 84 > Halifax, N.S. > > > > > > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com [email protected] > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2221 / Virus Database: 2637/5518 - Release Date: > 01/08/13 > > > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com [email protected] > > _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com [email protected] _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com [email protected]
