Prop damage/repair

[tobble]

Hello

found some shallow pitting all over my prop on lift out. is this a serious problem, and can I repair it easily? I was thinking along the lines of fairing with epoxy.

I think this was due to the annode not working properly as it was covered in a white oxide layer /forums/images/graemlins/frown.gif Have recently moved into Cardiff bay so having a new magnesium jobbie fitted which should stop it happening again...

the boat is a sabre 27, only metal bits in the water are the bronze prop, ss shaft cutlas and a few skin fittings. no P bracket

 

[Topcat47]

It depends on what you mean by "shallow". My prop was marked by shallow pits, but there were scratches on the surface deeper than the pits. It was more pock marked than pitted. Hours of work with wet & dry and Brasso removed most of them and a liberal application of propguard seems to have kept them at bay. At no time was there a poor connection between the prop and the anode, I checked with a multimeter on lift-out, something I do every time. Anodes develop a white oxide layer as they erode and it's not something I'd worry about on alone.

Fairing a prop with epoxy is no less work than polishing it properly and the epoxy layer will be a magnet for weed and crustacians, if it sticks all over the brass, which is doubtful.

 

[paulwitney]

After twenty years of antifouling boat bums and props I have come to accept that any bronze prop will have some pitting. A well seated anode on the shaft is a MUST and will help prevent major corrosion but it's a harsh world down below!! When antifouling I have found PA10 primer (International Paints) applied after a quick sand down of the prop and then a coat of antifoul while primer is still tacky gives a good bond. I then give the prop another 2-3 coats of antifoul. This has consistently lasted for over 11 months but by then some growth is starting to appear. Then it's into the water for a quick scrape off of prop and a wipe over of the hull as I did today in readiness for our twilight racing series. (At least it keeps you active!)

 

[omega2]

www.clementsmarine.co.uk talk to Paul Williams

 

[PeterGibbs]

Shallow pitting - not a structural problem. No advantage in filling out, much as you might want a smooth prop.

Do you have the right anode for the water the boat is moored in? Presume you know zinc is for salt water?

If the coming season results in even deeper pitting, you clearly have circuit/anode problems.

I see a lot of folks splashing regular AF paint around their props and shafts - when you look at the small print on the tin, you don't do that. Either use a proprietary paint for metal or nothing at all.

PWG