My prop on my Beneteau 321 just split in two down the center. Lord knows why. Anyway, a new one is on the way. Does anybody know if a salt water boat should have its propeller painted before installation? Does a "bottom job" on a prop make a difference.
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Because my boat is idle
much of the time, I paint the prop but not the zinc. You should look closely at the broken prop to learn why it failed. Even to the extent of taking it to a metalurgist. It could have been a bad casting but more likely a case of electrolytic corrosion. Be sure to install new zincs on a clean shaft.
much of the time, I paint the prop but not the zinc. You should look closely at the broken prop to learn why it failed. Even to the extent of taking it to a metalurgist. It could have been a bad casting but more likely a case of electrolytic corrosion. Be sure to install new zincs on a clean shaft.
Painting your prop
I have found that painting the prop and shaft only works if you put a layer or two of primer under the paint. The theory is that the copper in the bottom paint reacts electrically with the metal in the shaft and prop and inhibits its antifouling properties. In the past I have used Interlux Interprotect 2000E as a primer under my hard epoxy paint but it was a pain to apply. For the past few years I have used the spray-on outdrive paints with primer (Interlux Trilux with Primocon primer). These are much easier to use and have performed well in the brackish water of the bays along the New Jersey coast. Of course, the more you use your boat the less fouling you are likely to get. Which ever method you use, clean the prop and shaft well - down to bare metal - before applying the paint and do not paint or prime under or over your zincs.
I have found that painting the prop and shaft only works if you put a layer or two of primer under the paint. The theory is that the copper in the bottom paint reacts electrically with the metal in the shaft and prop and inhibits its antifouling properties. In the past I have used Interlux Interprotect 2000E as a primer under my hard epoxy paint but it was a pain to apply. For the past few years I have used the spray-on outdrive paints with primer (Interlux Trilux with Primocon primer). These are much easier to use and have performed well in the brackish water of the bays along the New Jersey coast. Of course, the more you use your boat the less fouling you are likely to get. Which ever method you use, clean the prop and shaft well - down to bare metal - before applying the paint and do not paint or prime under or over your zincs.
Thanks Ross and John
I appreciate your input. I'll definitely take the old prop to somebody for an inspection. The diver said he'd never seen anything like it in his life. I had the boat out just three weeks ago for a bottom job and everything looked fine. Anyway, I just want to make sure my new prop doesn't get fouled right away. Sounds like paint is the answer.
I appreciate your input. I'll definitely take the old prop to somebody for an inspection. The diver said he'd never seen anything like it in his life. I had the boat out just three weeks ago for a bottom job and everything looked fine. Anyway, I just want to make sure my new prop doesn't get fouled right away. Sounds like paint is the answer.
Rick: Unless you had a bad casting, you have a Maj
Your prop shouldn't EVER break in half. Unless it was a bad casting, the fact that your prop broke indicates that you probably have an electrical problem either on your boat or near your dock. Stray electric currents will rapidly corrode under water metals. Both AC and DC currents will eat metals like they were candy, and if this is your problem, your new prop will go away too. Steve Alchemist
Your prop shouldn't EVER break in half. Unless it was a bad casting, the fact that your prop broke indicates that you probably have an electrical problem either on your boat or near your dock. Stray electric currents will rapidly corrode under water metals. Both AC and DC currents will eat metals like they were candy, and if this is your problem, your new prop will go away too. Steve Alchemist
Rick, you didn't mention the condition of
the zincs. With an electrical problem the zincs will go first and it can be quite quickly. by way of comparison my propeller shaft zinc is still servicable after two years. And yes everyone, there is continuity between the zinc and the propeller.
the zincs. With an electrical problem the zincs will go first and it can be quite quickly. by way of comparison my propeller shaft zinc is still servicable after two years. And yes everyone, there is continuity between the zinc and the propeller.
Yes, it should be painted to help prevent...
marine growth on it. A hard copper based paint will do. Make sure you periodically check your shaft's sacrificial anode and replace promptly (before it is more than 25% gone) You can engage a diver to do this for you priodically as well as cleaning the hull.
marine growth on it. A hard copper based paint will do. Make sure you periodically check your shaft's sacrificial anode and replace promptly (before it is more than 25% gone) You can engage a diver to do this for you priodically as well as cleaning the hull.
Zinc
I would bet that the zinc was not replaced frequently and galvanic corrosion destroyed the prop. I have a B-331. They use a very small Zinc at the end of the shaft (Jeneau Jr.). Unfortunately there is no room between the skeg and the prop to install a collar zinc on the shaft. My diver replaces the zinc every 2 months because it is completely gone.
I would bet that the zinc was not replaced frequently and galvanic corrosion destroyed the prop. I have a B-331. They use a very small Zinc at the end of the shaft (Jeneau Jr.). Unfortunately there is no room between the skeg and the prop to install a collar zinc on the shaft. My diver replaces the zinc every 2 months because it is completely gone.
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