Corrosion Protection for an OB Prop

[ebb]

Plan C,
A rubber bag that you pull over the lower unit and secure around the stern with bungies. Dump a little environmentally friend hydrogen peroxide down the well befor departing and bam! you've solved the problem!

[Theis]

Curiosity does not always bring forth the expected. Thanks to all the help, I now find there is a problem that I not only didn't realize I had, but one that I didn't even know could happen.

The battery ground and the lower unit have a solid electrical
continuity. However, the sacrificial anode, physically bolted to the cavitation plate, is not electrically connected. From the battery ground to the anode is an open circuit.

When I replaced the anode, I got continuity. I would never have thought that a solid connection between aluminum and zinc could become non-conducting.

So, for all you that leave your motors in the water, you now have another winter check up item. Take the anode off, clean it, and make sure it is electrically connected to the lower unit, not just physically connected.

But back to the original issue, one thing I forgot to mention is that I do have to put anti-fouling paint on the prop anyway to make sure that it doesn't grow fuzzies - which will really slow me down and reduce drive.

As for plan C, Ed, without getting in the water each time I take out and put away the boat (twice per sail), I have no way to put a bag around the lower unit so that the bag remains always above the water line. In a way, the paint becomes a permanent bag. Keep in mind that once I get Solsken in the water, I want to maximize the time available on the water and minimize the time getting the boat ready to go and putting it away. I am not part of the racing crowd.

[ebb]

Theis,
Have been one to point out the expediency of keeping the horse
harnessed to the cart at all times when in the barn.

That is a great tip.
Now it's obvious that the french fitted zinc hiding under the cavitation plate has to be carefully connected electrically to be a working anode.
And I have written that into my Yamaha Manual. Thanks.

Would be wonderful if that alone solved your terrible corrosion problem!