Pitting and corrosion in fresh water. 5.0mpi/ alpha 1

[nauticool]

Hi, Have a 5.0mpi 2005 and alpha one outdrive 1990.
Just lifted today to find some serious corrosion to outdrive and propeller.
Boat is left in fresh water river but is taken out to sea on a regular basis.
When i bought the boat 2 years ago it was sat in salt water so is obviously set up for that.
What anodes should i change to? is there a type for both fresh and salt water?
bonding seems to be ok, whats the best way to check?
Note; there is no shore power or mains connected to boat at any time

Many thanks

 

[Bondo]

Re: Pitting and corrosion in fresh water. 5.0mpi/ alpha 1

Ayuh,... Sounds like ya have a serious electrical Issue aboard,....
Bad grounds, or Bad bonding, or Bad connections somewhere...
Maybe look inta adding a Mercathode or something....

I hear aluminum or zinc in the brine, 'n aluminum or magnesium for sweetwater...

Mine, for some reason always look like new...
Except for the time I hooked up lights, 'n grounded 'em through the hull of my tinbarge...
Both the anodes, 'n the hull almost turned to dust, in a Short time....
Didn't like them lights, anyways,...

 

[TilliamWe]

Re: Pitting and corrosion in fresh water. 5.0mpi/ alpha 1

There is a "Freshwater Only" anode kit for your drive, that's what you need. It's twice as expensive as the others. Even if you don't have shorepower, what about the rest of the dock and your neighbors? Stray current can be a real issue.

 

[nauticool]

Re: Pitting and corrosion in fresh water. 5.0mpi/ alpha 1

No-one has shorepower in a 2 mile radius. Im on a fresh water river about 3 miles or more from the sea, Christchurch (England).

The only problem with freshwater only anodes is that they will get eaten when i go out to sea and im guessing will offer no protection?

will look further into the bonding and see what local dealer recommends

 

[TilliamWe]

Re: Pitting and corrosion in fresh water. 5.0mpi/ alpha 1

They don't get eaten in saltwater in a matter of hours. You just can't store your boat in salt or brackish water with them. If you truly are slipped in FRESH water, you need "freshwater only" anodes.