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Galvanic action around corners?

I have a flat bottomed steel riverboat boat in freshwater & use magnesium anodes for sacrificial protection. I put some extra anodes on the baseplate of the boat because if mounted on the vertical sides they would quickly get knocked off. However someone has told me that galvanic action (including protection) can only work on line-of-sight and not around corners. Is this true?

Michael Bonin
I live on my boat - London UK
2006

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No, it's not true, Michael.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2006

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First of two simultaneous responses --

It is the conductivity, I believe your protector to be as nearer as possible to corroded area.
Good luck.

Khair Shishani
aircraft maintenance - Al Ain, UAE
2006

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Second of two simultaneous responses --

So the anodic/cathodic potential difference is still in effect and the sides of the boat will be protected, even though the anodes are positioned on the bottom around a 90 degree corner and not within line-of-sight?

MICHAEL BONIN
- London, UK
2006

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Cair is correct that you'd always like anodes as close as practical to the areas of concern (and several anodes if possible). But line-of-sight has nothing to do with it (as far as I know -- just an opinion, and not from a marine surveyor).

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2006

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2006

I found some line-of-sight references on the internet in relation to electroplating which also uses a galvanic/electrolysis process:

http://www.enthone.com/resources_detail.aspx?Page=characc.ascx

However, it also talked about line-of-sight dependent and non-dependent processes but I'm not sure which anodic protection of steel is?

MICHAEL BONIN
- London, UK