Which anodes in tidal Thames marinas?

[nmeyrick]

My boat is currently out of the water, and will shortly be going back in and berthed at St Kats, so off the tidal Thames but in a locked basin. The boat will be moored most of the time, but will go out to sea for a couple of weeks a year.

After looking into anodes the impression that I get is that Zinc sea water anodes are little use in fresh water, while magnesium anodes are liable to fizz away if I head out to see. What I'm not quite sure on though, is how fresh or salty the water there is, having never been tempted to taste it. I presume it will be brackish, which would suit aluminium, but would the water be salty enough to work with these or would aluminium be more suitable?

What do people in similar marinas use?

Any comments much appreciated

Thanks
Neil

 

[byron]

I always used Fresh Water anodes and never suffered a moments problem. The water in say St Kats is not salty, indeed fresh water fish abound there. By the time the tide has pushed up as far as say Greenwich it is pushing so much fresh water before it that it is only brackish.