Tubeworm / Anode Material

[Ammonite]

For this season I changed the hull anode from zinc to aluminium and its now covered in tubeworms about 2" to 3" long and the diameter of a pencil. Arguments about whether you need a hull anode or not aside (although this could be evidence that its not doing anything but then again why would zinc be any different) has anyone experienced something similar. The boat is based in Portsmouth Harbour and the hull is coppercoated. There's no tubeworm growth apart from on the hull anode and no sign last year when using a zinc anode. I switched material because volvo no longer supply zinc anodes for the saildrive. Thanks

 

[Snowgoose-1]

I think nearly all anodes are mainly aluminium now because of the cost of zinc. It would be nice if the makers could publish the percentages.

 

[mjcp]

Mine are zinc, west coast of Scotland. no worms on the anodes (x3), but there some on the stainless of the shaft most years.


(I do not have anything made of ali under the waterline)

 

[alahol2]

Mine are zinc (to some kind of standard quoted by the manufacturer). No tube worm on the zinc but a few tiny ones on the studs usually.

 

[vyv_cox]

Tubeworm does seem to have metal preferences. It is noticeable that my stainless steel shaft and rope cutter have a good crop of them whereas my zinc anodes have very little.

 

[SaltIre]

Tubeworm does seem to have metal preferences. It is noticeable that my stainless steel shaft and rope cutter have a good crop of them whereas my zinc anodes have very little.

Have you regurgitated the anchor you swallowed and bought another boat?

 

[Ammonite]

I've answered my own question, or at least MG Duff have. Zinc anodes contain cadmium which keeps the tubeworm off. Aluminium anodes don't. It sounds like it's only a problem where the anode isn't doing a great deal (and where you are based)

 

[vyv_cox]

Have you regurgitated the anchor you swallowed and bought another boat?

No, boating is finished for us. Still have hundreds of photos though.