To link or not to Link?

[owendo]

What is the general opinion..

On a Wooden Yacht (East Anglian) new galvanised floors have been fitted this year. Should they be linked to-gether and then linked to the sacrificial anode?



Mike Woodhouse
Vertue V17

 

[ccscott49]

What are they fastened with? I would link them all and link them to the anode.

 

[ianwright]

On a wooden boat use an anode only to SOLVE a problem..
I have a very small zink disk on the bronze rudder shoe for example. Never bond the metal bits on a wooden boat, chances are it will produce problems rather than prevent them.
IanW

Vertue 203, Patience

 

[mickshep]

Dear Mike. My 1946 5 tonner was built with galved floors, copper rivetted through the teak frames and planking. never bonded to an anode till late 80,s as floors starting to show wastage, within a few years the floors needed to be replaced anyway, but timber effected by alkalie salts beneath steel meant urgent work required, It was interesting to note that only the only ribs to be effected were those beneath the floors that had been connected to the anode I was told this was direct result of bonding to an anode. Have since been told to not have anodes connected as the metal might be protected but the timber is gradually destroyed. I figure a new prop or stern tube, (not needed yet after nearly 57 years) will be a lot easier (and cheaper) to replace than a new teak stern post. Apparently where the amount of noble metal (in this case the copper of the 0.5" rivets) is considerably less than the steel, one tends to balance out the other so little or no electrolytic action takes place. Hope this helps, Fair winds, Mike

 

[Mirelle]

Absolutely

I agree precisely with that. My original (Kelvin) sterntube, shaft and A bracket are starting to show some signs of wear and will probably need to be replaced when I get round to replacing the 35 year old Volvo - but the sterngear is 65!

I also have a horror of stray currents - and if you bond you make life much easier for stray currents.

 

[charles_reed]

There are two diametrically opposed schools of thought here.

The more didactic demand everything be bonded together and just shrug when you get wastage.

The more pragmatic reckon if you have everything insulated you've got nowhere for stray currents to go.

I'd tend towards the second view especially on a wooden boat.

However when you have radar, SSB and need for a sound RF return you've got no option but to set up the anodic ring.
My 8-year old 316 prop shaft had considerable evidence of anaerobic corrosion when I replaced it last year - and that was with shaft, prop and twin hull anodes bonded onto the ring.
With RF ground, surface area is infinitely more important than cross-sectional area.