Help! No Anodes

[Jabs]

I have just hauled my Contessa, 1972, for the first time as owner.

I was rather surprised to find that she has no anodes.

I just came back from polishing the prop and find it has distinct pink blotches...

I haven't looked at skin fittings yet.

Whilst everything has run well for many many years, I am tempted to fit an anode, ground it to the engine and ground all the skin fittings back to the engine.

Or am I creating a lot of work that may or may not be essential??

Thanks

Tony.

 

[Simondjuk]

There is no need to ground skin fittings since they are, on your GRP boat at least, isolated from the electical circuits.

An anode to protect the stern gear would be advisable however.

 

[VicS]

As above do not connect the skin fittings to anything.
If they are bronze or DZR brass then they will be fine as they are. If they are not and show any sign of dezincification then change then for fittings that are.

If the pink patches on the prop are any more than surface deep then a hull anode bonded to the engine / gearbox would be a good idea, but remember the flexible coupling will need to be bridged to complete the circuit.

Because a good continuity is not always obtained through the gear box bearings etc a shaft anode might be more sensible than a hull anode if you can fit one.

If the pink patches are only surface effects do not worry ... you would trying to fix something that in 40 years does not seem to be a problem.

If you have a shorepower installation and tend to leave it plugged in, even if not actually in use, ensure that you have a galvanic isolator fitted, unless the shorepower earth is not bonded to the DC negative)

 

[rob2]

If the prop is the original, then, anode or not, it's entitled to have a few pink blotches by now. As th function of an anode is to form a wet cell, just like in a lead/acid battery, it needs to be within line-of-sight of the item to be protected. In fact, the closer the better as the seawater which is the electrolyte in this arrangement will then have a shorter conducting path.

As is stands, the bronze prop on a stainless shaft is the pair which are currently forming a cell. There is no metal close enough to the skin fittings for them to form a pair, so connecting them will have little or no effect. If you fit an anode, you should check the resistance from the anode to the prop to ensure it will be effective. It should be only a few ohms. Sometimes a flexible coupling can be an insulator between the two, so it has to be bridged with a flexible braid. Alternatively, a brush can be fitted to connect to the propshaft.

An anode is often uneccessary if the boat is on a swinging mooring and therefore does not have shore power or metal piling close by with the added possibility of stray earth currents from other boats' installations.

Rob.

 

[NUTMEG]

Snap

I posted a very similar question last year upon lifting my W21. No anodes and pink patches on the prop just as you describe. She is 30 odd years old and the consensus was to leave well alone. She is not the only W21 to have no anode, apart from the pencil one in the engine.

Worry about something else!