Protection of seacocks & skin fittings with anodes

[dougln]

I have a GRP yacht with a volvo sail drive. The only sacrificial anode below the water line is the one fitted on the sail drive in front of the prop. There is no other tear-drop or other style anode bolted through the hull. As a result I am concerned about corosion within the seacocks that I assume are a combination of different metals. My question is - do I need to install a through hull anode and bond it to each seacock and the engine, or am I ok without one?

I have only had the yacht a year (although it is 20 years old) and am not aware of a any earlier problems. Although I did replace all the seacocks when I bought the yacht as part of an overhall.

I would like to hear if anyone else has a similar set-up or any recommendations.

Thanks in advance.

 

[VicS]

If you replaced the seacocks with decent bronze ones they should not need any protection. If you have any doubts or they have pinkish appearance where in contact with the water they you have two options. Either replace them with bronze, or at least dezincification resistant (dzr) brass, OR fit anode(s).

Anode(s) should be reasonably close to the fittings they are intended to protect and not shielded from them. Bond the anodes to the fittings internally. Each anode should be bonded to the fitting(s) it is to protect. It is not necessay to bond them to the engine (or to each other) .

Don't bother if you see no reason to fit them but reassess the situation every year.

The boat I shall be on all next week is getting on towards 30 years old has the original seacocks and no anodes.