Rudder stock sacrificial connection

[AllanG]

When nosing around my Nimbus 320c steering system yesterday, I noticed a jubilee clip clamped to my rudder stock, and around the clip were several coils of copper wire.

Looking closer, I found a copper wire leading from my hull anode mounting bolts to the location of the rudder stock, but not connected to anything.

It's my guess that this wire was originally connected to the rudder stock, but at sometime in the past it broke.

However, before I reconnect the wire, can anyone confirm if the rudder stock on a Nimbus 320c should be connected to the hull anode circuit?

Many thanks, Allan

 

[omega2]

It cannot do any harm to reconnect it, must have been put there for some reason in the past, has the boat always been yours? and have you had a lift out recently to see if you still have a rudder??

 

[AllanG]

I bought the boat last October, but before it was relaunched after the survey, the rudder was removed to replace the propeller shaft cutless bearing so, perhaps, the guys that did this job forgot to reconnect the wire.

The rudder was certainly in place last weekend when we went out on the boat!!

 

[andy59]

I have just been checking through all my bonding cables and all off the sterngear / p brackets / shaft seals are all connected to the main hull annodes ( F 36 )

 

[PaulGooch]

My bonding circuit also includes shaft, P bracket and rudder stock.

 

[superheat6k]

Bonding circuit

Your zinc anodes will only protect the underwater metal fittings they are electrically connected to - hence the bonding wiring. Over time copper will work harden and break, and Winter haul out is the ideal time to check continuity between the anodes and the underwater metallic parts.

On my boat recently I had to remove a seized seacock. Good job I did because when I was undoing it the thing disintegrated - de-zincification of the brass body. This had not been bonded.

Galvanic corrosion can affect a wide range of metals, even the best bronzes, so hooking these all up to your anodes can only be beneficial.

 

[VicS]

Your zinc anodes will only protect the underwater metal fittings they are electrically connected to - hence the bonding wiring. Over time copper will work harden and break, and Winter haul out is the ideal time to check continuity between the anodes and the underwater metallic parts.

On my boat recently I had to remove a seized seacock. Good job I did because when I was undoing it the thing disintegrated - de-zincification of the brass body. This had not been bonded.

Galvanic corrosion can affect a wide range of metals, even the best bronzes, so hooking these all up to your anodes can only be beneficial.

Not so

Dont use brass except dezincification resistant (DZR) brass below the water line.

Bronze, gunmetal and DZR should not need protection from anodes.

In fact one of the recommendations made by in the MAIB Report on the near loss of the FV "Random Harvest" (q.v.) a few years ago was that the through hulls should not be connected to the anode system. That was a contributing factor to the incident!