Anode bonding.

[WayneS]

I know that this has probably been asked a million times but a quick search did not find the answer.

We have a GRP boat in a marina, with hydraulic drive turning a s/s shaft and a Gori folding prob.

We seldom use shore power but may start to use it more this year.

Currently we only have a shaft anode.

I am not sure if there is electrical connectivity between the engine and the shaft .If there is it will be via the internal braiding of the hydraulic oil pipes.

Our last anode lasted 2 years but was almost totally eroded away (Did not take the boat out of the water last year so not sure what it was like after 1 year)

Can anyone tell me if it is necc for me to electrically bond the shaft to the engine esp as we may hook up to shore power this season and have a perm connected battery charger.

Cheers

W

 

[boatmike]

The shaft anode is the best means of protecting a propeller. Dont worry that it has eroded away. It's supposed to. Just replace it. No need to bond shaft to engine. Your engine probably has an internal anode though. This should be replaced annually too. If your through hull fittings (engine intake etc) are bronze and sound there is no need to do any more. Shore power hook up should not affect you if your battery charger is properly earthed as it should be. The HT Earth should be a separate earthing plate on the hull. You can use an anode if you like but make sure its not connected to anything else. You should also have a residual current circuit breaker (RCCB) in the circuit. Preferably between the shore supply input and the battery charger.

 

[VicS]

You may well find the "Electrics Course Notes" in the Reading College boat maitenance course worth reading.

http://www.reading-college.ac.uk/marine/

Look at the section on Mains Electricity if you are planning to use shore power.

 

[Piers]

Anodes are sacrificial. They get eaten before expensive engine / shaft / prop parts. Hence, if your shaft anode was eaten, replace it!

Your engine will have an anode(s). Keep them up to speed - ie., never more than 50% eroded.

Remember, anodes are there to protect your investment.

Talk with these people. very helpful - M G Duff - they may well also recommend bonding your engine to the shaft.