Electrolysis of propellor.

[Colin F]

Can anyone recommend a specialist located on the West coast of Scotland that can carry out current leakage tests.

 

[coreng]

Can anyone recommend a specialist located on the West coast of Scotland that can carry out current leakage tests.

Corrosion of propeller due to electrolysis is due to an outgoing electric current that can easily be checked through potential measurement vs Ag/AgCl electrode. This will tell also efficiency of anodes. Shift in various configurations measurements will indicate a stray current. Though not common yet with recreationnal boats, you can (should) do this by yourself as it is an easy regular and best practice control process.

 

[nedmin]

Some years ago I was effected by electrolysis,took the boat out one winter and the propeller was turning pink.put a milliamp meter between propshaft and gearbox and got a fairish reading,boat in water when taken,cant remember what it was but I know I was surprised at the time.the engine etc was properly earthed but obviously the prop wasn't. It was because the oil in the gearbox bearings was insulating the prop from the boat earth.I made a brush holder out of an old Black and Decker drill,mounted it on the end of the g/box and used the gearbox coupling as a slip ring.connected brush to boat earth.Never had any problem since, If you do this mod. you want to use a starter motor brush as they have a high copper content so will be a lower resistance.

 

[vyv_cox]

The OP started a second thread on the same subject. I replied to it and he PM'd me. Apparently it is an aluminium prop, hence my response on the other thread.