Prop corrosion

[Nudge]

There does seem to be a lot of it about!!

My Maxprop has corroded beyond repair last season so a Kiwiprop is on it's way... Issue is almost certainly electrical. Have found a couple of things, but also had some conflicting advice.

Found that the alternator grounding was suspect so have fitted a new earth strap and replaced a dodgy isolating earth switch. Galvanic Isolator now fitted too although I don't use shore power very often so if any stray currents are involved it is likely to be 12v system.

One point that I am seeking views on... The GI supplier suggests that all skin fittings, prop, tanks, keel etc should be bonded to the GI earthing. Another knowledgable and well respected advisor suggests that the prop and shaft should be isolated from the engine.

Help!!

Nudge

 

[Mrnotming]

Big subject!
1.what material is your hull made of? ( more materials than GRP)
2. Is there a great lump of earthed metal near your berth(Marina Piling)?
3.Seawater immersion?

The real experts will be along shortly!

 

[GrahamM376]

If it's a grp boat, consensus seems to be not to bond skin fittings or keel. Bonded keels seem to suffer more rust problems than unbonded and skin fittings are electrically isolated anyway. As far as shaft and prop are concerned, my engine is connected to my main anode, there's a bridging wire across the flexible coupling, there's an anode on the shaft and another on the Featherstream. Done it this way on 4 boats over 18 years and never had a problem.