Galvanic corrosion - picture

[enn858]

Hi

I have found this picture of some severe corrosion on 2 mercruiser (bravo ?) drives

Does anyone know the history behind this case? i cannot remember where the picture came from (had it on my hdd for years) but it was from some boating forum

 

[Don S]

Re: Galvanic corrosion - picture

I've seen a few like that. Dock wiring or battery cables with cracked insallation laying in water in the bilge with a battery charger plugged into shore power to make sure the battery doesn't go dead.

 

[enn858]

Re: Galvanic corrosion - picture

Would this hapen in weeks or month? i would guess that the anodes would disapear fast if it had cracked cables and shore power - but would it be possible for the drives to become this destroyed in eg 3 weeks?

I check my anodes every app 3 weeks and try to follow the speed they disapear - but normaly they last 3+ years on my boat (it has no shore power and a checked and functioning merchatode system)

 

[abj87]

Re: Galvanic corrosion - picture

It would take one hell of a current leak to do it in three weeks. This is nothing that I would be concerned with unless you are docked next to boats with shotty wireing.

 

[dan t.]

Re: Galvanic corrosion - picture

looks like a very neglected boat in salt water,likley no anodes left, early bravo 3s supposidly had bad corrosion problems (power boat reports magasine)

 

[Dunaruna]

Re: Galvanic corrosion - picture

I have seen a pair of 45ft alloy toons destroyed in 4 weeks due to stray (leaking) shore current. BTW, this is called electrolysis, not galvanic corrosion.

Galvanic corrosion does not involve an external power source, electrolysis does. Same visual damage although electrolysis can be much more destructive if not kept in check.

 

[gman90706]

Re: Galvanic corrosion - picture

....and I thought I had corrosion problems

 

[TilliamWe]

Re: Galvanic corrosion - picture

early bravo 3s supposidly had bad corrosion problems

A lot more than the early ones had problems. But this picture above is not a Bravo 3 and is not the fault (totally) of Mercruiser. Obviously there is/was a severe wiring problem somewhere in that boat or at the dock. And obviously it went a long period of time before it was checked.
This photo is not representative of "normal" corrosion that one would see.

Good point on that one being "electrolysis" as opposed to galvanic corrosion. Most people interchange the terms, but it's not correct to do so. While neither is desirable, electrolysis is more easily prevented by checking boat/dock wiring. Sometimes galvanic corrosion just happens (like on Bravo 3s, or all current Volvo Pentas.)