Dis-similar metals?

[Gallivanters]

I enjoy hearing sea-stories about the catastrophic failures and end results of using dis-similar metals on our boats.

Have any to share?

My own personal eye-opener came after we'd destroyed our mainsail on the first day of an Atlantic crossing - due to an un-controlled gybe. We limped into the harbour of refuge on the most remote of the Canary Islands to bend on our old main, which was burried in the guts of the lazarette. When I pulled the sail out of the bag - I discovered a triangular shaped stain of silicone goo and white chalk where the aluminum headboard should have been. All that I could identify of the original headboard was a stainless steel gromet and several brass tacks which had apparently been used to attach the assembly to the sail. And we still had 2800 miles to go...

Aluminum, Stainless Steel & Brass moistened by seawater - I probably could've powered an anchor light from the electrolic current being generated there!

I fixed the problem as best I could with a piece of plywood I found on the dock by cutting two pieces to shape and stitching them onto the sail with heavy twine. It worked good enough.

Our old anchor windlass failed in a most spectacularl way - but I'll save that to share later.

Kirk

[Bedouin]

Silicone glue, as in 'instant gasket' has a reaction with aluminium and brass. I used silicone instant gasket to use on my Yanmar water pump after replacing the impellor. The cover is held on with 6 brass screws. Two months later the bilge was full of water and the flow in the exhaust had stopped. The screws has completely eaten away and the cover fallen off. It could have been a very expensive lesson!!

Regards

Peter:0)