Wood burn around swim platform supports

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Wood burn around swim platform supports

Postby Rod Graff » Fri Jan 11, 2019 1:16 pm

We have an old 32 Woody here. I have been disconnecting various thru hulls from the bonding system due to deterioration and salt formation around the fittings. I see I am getting the same now around the swim step brackets and their mounting bolts, and also the fitting where the exhaust hose passes thru the transom. I neutralize the deposits with vinegar, flush with water, but the deposits return. Should I disconnect the bonding to the swim step brackets? I have a set of ZINC-2 plates sanwitched on the bronze rudder, and a 1 1/2” close clearance zinc on the shaft space between the stern bearing housing and prop. Those are my only zincs so I do not think I’m over zinc’d. There is a shaft brush, and a pigtail on the rudder shaft, that tie everything together. The shaft is Stainless steel. I know there are a lot of different opinions on bonding a wooden boat.
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Rod Graff
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Re: Wood burn around swim platform supports

Postby bpbyrne » Sun Jan 27, 2019 11:40 am

As you have clearly found, there are some wildly varying oppinions out there. On my '70 woodie, i identified wood burn around shaft logs, and a few areas of the bonding system itself. I read all the contrasting oppinions and decided not to risk pulling the bonding. Instead, I took the areas of worst burn and cleaned, and cpes impregnated them. I check regularly and have not seen and recurrence over 18 months. That being said, obviously the burn came from somewhere and the above wont have changed that. I believe this burning happened over a long time in "never inspected" parts of the boat. At last haul, no burning was found on the outside. I removed a zinc or two as i suspect previous owners were a little over enthusiastic there. I was also advised (but have not yet completed) to measure the current flow in the boat. Effectively you are lookkng for electrical leaks into the boat, bonding, water etc. Certainly i had some terrible wiring when i got her that has since been addressed. I know for sure the 12v cabin lighting was grounding occasionally.

Hopefully this non scientific but first hand experience helps you somewhat!
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