Had what we thought was a healthy boat. a 1987 Sumerset. had the aluminum bottom visually inspected out of the water(by a professional) with no evidence of corrosion noticed before we bought it. recentl noticed a slight increase in bilge pump activation and found a loose line to the drain but also noticed a small hole in the hull about the size of a pencil lead in the vicinity of the bilge pump. its on a flat surface and I would say is due to corrosion. it's not near a _frame_ or stringer. has me really concerned . Any advice as to how to repair. More importantly am I looking at a serious ongoing problem.

thanks

That is strange, is it close to the area where the travel lift straps would be? I have heard of something being on a strap, such as a screw doing this.it is also possible a weld went south but very doubtful. How long have you had the boat? You can for a temporary fix put a screw in the hole with boatlife above and below caulk on it. It will stop the leak.You can then wait till you are ready to pull it again.If you have been where you are long, it is possible reverse polarity could have done it, again doubtful.

Thanks for response. I've looked a little closer at the situation and I just don't believe I have a large scale corrosion problem as all of what I can closely inspect appears in good condition. Ive owned the boat 1 year and it's allways been a pretty dry boat although the area in question typically has an inch or two of water.(just forward of bulk head seperating engine compartment from rest of hull)

I'm not real smart on electrolysis or reverse polarity but I noticed this: Some one had attached a small l pump to a crossmember into which the airconditioning condensation was piped. When the float level increases the pump activated and emptied itself overboard. Apparently, the two low voltage wires which served as the float level circuit, were connected by wirenuts and the connection was sometimes submerged in the shallow bilge water. The small pin whole is directly below where these wires would have been.(I've relocated them.) Is it possible that could be the cause?


merlin38942.32125

That could do it over a long period of time. Just put the screw in with the caulk and permanently repair on haulout.This fix will last for years.

Well, you found the problem. Galvanic corrosion is the correct name for what you called electrolysis. DC is the main driver for what is also called stray current corrosion and is usually caused by introduction of electrical currents into the water around or in the boat. By the way, your aluminum hull is an excellent conductor so I would check the outside too, the next time you have it out of the water. You need to get those wires and any other exposed electrical contacts out of the water, or coat everthing with silicon sealant to keep the water away from it.

Anymore news on the corrosion problem. It is interesting. i told OHB that that would happen , I believe he had seen it alspo. You are right that is the proper term

OHB, Have you done anymore research on the grade of aluminum for Saltwater? Coast Guard is having problems with alum boats. Burger, and Broward are apparently not having the same. There has to be a reason.