Hunter 34 Aft Keel Bolt / backing plate (?) corrosion

[c07chrisjohnson]

Aloha everyone,

I bought a 1985 Hunter 34 in September of 2019 and just noticed a lot of corrosion on the aft keel bolt. Previously it was not corroded at all and looked great. I thought it was coming from the stuffing box, as it looked like there was evidence of a leak running down below the motor into the aft keel area, but I cleaned the bolt & plate recently and noticed that it's salty again, there also looks to be bubbles of salt seeping in from the side/bottom of the backing plate.

I attached some pictures for reference.

Has anyone seen this before, is it possible to have water seep in from the bottom of the backing plates? Also, can this be fixed with a new backing plate and nut provided the bolt isn't corroded to the plate, can the bolt be replaced if need be?

Thanks,

Chris

 

[Benny17441]

Yes, yes and yes. Was the boat hauled out for a surveyors inspection of the hull bottom when the boat was purchased? Any anomalies observed at the keel/hull joint should be noted on the report. Really the bolt looks in good shape for a 35 year old boat; that don't look like rust but more like crusting. Before you go attempting to remove the bolts go trace all the water intrusions into the bilge as the water as water seepage does not have to be necessarily from the bolt. Usually minor leaks through the Keel/hull joint are taken care by retorquing the nuts on the bolts. I believe the torque specifications is to 90 foot/pounds or like they say until the fiberglass creaks. You can rent or borrow an capable torque wrench and test the torque settings of each of the bolts. They should all test closely to the same value. You could remove the nut to inspect some of the bolt threads below but if you do replace the nut with a new one. Usually water seepage into the bolts of a iron keel will ooze a rust stain and find the bolts somewhat loose. Like I said from the photo I do not see a problem.

 

[c07chrisjohnson]

Yes, it was hauled out, no anomalies were reported, it used to look really good, more like the picture I posted below. It's almost like parts of the affected plate disappeared, maybe galvanic corrosion?