All of my thur hulls with valves below the water line have fiberglass built up like a pyramid around them are all Morgan's in that eara built that way ,how are you suppose to inspect them for corrosion ,thanks
I'm sure it has been done and think there has been posts on here regarding replscement. I will need to give Sonata's some love next time we haul out. Several valves are almost impossible to turn. Not sure how the thru hulls are either.
Sorry I am not more help,
It's A pretty quick job with a grinder. The hardest part was reaching in behind the engine because I'm fat. Mine didn't have that big mound of fiberglass like some do. Whenever I have the boat hauled for paint I change out something. Now everything below the waterline is new
For years it annoyed me that to access the engine thru hull, the port cockpit locker had to be completely emptied, then I had to contort myself into the locker to reach the valve. Two years ago the valve was relocated into the engine compartment just to the port side of the water lift muffler. Now it in easy to reach from the rectangle hatch in the quarterberth and can be inspected and serviced quickly. The photo shows a 1/2" fiberglass pad bonded to the hull and the 3/4" marelon valve with a bronze thru hull fitting. All the thru hull valves on Dana are Marelon for years and all have performed successfully.