This was the original 1/2" stainless stern lifting eye - 1976. From the outside it looked perfect. It took less than 5 ft-lbs to twist off both sides.
When I got it out, it was clear that it had spread about 5 degrees so it had already failed under lifting load. The thin little stainless backing plate was stretched out - it had caught the threads and was the only thing that kept it from coming out the transom. As far as I know, it was never overloaded and the fractures looked like they were from corrosion rather than simple stress. The other side 'looks' fine, even after I removed it - no apparent deep corrosion and only a little surface rust on the threads. I don't have access to xyglo or magnaflux inspection stuff any more so I have to rely on visual. I don't trust any of the lifting hardware now. I remember why I like slings too.
So what is the right replacement here? I'm thinking 316L for better corrosion resistance? The bow eye and lifting hardware - especially that threaded rod -gets added to the list too.