Hi when replacing the prop shaft and dripless seal on my LM27 I noted that the stern tube had turned a cherry red colour. I suspect that some dezincification has taken place and I am looking to change it. It is a 36mm outside diameter with the prop shaft being 25mm. There doesn't appear to be any securing bolts either outboard or inboard so I am unsure if it screws in from inside. There are no bolts on the cutlass bearing housing and the bearing appears to butt up to the tube. Does anyone have any advice other than get a professional.