I'd still like to know whether or not it's a non-geared folding prop... It's the most likely cause of an alarming amount of vibration that is likely to 'come and go'.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)