I heard of one case with a new Japanese built car carrier, where the rudder and stock dropped and it was found that the ship had been built without a Pallister bearing!! Nothing to support the weight of the rudder at all.
Generally check out the condition of the Rudder bearings and the ship's framework below the Rudder.
Good Luck and let us know what you found.
It is always better to ask a stupid question than to do a stupid thing.