I have a 1979 CT 41 ketch
......classic, full keel
. Have owned it for five years. Love it.
From the very beginning, there has always been a rattling/tapping/vibration sound coming from underneath when the engine
is running.......best guess is sound is emanating from the shaft tube.
For unrelated reasons, we have been through two engines, three shafts, and three propellors on this boat. With each change the pitch/inensity of the noise
changes, but it never goes away.
only occurs under way under power. Not sail. More importantly, (I think) it does NOT occur if we run the engine
in the slip. In gear
I don't think it's the rudder
, as my husband has crawled inside and held the rudder
post while this is going on. No vibration of any kind there.
Cutlass bearing has a clean bill of health
from the shipyard.
I'm thinking we pull the shaft next haulout and take a look-see up the tube. Take the shaft to the shop to check for straightness (even though we had this problem with previous shafts that were known to be straight).
New engine is quiet (Yanmar 4JH3-TE). Hate ruining it with this cockpit