I would like to hear your opinions regarding options for a coupling between my rudder
To provide some background I have a 38' steel ketch
with a full-length skeg-hung rudder. The shoe at the bottom of the skeg is welded on permanently and not removable. This rules out having a permanently fixed shaft in the rudder, and I like the option to remove the rudder for service
without leaving an empty hole in the bottom.
coupling is a simple four bolt flange that connects the shaft to a matching flange at the top of the rudder. This allows the shaft to be inserted into boat, then the rudder to be inserted into the shoe and rotated up to mate with the shaft flange.
My concern is that if the rudder should be struck by something at speed, there is the potential that the coupling bolts could shear off, and the rudder could fall free. This would leave me with NO rudder, which I would not like to contemplate.
On my last boat, a Franz Maas Calypso 43, the rudder shaft was tapered and keyed like a prop shaft, and mated with a tapered and broached hub welded into the rudder. this way, even if the shaft key failed, at the worst the rudder would be useless for steering
, but would still stay connected to the boat by the shaft. The worry I have with this arrangement is that the current
shaft log is sized for 1.25" shaft, and the maximum contact surface that I would be able to get for the hub would only be about 3.5" long. That would be a LOT of twist force to excert on a very short area of contact.
Any ideas, suggestions, or insights you would have will be very welcome.