Calculating the Torque required for Rudder

[David Hope]

I need to know the torque required to operate the rudder's (2) on my boat. It is a Cheoy Lee 66LR (45 ton's, cruise at 10 knots). Rudder size is approx 42"H x 24"W. I've gone on line and reviewed the formulas to determine the max torque required but am looking for verification. I've included a pic: This is not my boat but I have the same layout. I'm considering going to electric drive but am still researching. General thoughts on max time required from center line to port/starboard would also be appreciated. I"m upgrading the controls and will be able to tie the auto pilots signal to the electric drive unit if I decide to go this route.