www.svbeatrix.com — The website of the Sailing Vessel Beatrix, Kelly-Peterson 44 #276 (1980).

This data was gathered by putting an automotive torque wrench on the steering wheel nut.  "Spokes" were translated to degrees of wheel turn and rudder angles.  The data were used in sizing an hydraulic-electric autopilot actuator.

Wheel to Rudder Turn Ratio 11
Rudder Quadrant Degrees 90
Steering Wheel Diameter 30
Speed during test (knots) 6
Hull Speed Correction 1.927469
AT 6 KNOTS AT HULL SPEED
6-Spoke Wheel Turns Wheel Degrees Rudder Angle in Degrees Measured Wheel Torque in Ft-Lb Rudder Post Torque Ft-Lb 10" Tiller (pounds) 7" Tiller (pounds) Rudder Post Torque Ft-Lb 10" Tiller (pounds) 7" Tiller (pounds)
1 turn  2.25  spokes 495 45.0 78 858 1030 1471 1654 1985 2835 Factory Hard Over Limit
1 turn  1.79  spokes 468 42.5              
1 turn  1.33  spokes 440 40.0              
1 turn  0.88  spokes 413 37.5 50 550 660 943 1060 1272 1817 New Hard Over Limit
1 turn  0.42  spokes 385 35.0              
5.96  spokes 358 32.5              
5.5  spokes 330 30.0 40 440 528 754 848 1018 1454
5.04  spokes 303 27.5              
4.58  spokes 275 25.0              
4.13  spokes 248 22.5              
3.67  spokes 220 20.0 30 330 396 566 636 763 1090
3.21  spokes 193 17.5              
2.75  spokes 165 15.0              
2.29  spokes 138 12.5              
1.83  spokes 110 10.0 10 110 132 189 212 254 363
1.38  spokes 83 7.5              
0.92  spokes 55 5.0              
0.46  spokes 28 2.5              
0  spokes 0 0.0 0 0 0 0 0 0 0





Disclaimer
The contents of this page are an example of a refitting job performed on a single vessel by its owner.  Just because I put it here for your interest and information does not guarantee it will work on your boat, or work at all. Fair winds & smooth sailing. -- Jeff Stander

 


Last modified: February 18 2017 15:43