Sloppy Rudder Control Horns

Published date: December 11, 2011
  • Boat Type: Boat Type

I've made a number of small modifications to the rudder control of my 26M to help remove slop from the control system. This is one that I've actually measured - The control arm inside the hull of the 26M attaches to the rudder horn via a single cross bolt, this bolt is factory drilled with a rather sloppy hole, and it may even grow larger as the boat ages.

When I had these parts out of the boat, I decided to jig them up and measure the movement - with no pressure at all (except relieving gravity) I measured over 250 thousandths of in an inch movement of the control arm (at the crossbar attachment) when the rudder horn was synched solid in the vise. I decided to drill and tap the rudder horn and precision dill the control arm for a shank bolt. I used an aircraft bolt, AN3-5A which has a sheer strength of 75ksi. This simple mod will move all the shear load to this point, but the large cross bolt would still be there for safety - though I doubt I'll bend the AN3 bolts. (Inspection after several trips has indicated no visible signs of wear on the smooth shank or threads)

After the modification you can not detect any movement between the rudder horn and control arm, I jigged it up on the vise and measured it gain with my dial indicator - if I push in both direction, the max defection hit about 16 thousandths of an inch. A substantial improvement.

Chris.

Published by: u12fly


Model Year: 2006
Photo Caption: The stock configuration allowed over 250 thousandths of movement

After modification the movement is reduced to about 16 thousandths

The rudder horn is drilled and tapped, the control arm has a close tol hole

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