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.


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


Useful information

  • Perform modifications at your own risk
  • Fully research modifications before performing yourself
  • All mods are listed as is with no waranty
  • This site does not make any claims about the validity or safety of modifications posted.

Related Mods

  • Drainage Holes
    Drainage Holes
    Miscellaneous - - December 1, 2019

    Here you can see the new lower drainage holes I drilled in the battery and gas compartments. The caulking in the compartment also needed to be redone since it had a few leaks which brought water and gas into the space between the inner and outer shel...

  • Boat Cover
    Boat Cover
    Miscellaneous - - December 1, 2019

    The full boat cover protects the boat against the harsh Australian sun. Without the cover the fibreglass becomes oxidised quickly especially the black around the windows. The cover is easy to put on with a zipper from the mast to the bow. I can do it...

  • Spray rail modification
    Spray rail modification
    Miscellaneous - - September 28, 2011

    Hello all or should I say ahoy shipmates, have a look at the spray rails fitted on my ship, the reason I added these was to eliminate or greatly reduce the spray that one gets in the face if one is motoring flat knacker, without the rails I would get...