altering a rudder

[Birdseye]

contemplating extending my rudder a bit forward of the rudder stock to make it lighter on the tiller. Someone on here is bound to have done just that, so advice please. Particularly about the ratio of forward area to aft area

 

[B27]

I sailed on an Impala a few times, before and after it had the new shape rudder.
A great improvement.

 

[Tranona]

The normal range of balance area forward of the pivot is 10-15% of total area. I think I got that from an article by the designer of your boat many years ago in one of the mags. Anyway that is what I worked to in creating the balance area on my rudder and is similar to the rudder designed by the last builder of the boat. I have not calculated the actual accurately as the area was constrained by the space available and the need to create clearance for the prop. The actual construction was simple, just a shaped piece of Douglas Fir epoxied to the front face of the rudder and faired in. However this is a wooden rudder and with your GRP foam would probably be sensible for lightness, then glassed over and faired in.

Photos show the trial fit of the new area which gives an idea of the proportions and the finished job.