Folbot Sailing Rudder Mounted On A Feathercraft K-1
The K-1 surf rudder (above left) is too small for sailing.  Chesapeake Light Craft has been using the K-2 rudder (above center) with its single sailing kayaks.  I found the K2 rudder still too small and modified a Folbot rudder (above right) to fit the K-1.  
The Folbot rudder pin (above left) is unmodified.  The right pin above has been modified, the shaft is 1/4" longer fit the K-1. 
Unmodified Folbot rudder mounted on a Folbot Aleut.
Continue to rudder pedals
Modified Folbot  rudder mounted on a Feathercraft K-1.
The rudder blade can be lifted up out of the water so that it extends straight back.  On my K-1 it cannot and should not be flipped on the back of the deck.  It would interfere with the sail sheet which is attached to the aft grab loop.

For a good discussion on balanced rudders and the necessity to add a tensioning line to the rudder please see pp. 143-144 of the
Complete Folding Kayaker by Ralph Diaz.
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