Original rudder design.
I have my father's original drawings for the 1972 ('Mk 1') version of the Hunter 25.This is a modified spade rudder (mounted on a piece of keel, not an indepedent skeg) with what appears to be the correct 18% of the area forward of the rudder stock. If Hunter or a 'PO' altered it on a later or used boat, I wouldn't know anything about it.I would be very judicious before assuming it's the rudder by checking out other things first. Old or misshapen sails, ineffective sail trim, poor headstay tension, incorrect mast rake, and unbalanced vessel trim or crew weight could all be factors in why a boat of this size behaves sluggishly. All of these things can be affected positively or negatively by the user. In other words, YOU may be able improve the situation.(I will share with you that MOST people I have heard from regarding a boat's unwillingness to perform well have expressed surprise at suggestions about rigging tension, sail trim, and mast rake-- they simply had not expected that things like this could be at fault.)If you must compare the design drawings to what your boat looks like I can provide copies. EMail me.J Cherubini IICherubini Art & Nautical Design Org.jcomet@aol.com