: if you meet above-normal resistance when pushing, STOP. Your
: rudder is jammed, likely a rock, and more pushing will only end up with a
: kinked cable.

Yeah, I had the cable on my commercial fibreglass kayak kinked just like
that by, of all people, a professional kayak instructor. He pushed so hard
that the tube in which the cable runs came adrift from the hand control :-(

: Put a small hole in the tip of the rudder so you can hook it
: to pull it out when it gets stuck.

Having built my skeg on the hybrid Cormorant with so little clearance that
it was easily jammed by coarse sand, one of the remedial changes I made to
that was to insert a short stainless steel loop in the bottom (I've got a
photo here somewhere - sound effects of gimping and ftping...)

You can see where the skeg was drilled (very close under the glass
surface) and the rod inserted to leave the small loop showing. This
protrudes below the keel line of the boat, but is pretty tough and small,
so it seems to be surviving any bumps on rocks, whilst being possible
to hook something into the loop and give quite a strong pull to unjam it.

However, the other remedial changes I made - to flare the edge of the skeg
box a little when repairing the damage I had done previously when unjamming
the skeg with a knife, seem to have made it much less prone to jamming,
so I haven't had to test the steel loop "in anger" :-)

Andy