Originally Posted by roverhi
If they are line control poles, there is rod/pole with a sheave at the end inside the pole. One end of the control line is secured internally at the base by a pop riveted padeye then goes around the sheave on the internal pole/rod and then to a cleat on the exterior of the pole. This is a 1-1 set up so there is no multiplication of force to move the pole in or out. It wouldn't take much in the way of restriction to lock the pole in place. Using the above methods to free it up will hopefully get it extending again.
On a 37' boat they are almost certainly line control poles and work as described above. Chances are the inside parts
are heavily corroded. If you can't free them up with water
or vinegar, you will need to drill out the rivets, take the poles apart, and inspect, clean, or replace the corroded bits as needed. Fortunately, Forespar is pretty good with replacement parts. The ends of the stinger tube (see drawing) are especially vulnerable to corrosion