Sounds like a rudder on a Mac 26 I had. A "sheet" (rope) attached to front of rudder (or side) feed up to Tiller handle area (for the Mac, it was a rope attached to steel cable attached to rope where it fed to rudder).
From there, I tied it off on a small T cleat attached to tiller handle. Some folks used a Clam Cleat so they could release quicker when getting in too shallow of water.
I have to make a make a tiller/rudder for a small Bandit I just got. Plan to semi copy same system. Handy for beaching boat and not breaking rudder.
-Bookmon