Next time you rig it up. Take some pictures of your boat and its rigging. The bar at the bottom of the mast is for the rotation control. It may have positive control if connected to the cleats on the main beam. If you have a grommet in the tramp just behind that point the lines may run to the sides allowing adjustment by crew without having to go to the mast. OTOH, it may attach to the bottom of the boom. Same purpose, reduce/control the amount of mast rotation.

Pics would help a lot.

Clayon