I seem to recall that you have a Tayana 42. Some of these boats had turning blocks on the deck to lead halyards to deck winches or back to the cockpit. Now this is occurring minutely, so it's not a direct safety issue. My thought was to install a plate or something similar on the cabinhouse just forward of the mast exit, and to throughbolt that to an eye, then to run a wire with a turnbuckle to the keel. There are some nice bolts on the mast step taht I could use to attach the bottom.
Earlier suggestions are right on.
I seem to recall that you have a Tayana 42. Some of these boats had turning blocks on the deck to lead halyards to deck winches or back to the cockpit.