You need a mast crane.
You dock the boat alongside the crane.
Set up saw horses on the shore side of the crane to hold the mast.
Fasten wood fixtures to the boat fore and aft to support the mast in shipment.
Loop a line around the mast under the spreaders and take out most, but not all of the slack.
Loosen, disconnect, and gather the stays with light line.
With one person at the foot of the mast, and one on the crane, take the slack out of the line, and lift the mast about 6 inches over the aluminum step fixture inside the bottom of the mast.
Label and disconnect the electric cables running inside the mast.
Tie the stays to the bottom of the mast.
While one person tends the foot of the mast, lift it a few feet above the base of the crane, swing it ashore,
Lay the mast on the sawhorses.
Securely tie the stays to the mast And prepare it for shipment.
Lift the mast with the crane, and set it on the wood fixtures.
Fasten the mast down securely with multiple straps to the toe rails.
The boat is now ready to take to a lift for transfer to a trailer.
The crew at our marina would do this for a fee, using the crane on one of their lifts.
The 75-83 h27 is not designed to be easily trailerable, but I have seen them hauled out on trailers for transport to the owner’s place for the winter, or transport by an owner. We took our mast down this way every winter for three seasons until we moved to a marina that can lift and position our boat for storage with the mast up.
Later 24 to 26 foot Hunters, Catalina, and Macgregors have masts with hinges (tabernacles), and water ballast to reduce towing weight. They are well designed to meet your needs. At 7,000 pounds, the ‘80 h27 is a load to tow, requires the steps above to trailer, and rides higher because of its lead keel.
Good luck!