Fairlead
A Fairlead is a fitting — a guide, roller, or shaped opening in the bulwark — through which a mooring or towing line is led so that it runs in a fair direction without chafing on the structure. It gives the line a clean lead from the shipside opening to the winch, capstan or bitts.
Types include the Panama chock (a strengthened oval opening for canal and port mooring), roller fairleads and universal multi-angle roller fairleads. A good fairlead reduces chafe and keeps the line angle within safe limits for the fitting it leads to.
Without a fair lead, a mooring line chafes on the ship structure and loads the fittings at bad angles, both of which cause lines to part. The fairlead is a small fitting that quietly protects the line and the mooring, which is why ports specify chock types and safe working loads.
What is a Panama chock?
A strengthened, closed oval fairlead in the bulwark, required for mooring in the Panama Canal and widely fitted for port mooring, giving a line a controlled lead through the shipside.