Once alongside, the ship must be held in place. Mooring is the process of securing a vessel to a fixed structure or to the ground using ropes, wires, chains, or anchors so that it remains safely in position.

Mooring lines are run to bollards or hooks ashore; winches control tension. Breast lines, spring lines, and headlines each resist different directions of force. Tidal range, wind, and passing traffic all affect the loads on the lines. Poor mooring practice leads to broken ropes, damage, and even breakaway.

Self-tensioning winches and quick-release hooks improve safety in some terminals. Crews inspect lines for wear and replace them before they fail. A well-moored ship lies quietly alongside; a poorly moored one works restlessly against the fenders.

• Securing a ship with lines, wires, or anchors
• Uses headlines, springs, and breast lines
• Must account for tide, wind, and traffic
• Requires sound equipment and practiced crew