What is the purpose of bitts on a ship?

Bitts on a ship serve the primary purpose of securing lines, such as mooring lines or towing lines. They are strong, vertical posts typically made from steel or cast iron and are built into the ship's deck. By securing lines around these bitts, crew members can manage the tension and orientation of the lines effectively, which is essential for securing the vessel during mooring or while underway. Proper usage of bitts ensures that the ship is held in place appropriately, contributing to safety and stability.

In the context of the other options, while bitts can help facilitate mooring when lines are secured to them, the direct function of bitts themselves is not to moor the ship but rather to secure the lines that perform this action. They do not have roles in lifting cargo or navigating through water, as those tasks require specialized equipment and techniques beyond simply securing lines.