Which mooring hardware is typically used to secure lines aboard a vessel?

The correct choice is cleat, which is a common piece of mooring hardware utilized on vessels for securing lines. Cleats are designed to provide a solid and accessible point where crew members can tie off mooring lines securely. The design of a cleat features two upward-facing horns that allow lines to be wrapped around and secured, which ensures that the lines do not slip under tension. This feature is critical for maintaining control over the vessel when it is docked or moored.

While winches, poles, and capstans are related to line management, they serve different functions. Winches are primarily used to haul in or let out lines through mechanical means, but they do not serve as a securing point. Poles may refer to various structures on board, but they do not function as hardware for securing lines. Capstans, similar to winches, are used for winding line but are also not the primary method for tying off mooring lines on a vessel.

Cleats are vital in ensuring that mooring lines are properly secured, enabling safe and stable mooring of the vessel, making them the most appropriate choice in this context.