What is a 'spring line' used for when docking?

The concept of a 'spring line' is essential for effective docking techniques. A spring line is used primarily to control the lateral movement of a boat while it is being docked or undocked. When used correctly, it helps to pivot or turn the boat against the force of the wind or current, facilitating a smoother and safer approach to the dock.

Deploying a spring line allows a vessel to leverage its engine power while maintaining control of direction. When one end of the line is secured to the dock and the other is attached to the boat, it helps pull the vessel towards the dock in a controlled manner, creating the necessary angle to counteract any external forces affecting the boat’s position.

The other options pertain to different functions related to docking or boating but do not describe the specific purpose of a spring line. For instance, securing the boat in place would typically involve using bow and stern lines, while raising an anchor is unrelated to the use of spring lines, and measuring distance to the dock involves techniques that do not include spring lines. Understanding the role of a spring line is crucial for boat handling, especially in challenging docking situations.