All wave energy must pass

The weather is approaching, and you are checking the lines on your boat.

- PHINEAS SPRAGUE

Set up dock lines to allow wave energy to pass by the boat, rather than strapping the boat down tight.

The owner of the boat near you is attaching his boat to the dock with a spider web of lines. The lines are effectively absorbing huge pitching and rolling forces. Stressing the docking lines unnecessarily is counterproductive to the mission of keeping the boat safely alongside the dock. Wherever a stressed line crosses a chock, heat builds up and strands part. Your sinking realization is that the real problem presented by the upcoming weather is that this neighboring boat is likely to visit your boat for an impromptu and expensive dance.

Independent dock lines

Docking lines work independently to pass rolling and pitching stresses back and forth between them, positioning the boat alongside a dock so that it can breathe and let the waves pass under it without removing energy. The exercise is about minimizing unnecessary forces on the lines and tuning necessary holding forces to work together. When the boat can’t pitch freely, the chocks concentrate the forces of lifting the dock and become dull knives.

In most situations, one only needs four well-placed dock lines (two spring lines, a bowline and a stern line) and three robust fenders to achieve a configuration that positions the boat alongside.