A mooring device for mooring a boat at a selected nominal distance from a mooring point, with the boat being movable resiliently toward and away from the mooring point while biased into the selected nominal distance. First and second members are engaged with one another for movement relative to one another in longitudinal directions along the mooring device, and are resiliently biased, by a resilient biasing arrangement, into a nominal length which establishes the nominal distance. A band couples the first and second members for selected relative movement and enables ready adjustment of the length of the mooring device to any desired length within a range of length. A locking arrangement secures the band against movement to retain the first and second members at the selected length. Longitudinal forces exerted upon the mooring device are accommodated by the resilient biasing arrangement which militates against damage that might otherwise occur if the boat were held at a fixed distance from the mooring point or were permitted to collide with the mooring point.