In this paper the results are presented of a model study into the behavior of anchor lines as used in the offshore mooring of a wide variety of floating structures. For this study model tests have been carried out with a buoy moored to four chains. The effect of model scale, pre-tension in the lines, wave height and wave period on the line tensions is discussed. Special attention is given to the dynamic behavior of the mooring system, resulting into higher tensions than would follow from calculations based upon the static catenary theory. The existence and significance of dynamic effects is confirmed by the results of forced oscillation tests with model anchor chains in calm water.