摘要：Concern for safety, phenomenon of a slack towline on tow-towed ships during maneuvering is important subject to be studied. This paper is aimed at clarifying a mechanism of slack towline, which comes into derivation of slack towline criteria.By applying the steady turning theory of tow and towed ships presented by Fitriadhy et al (2011)3), a simple formula was proposed for appearance limit of slack towline during turning. The formula can explain the slack towline criteria on the towing cable length, turning radius of the tug, size of the towed ship, relation with the course stability of the towed ship and so on. For the validation of the formula, it was compared with results by the tank test and nonlinear time domain maneuvering motion calculation for tow and towed ships. The theoretical tendency of the slack towline appearance limit is qualitatively agreed with the results by the tank test and nonlinear calculation. The present formula is useful for a better understanding of the mechanism of slack towline during turning.
