A tensioning device is described for a carrying net (6), in particular between the hulls (1) of a catamaran, the carrying net (6) being fastened in a tensile-resistant manner to two mutually opposing legs of a tensioning frame. In order to attain advantageous tensioning conditions, it is proposed that one of the two legs be mounted, as the tensioning leg (5), in the tensioning frame so as to be rotatable about a pivot shaft (10) which is parallel to its longitudinal axis, the pivot shaft extending, when the carrying net (6) is tensioned, on the net side at a distance from the run-off line (13) of the carrying net (6) from the tensioning leg (5), and that an interlocking means (15) be provided for the tensioning position of the tensioning leg (5).