A water craft fender system which utilises an inflatable bladder (1) having an outer cover (10) which has edges shaped (11) to enclose a bolt rope (12). The edges (11) with the bolt rope (12) are inserted into grooves (8) of bolt rope holders 6/7 which extend around the hull of the water craft. The ends of the bolt rope (12) are secured to a bolt rope locking device which is formed of two parts (15 and 16), one of which is adapted to be attached to the hull of the water craft and the second part engages with the first part to grip the ends of the bolt rope (12).