A self-contained line-throwing appliance consisting of a plastic case with an end cap and 250m of line , an integral striker mechanism plus a rocket. Fired by a twist grip and used for passing a 4 mm diameter. line from ship to ship and ship to shore or for rescuing a swimmer in distress. Ships typically have to carry 4 units to comply with SOLAS regulations. Rocket propels line 250 meter in calm conditions.