RedactedNarrative: V1 was towing v2.  V2 was tied to the port side of v1 towards the stern.  V2 was attached by 3 lines; 1 on the bow 1 one the rear starboard cleat and 1 loosely tied to the ski tower.  While v2 was being towed the nylon bow line failed, causing the line on the tower to work its way up the tower and leverage the vessel over until it capsized.  V1 was making a left had turn when the line broke