RedactedNarrative: Vessel 1 (V1) overturned while turning left to retrieve two swimmers being towed by an inner tube. The inner tube was tied to V1's starboard stern causing the submerged inner tube to overturn V1 while it negotiated its turn. All occupants of V1 fell overboard when the vessel overturned.
  
  All persons involved were uninjured. The inner tube being tied to the starboard stern of V1 caused V1's starboard side to be pulled over its port side and was the primary cause of the accident.