RedactedNarrative: V1 was cruising north bound along ICW.  V1 made a sudden turn to its starboard side and made contact with V2 that was cruising parallel to V1.
  
  V1 makes a sudden turn to its right (starboard) side and into the path of V2. (V1) stated that he checked the side mirrors then made the turn. (V2) seeing the course change of V1, increases speed and turns to the right (starboard).  V1 makes contact with the left (port) rear side of V2.  OP1 is thrown from V1, but is uninjured and is able to get back on his vessel. Both vessels go into the Siesta Key Watersports docking area just east of the incident location.