RedactedNarrative: Boat #1 was cruising east along north side of island toward east-most point.  boat #1 with 6 passengers and 3 riders on one 3-person inner tube was traveling around 20-25 mph.  Toward the end of the island boat #2 was traveling from port direction of boat #1 and crossed over toward the tubing area, colliding with tuber while she was on the tube.