RedactedNarrative: Unit 1 was traveling approximately 45-50 mph according to operator.  Unit 2 was traveling approximately 15 mph according to operator.  Unit 1 was overtaking Unit 2 on Unit 2's port within too close of a distance.  Unit 2 made a turn to his port side and Unit 2 and Unit 1 collided.  Impact was on port front of Unit 2.  Impact was on starboard rear of Unit 1.