Unit 2 was heading east at half throttle when he spotted Unit 1 closing at a high rate of speed. Operator of Unit 2 saw a collision and jumped off. Unit 1 seemed to be unable to reduce speed losing control and striking Unit 2 on the starboard side. Operator of Unit 1 was knocked unconcious. All were transported to Bushy Park where EMS transported to MUSC for tests. Operator 1 was interviewed but had no memory of the accident.