RedactedNarrative: V1 WAS FOLLOWING V2. V2 SLOWED ALMOST TO A STOP.  V1 OPERATOR SAID HE LOOKED AWAY FOR A MINUTE AND WHEN HE TURNED BACK, HE WAS ABOUT TO HIT V2.  V1 ATTEMPTED TO TURN LEFT BUT WAS UNABLE TO AVOID HITTING V2.  V1 STRUCK V2 IN THE REAR CAUSING DAMAGE TO THE MOTOR AND REAR.  V1 TOWED V2 BACK TO THE DOCK.