RedactedNarrative: On 5/9/2015 both V1 & V2 were at the loading dock trying to leave the lake. V1 was backing up past the end of the landing dock & struck V2 in the bow on the port side. When the rear starboard corner of V1 struck V2, the swim ladder attachment punctured the side of V2 and also left a scratch through the paint to the aluminum. V1 stated he hit the throttle with either his knee or hip as he sat down to drive the boat onto the trailer.  As V1 was backing up, it traveled past the end of the dock & crossed over to the other lane where V2 was sitting preparing to pull onto it's trailer.