RedactedNarrative: (V2) was attempting to moor his vessel to the starboard side of(V1), which was at anchor. Two other vessels were moored to the port side of V1: Vessel 3 and vessel 4.  Two unknown vessels (V5 and V6) were passing to the starboard sides of vessels 1,2,3, and 4 and going upstream. A large wake pushed the rear of the port side of V2 into the starboard pontoon of V1, striking the pontoon twice. Three vessels were in motion, V2 and the two unidentified vessels, V5 and V6. I have interviewed the operators of vessels1,2,3, and 4 and can reach no conclusion as to who created the wake. Of the two vessels actually involved in the collision, vessel 2 was the only vessel in motion, as it had not yet been moored to V1 and was trying to take evasive measures.