RedactedNarrative: V1 was docked north of four rental pontoon boats and began to exit the docking area.  O1 lost control of V1 as it backed past V2, V3, and V4.  V1's throttle was stiff and excess force by O1 caused the engines to rev in gear, causing V1 to move rearward at a faster than necessary speed.  The stiffness of the throttle made it difficult to correct the action.  V1's starboard stern struck V2 as it tried to back in an arc in preparation to leave the dock area.  V1 then struck V3 and V4 with its starboard gunwale as it swung rearwards to the west.  V1 then struck the opposite inside corner of the T dock with its starboard stern, breaking a hole in the corner of the stern.  V1 then left the dock area and motored west to a less crowded dock.