RedactedNarrative: Vessel one was transiting westerly into Southwest Harbor, through the outer mooring field, during night time hours. Operator of vessel one is very familiar with the area and was piloting visually as well by aid of onboard GPS unit. While operator of vessel ones attention was focused on the GPS unit, the vessel collided with vessel 2, which was secured on a mooring within the established mooring field. Vessel 2 was securely moored with no persons onboard. A dinghy was secured aboard vessel two overhanging its stern, secured by an onboard davit system. Vessel one impacted vessel two in its stern area and was then redirected to the left or port side. Damage of both vessels was consistent with the statements of the vessel ones operator. Damage was sustained to both vessels as well as the dinghy that overhung vessel twos stern area.