 A 4th of July spent boating on the Potomac River almost ended tragically. Would have if it weren't for the heroic efforts of first responders in Prince George's County, Fairfax County, and D.C. WTOP Cheyenne Curran was at the National Harbor and on board one of the Prince George's County police boats involved in the rescue. Around 11 p.m. last night, a boat on the Potomac River with seven people on board hit an unlit buoy. The vessel had crashed and was taking on water.