Up to five are to be taken across Washington on the boats . Service is partially a response to the closure of all bridges from Maryland to D.C. Potomac Riverboat Company clears boats to provide service . All passengers must arrive at least an hour early for a full screening .
Up to 3,200 passengers to be taken across Potomac on seven boats . Service is partially a response to the closure of all bridges from Virginia to D.C. Potomac Riverboat Company clears security to provide service . All passengers must arrive at least an hour early for a full screening .