New Hampshire Marinas. While it may be known most famously for its Prescott Park Municipal Dock. Portsmouth, NH. (7). $15 - $ - Dock. $3 - $92 - Day. 10 Prescott Park Boat slips are available for Seasonal Rental in the lottery. City of Portsmouth Prescott Park Offical Website, Docks. Your Credit Card will be charged at the Resident Rate if a dock slip is available. Boat Length.