In its heyday Tug Alley Too was towing construction barges in Boston Harbor and hauling lobster off the Maine coast. But ever since Bob and Natalie Hassold purchased the tugboat in 2001, its favorite cargo has been four to six passengers on a 90-minute tour of Portsmouth Harbor. Make a day of it by having an al fresco lunch overlooking the water at The Stockpot, which serves a tasty salmon burger and chopped chef's salad. Then head to the nearby docks for an afternoon cruise aboard the little engine that could. Captain Bob guides you away from the working harbor, under the vertical-lift Memorial Bridge, to historic Strawbery Banke, where crews of clipper ships and whalers once found good grog. Then it's onward, past the submarines being rehabbed at Portsmouth Naval Shipyard to the more serene surroundings around New Castle Island. Once you slide past Wentworth by the Sea, a grand hotel, Tug Alley Too motors out to the open Atlantic to view one of the most picturesque lighthouses along the Eastern Seaboard, the circa-1872 granite Whaleback. After your cruise, head to Izzy's for a mint patty frozen yogurt cone, the perfect ending to a perfect day.

47 Bow St., Portsmouth, N.H., 603-430-9556; tugboatalley.com. Three to five cruises daily through October. Adults $49, children under age 12 $29; $5 fuel surcharge per person.