A red nun tilts and lurches as the mighty Piscataqua rushes past the massive pilings of the Memorial Bridge. The river swirls around the Prescott Park seawall—hissing with energy—before rushing headlong into the Atlantic. With its legendary currents, 10-foot tides, and three massive bridges, Portsmouth, New Hampshire, presents its share of navigational challenges. However, with a bit of planning and some local knowledge, boaters will find this historic city to be a delightful combination of colonial charm and modern amenities.

The Whaleback Light greats boaters to the area.

Piscataqua is a big river that happens to culminate in the largest estuary in the Gulf of Maine. On a moon tide, the current can run as fast as 14 knots between the Sarah Long and Memorial Bridges. Combine this immense flow with a large commercial and recreational fleet, and things can get pretty dicey in the confines of the river mouth.

But fear not: Visiting boaters can negotiate, and even enjoy, this river. A good tip for newbies is to tune to VHF 13 and listen to the chatter of commercial skippers and the bridge tenders, the Piscataqua’s eyes and ears. The Memorial Bridge opens on the half hour, while the Sarah Long opens on the quarter hour. Break out your copy of The Coast Pilot and take 10 minutes to prep your approach. Of course, it all goes a lot more smoothly if you make the passage at slack water.

The sprawling Portsmouth Naval Shipyard on Seavey Island greets all visitors entering Portsmouth Harbor. While the abandoned hulk of the Naval Prison, with its well-armed Zodiacs and the “Use of Force Authorized” signage, can be intimidating, boaters who stick to the marked channels and keep their distance from the docks can check out the nation’s most high-tech nuclear submarine shipyard without fear of landing in the brig. There are three full-service marinas within walking distance of downtown Portsmouth. West of Seavey Island, Badgers Island Marina is a short walk or dinghy ride from Portsmouth. Hard on the Portsmouth waterfront, the Marina at Harbour Place and the city-run Prescott Park welcome transients and daytrippers who wish to explore the city. Other area marinas, including the massive Safe Harbor Wentworth Marina on New Castle Island, can also accommodate visiting boaters and get them into town.

Portsmouth is colonial at heart. Just a block from Prescott Park, Strawbery Banke Museum depicts life in Portsmouth since its days as a 1630’s English settlement, through its heyday as a major fishing and shipping port in the 18th and 19th centuries, to its industrialization in the 20th century. As you stroll the museum’s narrow lanes and cobblestone streets, be prepared to meet and chat with coopers, masons, merchants, captain’s wives, and sailors.

The USS Albacore Center gives visitors a chance to tour the pre-nuclear-era submarine.

Just across a small bridge at the southern end of Prescott Park, the commercial fishing fleet ties up at Pierce Island. Draggers and lobster boats bearing names like Atlantic Offspring, Intrepid and Storm Dancer lie snug against the dock, awaiting their next trip and giving Portsmouth the air of a real working port, which of course it still is.

In a boat, passing below this bridge takes you back in time to one of the city’s oldest neighborhoods. You can tie up at Geno’s Chowder & Sandwich Shop or the River House for a quick bite and stroll down Mechanic, Gate and Washington Streets, where clapboard and shingled homes crouch alongside the brick sidewalks, their rooflines crooked, their walls visibly warped, yet centuries strong.

Yet the modern world is never far away, making Portsmouth a city of contrasts. Over the colonial skyline, the cranes and massive steel girders of the Naval Shipyard loom. The Piscataqua—the Gundalow Company’s replica of the vessels once used as river workhorses—is dwarfed by massive tankers moving upriver to offload heating oil, food, and other commodities. The Ceres Street cobblestones that once chattered under the wheels of horse-drawn carts now rattle beneath the soles of well-heeled tourists.

It wasn’t always that way, of course, for Portsmouth endured decades of hard times following the collapse of the coastal mills. The city took advantage of federal funding to restore its old port in the 1980’s and 1990’s, creating a haven for shopping, dining, and entertainment within the confines of several walkable blocks.

Look to the sky, find the towering white steeple of North Church, and follow it to Market Square— Portsmouth’s hub—where boutiques, spas, bakeries, coffee shops, restaurants, and pubs await. Along Market, Bow, Daniel, and Congress Streets, shoppers inspect everything from designer duds for a night on the town to shorts and sandals for bumming around.

The Discover Portsmouth Center on Middle Street is a great place to learn more about the city’s cultural events, while the Portsmouth Music Hall welcomes big-name acts. Performances range from opera to reggae, from art house cinema to readings by renowned authors. Meanwhile, the Seacoast Repertory Theater serves up musical favorites and modern British and American dramas.

Bursting with energy as if drawn from the river’s swift currents, Portsmouth is a city building a bright future with a sharp eye on its past.