On the morning of July 4, 2026, a three-masted wooden frigate eased away from her pier at the Charlestown Navy Yard in Boston. Her crew wore uniforms modeled on those of the War of 1812. Tugboats stood by, crowds lined the Harborwalk, and off Castle Island her guns fired a 21-gun salute to mark 250 years since the Declaration of Independence.

The ship was USS Constitution, nicknamed “Old Ironsides.” She was launched in Boston on October 21, 1797, and she is still a fully commissioned US Navy warship, with an active-duty commanding officer and crew. The Navy describes her as the world’s oldest commissioned warship afloat.

A ship with a serious résumé

Constitution was one of the first six frigates built for the young US Navy. She served from 1797 to 1855, fighting in the Barbary Wars against North African states and, most famously, in the War of 1812 against Britain.

Her nickname comes from an 1812 battle with the British frigate HMS Guerriere. During the fight, British cannonballs were seen bouncing off her thick oak sides, and a sailor reportedly shouted that her sides were made of iron. She won the battle, and the name stuck.

She came close to being scrapped more than once. In 1830, a poem called “Old Ironsides” by Oliver Wendell Holmes helped stir up public support to save her. Since then she has been repeatedly repaired and restored, most recently in a major dry dock overhaul between 2015 and 2017.

Why the Navy turns her around

Constitution heads out into Boston Harbor several times a year. The 2026 schedule included underways for the Battle of Bunker Hill anniversary, Independence Day and Sail Boston, with another planned for October 21, her birthday. Most of these trips end the same way: she comes back to the pier facing the opposite direction.

That isn’t just for show. A ship tied up in one position for months on end has one side constantly facing the sun and the prevailing weather, while the other side is relatively sheltered. For a wooden hull, that matters. The exposed side dries out, heats up and takes more abuse from rain, wind and UV light, while the other side stays cooler and damper.

So the Navy swaps them. As the USS Constitution Museum puts it, a wooden ship needs to change position at least once a year to weather evenly on both sides. In the 19th century this was known as “winding” a ship. Today, the trips are called turnaround cruises.

What uneven weathering does to wood

Wood is a natural material that reacts to its surroundings. It absorbs moisture and swells, then dries and shrinks. When one side of a structure goes through much bigger swings of heat and moisture than the other, it can wear unevenly. Paint and finishes break down faster, seams and caulking can loosen, and small cracks can open up where water later gets in.

On a ship, those problems add up. Planks that shrink and swell at different rates can put stress on fastenings and joints, and damaged areas become entry points for rot. Rotating the ship spreads that wear more evenly across the hull. Combined with regular inspection and repair, it helps make expensive major restorations less frequent.

It’s the same principle behind rotating your car’s tires, or turning a mattress. When something wears from one direction, you change the direction.

Sailing, or being towed?

One honest note about those trips: on most turnaround cruises, Constitution doesn’t move under her own sails. She’s usually guided out into the harbor and back by tugboats, with her sails furled. For a 228-year-old ship carrying hundreds of guests through a busy port, that’s the safe way to do it.

She has sailed under her own power on rare occasions. In 1997, for her 200th birthday, she set her sails and sailed unassisted for the first time in more than a century. She did it again in 2012, to mark 200 years since her victory over HMS Guerriere. Those voyages were carefully planned events rather than routine outings.

How much of the original ship is left?

After more than two centuries of repairs, a natural question is how much of Constitution is actually from 1797. The honest answer is: not a lot. Much of her timber has been replaced over the years, plank by plank and beam by beam, as old wood wore out.

Historians and preservationists still regard her as the original ship, because she has been continuously maintained rather than rebuilt from scratch, keeping her original design, structure and identity. It’s a real-world version of an old puzzle known as the Ship of Theseus: if you replace every part of something over time, is it still the same thing?

For the Navy and the people of Boston, the answer is clearly yes. Every new plank goes into the same ship, built to the same plans, doing the same job.

Still on duty

Today, Constitution’s job is mostly ceremonial and educational. Her crew gives tours to visitors at the Charlestown Navy Yard, takes part in public events, and represents the Navy at home and abroad. The ship is open to the public for free most days of the week.

But every time she’s eased away from her pier, saluted with cannon fire and brought back facing the other way, she’s also getting a bit of practical maintenance. It’s a 19th-century solution to a 19th-century problem, and it still works.