It survived battles with pirates and shellings by the British navy. But these days, America's oldest warship is fighting an inescapable foe - rain.
As Americans celebrate their Independence Day, about 600 people will board the 209-year-old USS Constitution for its annual July 4 voyage - a two-hour trip in Boston Harbour to turn the ship around.
A team of 27 civilian carpenters, mechanics and historians each year go through several hundred pounds of wood and some 200 gallons (909.2 liters) of paint, trying to erase the marks of time and weather on the ship affectionately known as "Old Ironsides."
"Saltwater preserves wood," said Robert Murphy, one of the ship's chief caretakers. "Freshwater is our enemy."
That enemy's assault on the Constitution, which is still listed as an active Navy warship, has been unrelenting this year. Boston just ended its wettest June since 1872 and so far this year has received 32.2 inches (81.79 cm) of rain, according to the National Weather Service.
Rainwater that seeps into the wooden ship's frame can induce rot in its timbers. Only 15 percent of the ship's original wood remains and most of that is in the keel, below the waterline, Murphy estimates.
On a recent tour of the ship, puddles of water on the deck had Murphy contemplating his next big project - replacing the entire deck to restore the gentle slope that wooden ships use to ensure that water rolls off.
Murphy, 56, spent 34 years repairing modern US Navy ships before overseeing maintenance of the Constitution's four decks, three main masts and 10 miles (16 km) of rigging ropes.
"What I did when I started here was step back 200 years, in terms of technology," said Murphy, who has worked on the ship for four years and whose father and grandfather also worked in Boston shipyards. "It was an adventure at first."