On Feb. 20, 1815, the crew of the USS Constitution spotted two British ships trying to flee off the Portuguese coast. When it became clear that Old Ironsides was too fast, the HMS Cyane and HMS Levant turned to fight.

Though outnumbered, the Constitution boasted heavier ­armor and larger guns, and scored its third and final major victory in the War of 1812.

On Monday, the current crew of the storied vessel will commemorate the 202nd anniversary of the battle in the Charlestown Navy Yard. The ship will be open to the public, with tours from 10 a.m. to 4 p.m.

Admission will be free, but anyone over 18 will have to show a valid photo ID.

At noon, the time the battle started, the crew of the Constitution will give a presentation, followed by a 21-gun salute from one of the ship’s guns.

As part of the tour, crew members will tell dramatic accounts of the battle­ from the point of view of sailors who served during it.

“We like to think of our tours as interpretive history, so this will give people a chance to experience a bit of what it would have been like to be there,’’ said Mass Communication Specialist Joshua Hammond, a sailor aboard the Constitution.

Public affection for “Old Ironsides’’ has remained high. Protests have broken out twice when it seemed as though the ship might be scrapped, first in 1830 and again in 1905, leading to its designation as a museum in 1907.

The Constitution is nearing the end of a multiyear restoration and is scheduled to be put back out to sea this summer.

“Having Old Ironsides as the face of the Navy is a great source of pride,’’ Hammond said. “She’s the oldest representation of that time we still have and an incredible tool in teaching people about the Navy’s history.’’

Andrew Grant can be reached at andrew.grant@globe.com.