Michelle Obama wrote her initials in chalk on a steel plate and a welder inscribed them in Navy tradition as the keel was laid for the future USS Illinois on Monday.
The first lady is the sponsor of the nation's 13th Virginia-class attack submarine, and the plate with her initials will be permanently affixed to the vessel.
At the keel-laying ceremony at the Rhode Island manufacturing plant for Electric Boat, the first lady called being selected as the sponsor one of the extraordinary experiences of her life.
"This is really cool!" the First Lady exclaimed, to a packed audience which included the boat's first crew.
"I am going to do my best to honor your service by being a really good sponsor, OK," the first lady told the submarine's crew. "I am going to do my job really, really well. I am going to think about you always. But more importantly, I'm going to use every fiber of my body to make sure that we live in a country that never forgets your service."
The submarine is the first naval vessel to carry the Illinois name, since a battleship commissioned shortly after the turn of the last century. That ship was renamed the Prairie State in 1941, and finally removed from service in 1956.
Rhode Island Gov. Lincoln Chafee, Connecticut Gov. Dannel P. Malloy, congressmen from both states, shipbuilders and Navy leaders took part in the ceremony. Neither Illinois Gov. Pat Quinn nor any members of the Illinois congressional delegation were in attendance.
Speakers highlighted the achievements and the dedication of the submarine industrial base.
"The vessel whose keel we lay today will be the most advanced ship in the world, its technology absolutely unmatched," Secretary of the Navy Ray Mabus said.
Mabus, who named the first lady as the ship sponsor, said Obama, who is from Illinois, will imbue the submarine with her "compassionate and indefatigable spirit."
Rear Adm. David Johnson, the Navy's program executive officer for submarines, told Obama she will share in the successes, joys, trials and tribulations of the crew and their families.
"In short, you're in for a heck of a ride," Johnson said.
The submarine doesn't have a traditional keel that runs the length of the ship because it is built in modules. A 100-foot long, 1,700-ton section of the hull for the Illinois draped with flags served as the backdrop for the ceremony.
Welder Michael R. Macomber, a 37-year veteran of Electric Boat, inscribed Obama's initials.
Construction began in March 2011, and the submarine is nearly 75 percent complete. The $2.7 billion boat is slated to be delivered to the Navy in 2016.
Cmdr. Jess Porter, the submarine's commanding officer, said after the ceremony that Obama's remarks about service members and their families resonated with him because the sacrifice of military families is often overlooked. He also said it's phenomenal that the first lady is the sponsor.