North Kingstown, R.I. — First lady Michelle Obama made her mark on the Illinois (SSN 786) on Monday at Electric Boat’s Quonset Point facility by initialing a metal plate that will be mounted on the submarine, the second vessel to be named after her home state.

She joins Laura Bush, Hillary Clinton and other first ladies who have sponsored submarines.

“I am beyond excited, and I am truly honored and I couldn’t be more proud that I have my daughters Malia and Sasha, who join me to serve as maids of honor for this vessel,” Obama said.

Her daughters could not attend the keel-laying ceremony because they had school tests, she said, but “know that you have three very solid Chicago girls who are excited to support this vessel.”

Obama signed the metal plate with chalk, then Michael R. Macomber, who has worked for EB for 37 years, welded her initials into the plate. It will be attached to the submarine at a future date.

Macomber said he spent a week and a half preparing for this moment for fear that he would get her initials wrong or that the machine would malfunction. The 377-foot Illinois is the 13th in the Virginia class and brings the Navy one closer to its goal of having 300 ships by the end of the decade.

The first lady will be affiliated with the ship for its entire lifespan, approximately 33 years. Her mission won’t end until roughly 2050, said U.S. Rep. Joe Courtney, D-2nd District, one of the guest speakers.

“How lucky they are to have a person with such an infectious, positive spirit to support and guide them through their amazing journeys,” he said.

Secretary of the Navy Ray Mabus, who role it is to name the vessel and pick the sponsor, said Obama’s actions to help military families have been immeasurable.

“Her life is one of dedication to community at every level,” he said.

Obama started the ceremony by saying: “This is really cool. I mean come on. This is so nice.”

She said she had sponsored a U.S. Coast Guard cutter before, but this was different.

“I have heard that you all are some of the most skilled shipbuilders we have around, so I am confident that this is going to be an outstanding vessel,” she said. “… You are going to be pouring your heart and soul into this vessel.”

She thanked the crew, members of the “silent service.”

“For a long time, I was one of those Americans who didn’t really know much about the service and sacrifice of military families like yours,” she said.

When folks hear about “boots on the ground,” they often think about men and women on combat patrols, or riding in Humvees or parachuting into danger.

“We often don’t hear about folks like you, deployed at sea, hundreds of feet below the waves, so we have no idea that for months at a time you don’t see the sun or breathe fresh air,” she said.

More than 1,000 people gathered for the ceremony in EB’s Bay 3, where the Illinois, the Indiana (SSN 789) and the South Dakota (SSN 790) are under construction. The facility currently is working on eight submarines.

EB President Jeffrey S. Geiger and Newport News Shipbuilding President Matt Mulherin, whose companies share responsibility for building Virginia-class submarines, each thanked officials for their support and employees for their hard work.

“There is no question that nuclear submarine construction is one of the most demanding and complex tasks that exists,” Geiger said. He said he was proud that at EB, they have the special facilities and people needed.

Macomber, the welder, has worked on more than 55 Ohio-, Los Angeles-, Seawolf- and Virginia-class submarines. He said that as a “blue-collar” worker, he was honored to weld the metal plate for the first lady.

“It’s like a feather in my cap for my career, so it’s great,” he said.

The $2.7 billion submarine is expected to be delivered to the Navy in August 2016.

j.somers@theday.com