A team of seven Charles County teenagers and children dived deep to explore the unknown, and returned to the surface triumphant.

The group recently raced a submarine that they had built at the International Submarine Races at Naval Surface Warfare Center, Carderock Division, in Bethesda.

The watercraft — a single-person submarine that the group named Il Calamaro — took home the speed award for the non-propeller, one-person, independent team class.

The group also won the Spirit of the Races Award, which designated the team as the most enthusiastic. All 19 teams competing at the races voted on that honor.

Paola Adamiano-Carts and her son Sam, 16, heard about the race last year when they attended a marine forensics conference at National Harbor in Oxon Hill. A presentation about the race concluded that day. Sam, who had recently earned his scuba certification, was captivated by the idea.

“It just seemed very appealing, and we decided we would do that, and so we tried to get a group of kids his age,” Adamiano-Carts said. It was a bit of a challenge, because Sam is home-schooled.

Ultimately the team, whose members ranged in age from 8 to 16, banded together to build the craft, which is nine feet long and made of five layers of 10-ounce sheets of fiberglass.

Although the objective of the race might seem simple, Adamiano-Carts said that there was much more to it.

“You basically just go in a straight line . . . and it sounds like a piece of cake, but there were 22 subs, and we were the only independent entry,” Adamiano-Carts said. That means that their group was the only one not affiliated with a school or institution. “Some . . . never even made it halfway down the course, so it’s not as easy as it sounds.”

When the team got fully funded to begin working, Adamiano-Carts said, it found itself at a disadvantage. Because the competition is held every two years, many of the other teams had much more time to work on their crafts than the Carts Independent team, which assembled its submarine in about six months.

Despite the time crunch, the team found a lot of support in the community. Before the competition, the submarine was tested at local pools and received support from the Knights of Columbus. With that backing, the team could build its submarine and have it ready for the competition.

“We had established as a goal from the very beginning that our mission was to cross the finish line, to do things without extravagant expense and to do it with gratitude, and I feel like we met all those objectives,” Adamiano-Carts said. “We had a lot of people really chipping in. I’m not surprised we made it across the finish line, but the learning experience far exceeded anything I thought we would get out of it. The event up in Carderock . . . was so friendly and cordial.

“Everyone was willing to help, lend you tools and advice, an extra diver to get your submarine underwater,” Adamiano-Carts said.

Sam said he always has been interested in engineering. He was pleased just to have had the chance to compete and meet people from around the world with similar interests.

“It was really hard because we had to do the research and have the meetings . . . [and] everything in six months,” he said. Sam liked “meeting all the people and . . . seeing all the cool designs on the Navy base. I miss it already, but I’m excited I did it, and I definitely want to do it again if I can.”

Another team member, Katie Benoe, 17, of Chicago said she knew she wanted to join her relatives, the Gerstman family of Waldorf, when they told her about the competition in May. Katie earned her scuba certification and then traveled to Maryland two days later.

“I was part of dive support, so I’d . . . bring the sub in, take it out, establish its buoyancy, and, for a few runs, I took it out,” Katie said. “It was amazing. There’s nothing that can compare to how it felt to be a part of that team that got to participate. It was a little short notice, but it was a whirlwind experience and that made it worth it.”

Katie said her favorite part was racing the submarine. She found the experience of being in the water powerful.

“When you sit in, there’s probably two minutes . . . when you’re waiting to start, and I just got to sit and look at the water and wallow in what I was doing,” Katie said. “Being in the submarine was the best. There isn’t anything that can compare.”