WINDHAM — From the time he was growing up on Casco Bay, Michael Davidson knew his career would be on the water.

Raised in South Portland, he spent summers on Great Diamond Island, where the ocean is part of the neighborhood. As a teenager, he signed on as a deckhand with Casco Bay Lines, and took to the work like he was born for it, becoming a captain before he enrolled in Maine Maritime Academy.

“It points to Mike’s experience level and commitment to being a professional mariner,” said Nicholas Mavodones Jr., operations manager at Casco Bay Lines, who has known Davidson since they were children and worked alongside him when they were young men. “He has always taken the job very seriously.”

Davidson’s family kept a grim vigil Monday, waiting for news from the Coast Guard, which was searching an expanse of the Atlantic Ocean the size of California for survivors of one of the worst maritime disasters in decades. While Davidson’s wife, Theresa, was in Jacksonville, Florida, with relatives of El Faro crew members, other family and friends gathered at the Davidson home on Fox Court in Windham, where about a dozen cars were parked in the driveway.

Meanwhile, a wide circle of mariners with whom Davidson, 53, has served also waited hopefully, even though that hope dwindles with each passing day.

“We’re watching this very closely,” said Doug Lamson, a South Berwick native who is fleet operations manager for ConocoPhillips, where Davidson once worked. “Myself and many of our mariners here know Mike very well and find this very upsetting.”

Davidson worked for Casco Bay Lines as a deckhand in the 1970s and 1980s, for some of that time under the command of Larry Legere.

“He was a very energetic, enthusiastic worker. He did his job well, moved up the ranks and got his captain’s license very quickly,” said Legere, now an operations agent with Casco Bay Lines.

After graduating from South Portland High School, Davidson enrolled at Maine Maritime, graduating in 1988. He worked for Arco and ConocoPhillips, before going to work for TOTE Maritime.

Legere said he spoke with Davidson a few weeks ago, when Davidson was headed out to Peaks Island to visit his mother-in-law. He was in great shape, as usual, Legere said.

“He looks a lot younger than his age, which is a pretty tough thing to do when you’re a mariner,” Legere said.

Pat Wetmore, a neighbor on the Davidson’s quiet cul-de-sac for the past 20 years, said Davidson was exceptionally nice, offering help if she had anything heavy that needed moving. When a large branch fell off an oak tree in her front yard, Davidson cut it up for her.

When Davidson wasn’t at sea, he was home with his family, two college-age daughters, Ariana and Marina, and his wife.

“He’s very devoted to his family and his children especially,” said Mary Emmons, a neighbor. “He wasn’t home much. When he was, he would do family stuff.”

Davidson was fond of her 8-year-old grandson, Eric, who adored Davidson.

“They’re good people,” said Roberta Emmons, Eric’s mother. “I just want them found.”

Sean Grossman, a student at the University of Southern Maine, said that when he moved into the neighborhood last summer, he asked Davidson who his Internet provider was. Until Grossman got service, Davidson gave him the password for his Wi-Fi network – the signal could reach Grossman’s house.

The life of a ship’s captain is one of constant attentiveness, say fellow mariners, and it is not a profession one chooses without an aptitude for precision and preparation.

“It’s not an environment where you can’t take it seriously all the time,” Mavodones said. “Whether it’s the weather, the sea and wind, the cargo you have on board, the passengers on board or your crew – everybody in the business takes it very seriously.”

In one of her only public comments since the ship was reported missing, Theresa Davidson told the Daily Mail of London on Friday, “My husband is extremely capable, he has extensive training. … If anyone can handle a situation like that, it’s my husband.”

Legere said that as a seasoned mariner, Davidson would have approached his situation with concern, not fear. But when the engines stopped, the situation would have been dire.

“In the one big storm I was in down off the coast of Mexico with 12- to 20-foot seas, the waves were coming up over the catwalk, 10 feet above the main deck, and the ship listed to 23 degrees,” he said. The tanker’s engines didn’t stop, as they apparently did on the El Faro.

“Anybody who has gone on the deep sea, that is the main thing. Once you lose propulsion, you can’t maneuver, and if you can’t maneuver, you can’t get out of the way of bad weather,” Legere said.

As the Coast Guard continued to retrieve debris and concluded that the El Faro had sunk, concern turned to sorrow among Davidson’s friends and colleagues.

“Our thoughts and prayers go out to the families and crew,” Lamson said. “Hopefully there is a miracle, but as the days go on, it’s less and less likely.”