Every night for the past 30 years, Edgartown harbor master Charlie Blair has slept with a radio beside him. Now and then a voice would wake him up before the sun rose and Mr. Blair would quickly respond, heading out on the water to help a boater in distress.

Patrolling the harbor and overseeing the moorings of Edgartown have been Mr. Blair’s life’s work for the past three decades. He said he doesn’t remember ever taking a sick day, but in March he will retire for medical reasons.

“It’s bittersweet but I’ve had a wonderful time,” said Mr. Blair, who turned 76 this year.

Mr. Blair’s long history of being on the water began when he was a kid living in Coconut Grove, Fla. His father would sail people’s boats to their desired destinations and the young Mr. Blair was his best mate. He learned to tie knots, trim the sails and navigate with charts.

He also spent summers on the Vineyard, and in 1970, George Moffett, who donated the land that would become Felix Neck Wildlife Sanctuary, asked Mr. Blair if he would sail his boat from Nice to the Vineyard.

In a matter of 12 hours, a 22 year-old Mr. Blair was on a plane headed for France. It took him a couple of months to prepare the ship, but only 16 days to sail to the Vineyard.

At the wheel in 2014. — Eli Dagostino

Wanting to sail greater distances, he later joined a crew sailing to the west coast of Greenland.

“I was always under sails going somewhere,” Mr. Blair said about his youth.

By the time he was 24 years old, he was running a charter boat service out of Edgartown, directing 16 captains and moving 250 people on and off the water every day. He would work 22 hours a day, but found time to work for Steven Spielberg during the filming of Jaws in 1974.

“I slept on the set.” Mr. Blair said. “I just remember Spielberg saying ‘no one wakes the boat boy.’”

Mr. Blair explained that the film crew barely knew anything about oceans, tides, currents or horizons, and he would often be called in to advise them. By the end of that summer, Mr. Blair had made enough money to compete in the Southern Ocean racing circuit. He took first place in his class and used the prize money to buy materials to build a fishing boat. He named it Nisa, after the Greenlandic word for porpoise and a nod to his earlier ventures on the Arctic Ocean.

Nisa was launched in 1977, and Mr. Blair spent the next several years catching and selling cod, quahaugs, little necks and bay scallops.

“I still hold the bluefish boat fly rod derby record,” Mr. Blair said about the 18.75-pound fish he caught in 1984 during the Martha’s Vineyard Striped Bass and Bluefish Derby. “The only reason I still have that record is because the bluefish disappeared.”

Back in 1995. — Mark Alan Lovewell

By the time the town hired him as harbor master in 1995, Mr. Blair knew the waters around Edgartown better than anyone, having worked with ships of all sizes from dinghies to yachts. Still, Mr. Blair said the town took a chance on him.

“Previously, I tortured harbor masters and hid from them and broke every rule,” Mr. Blair said about his youth.

Times have changed since Mr. Blair first started his job. In the old days, they would write the mooring schedules on paper and the town did not accept credit cards. Mr. Blair led the department through these changes and more, and during his 30-year tenure raised millions of dollars in revenue for the town.

He would also accompany police officers to the bars at closing time to take the keys away from drunk boaters or follow them to the harbor and pull them out of their boats.

“Now there’s designated people on the boat that aren’t drinking that are operating,” Mr. Blair said. “In the old days it was like the Wild West.”

Some of the incidents he’s witnessed over the years still haunt him. He was often first on the scene after a drowning or heart attack.

Twenty-five years ago, Mr. Blair was called to the scene where a man had been mangled by a propeller during the Fourth of July festivities. There was nobody around to help him and he had no supplies. He did his best to save the man’s life before EMS arrived, but the man didn’t survive.

Dockside. — Ray Ewing

“That bothered me so bad that I couldn’t sleep for really quite a while 
. . .” he said. “It was worse than gory.”

Mr. Blair said he will carry the memory forever.

There were joyous moments too. Mr. Blair said that training young people was always the most rewarding and made all difficult times worth it. Every summer the department hires high school kids, and Mr. Blair teaches them how to run boats, manage moorings and go on rescues.

“They all say they were ‘Charlie-trained,’” he said and laughed. “These guys didn’t even know how to tie a knot.”

He estimates he has worked with an estimated 300 kids over his 30 years as harbor master, teaching some how to speak English and building up their work ethic. He noted that many police officers in town were “Charlie-trained.”

In retirement, he will miss his daily walk to the harbor, greeting the scallopers and seeing families swimming by their boats. Mr. Blair hopes whoever inherits the position will lead with kindness.

Mr. Blair’s last day will be March 27, the anniversary of his first day on the job. He said it is hard to leave, but is looking forward to some rest, spending time with his family and enjoying the water he’s been watching for so long. “The town and I had the best relationship . . .” Mr. Blair said. “There was never anything but support.”