His four-year Vineyard run has been marked by a historic fire, an award-winning crew and a record number of law enforcement boardings. He has lived at the West Chop lighthouse station with his wife Andrea and two children, Emma, five, and Gabe, three, who was born here.

But now it’s time for a change of command for senior chief Jason Olsen at the U.S. Coast Guard Station Menemsha. On Friday, he will be relieved by senior chief Robert Riemer in a ceremony at Menemsha. Mr. Olsen has been reassigned to South Portland, Me., to a buoy tender station where he will be executive petty officer in charge, the second in command. He begins his new duties July 2.

Mr. Olsen, 39, has served in the Coast Guard for nearly 18 years. He has high standards and a wide smile. And looking back at his time on the Vineyard, he said it has been the most challenging chapter in his career.

“Not only because of the boathouse fire but also being in charge in an isolated area with so many different personalities with a younger crew,” he said in a recent interview from his office overlooking Menemsha harbor. “It’s been a great learning experience. I’m going to tell this crew when I leave that I’ve learned more in my four years here than in my entire Coast Guard career.”

The senior chief is trading his Menemsha command post for a 175-foot boat with a 25-person crew. He’ll spend 10 days a month on the water. Sometimes he won’t be far from the Island — the station’s area of responsibility reaches to Cape Cod Bay.

He looks forward to the shift in duties. “It’s a total change of scenery and a career changer,” he said. “I’ve done small boat stations for eight years now. It will be nice to do something different. It’s going to be great.”

Still, he has mixed feelings about leaving the Vineyard. “I met a lot of awesome people, the family has had a great time here, the schools are awesome, winters can be challenging and dealing with the ferry schedules, but if you get used to that, it’s a great place,” Mr. Olsen said.

He had never planned to join the Coast Guard. Growing up in San Diego, Calif., he babysat four kids for a submariner in the Navy and had an interest in joining the Navy reserves. Then he saw an advertisement in a local Penny Saver for the Coast Guard.

“I’m like, the Coast Guard, what is that?” Mr. Olsen said. “[The submariner] said I should definitely do it. I called and pushed and pushed and I actually got to go to boot camp early because I kept pushing. I joined when I was 21.”

Once he started doing search and rescues, he knew he had found his career calling.

“I wanted to save people,” he said.

There’s a sense of pride in being a part of the military and Coast Guard, Mr. Olsen said.

“Especially when people don’t know you or your kids, Emma will go around say, hey chief,” he smiled.

Mr. Olsen has served in Fort Pierce, Fla., Bayonne, N.J., Sandy Hook, N.J. (where on a port call he met his wife at Grumpy’s Pub in Woods Hole), Fort Macon, N.C. and the Vineyard. He has a 15-year old son Josh, who lives in Maryland with his mother, also a Coastie.

The day July 12, 2010 will always remain fresh in his mind — that was the day a fire broke out in the Coast Guard boathouse in Menemsha, engulfing the surrounding piers in flames and destroying the 68-year-old red-roofed building that was a waterfront icon.

Chief Olsen had been on the job for six weeks.

“I don’t like what-if-ing, but every once in a while I do say, if this boathouse fire didn’t happen, how would this tour have been different?” he said. “I don’t want the boathouse fire to be the pinnacle of my four years here. Unfortunately, it was a very high-profile incident. I’m still very thankful that nobody got hurt. I’m still amazed that six different towns came together and put that fire down and kept it from spreading.”

During the fire and the investigation that followed, Mr. Olsen’s duties expanded; not only was he charged with leading his crew, he also was thrust into working closely with local officials.

“It exposed me to Island politics, which is very unique here,” he said. “As an officer in charge and leading the crew, you have to focus on the crew but also the external entities. I think it was a challenging but rewarding experience. The closeness I’ve had with the community, it’s been phenomenal.”

A new boathouse is under construction and expected to be complete sometime next year. Mr. Olsen will return for the ribbon cutting.

“I want that closure, I want to see that ribbon cut,” he said,

He said a favorite memory he will carry with him is from Christmas on the Vineyard.

“Every Christmas the town comes over and drops off all this food — I’ve never seen anything like it,” he said. “Most places you’re not going to get that. I’m truly going to miss it.”

This year the station received the prestigious Sumner I. Kimball Readiness Award, one of the highest wards in the service. Mr. Olsen kept it a surprise until the day of the award ceremony in November. The isolation of the Vineyard poses challenges, Mr. Olsen said, but he and the crew learned how to make it work.

“There are challenges of trying to keep the crew motivated personally and professionally,” he said. “But they’ve been a great crew.”

Mr. Olsen is eligible for retirement in two and a half years, but he doubts he will take it.

“I don’t want to get out,” he said. “I’m having too much fun.”

The change of command ceremony takes place at 10 a.m. Friday in Menemsha.