A tragic turn of events unfolded as a woman passed away a day following a daring rescue by the U.S. Coast Guard. She, along with two family members, had been stranded on an isolated island in Massachusetts, which they reached by swimming after a fire engulfed their boat, anchored in a cove overnight on Monday.

Cynthia Sullivan, aged 73, succumbed to her injuries on Thursday. Her passing was announced in a Facebook post by a family member on Friday, as reported by Boston 25 News. The incident left her family devastated.

Tragically, the family dog, who had bravely alerted Cynthia, her 72-year-old husband Patrick, and their 37-year-old son Tyler to the blaze while they were asleep on their 30-foot powerboat, The Third Wave, also perished in the fire.

Faced with a rapidly spreading fire, the Sullivan family made the perilous swim to Naushon Island, a small landmass situated about four miles from Martha’s Vineyard.

Despite suffering burns and other injuries, the family found refuge in a barn on the island. They remained there for over 24 hours until a stroke of luck occurred on Wednesday morning when their marine radio washed ashore, allowing Tyler to reach out for emergency assistance.

The U.S. Coast Guard this week rescued a family of three who were stranded on a desolate Massachusetts island by helicopter after they were forced to swim there when their boat caught on fire, the agency said. (USCG)

“Mayday, mayday, mayday, our ship went down in Tarpaulin Cove,” Tyler is heard saying in a radio transmission to the Coast Guard. “Our ship burned while we were sleeping, and we barely escaped.”

A Coast Guard helicopter rescue crew soon arrived and airlifted the family to Cape Cod Hospital in Hyannis.

A family member had reported the Sullivans missing when they didn’t arrive home Tuesday and calls to their cellphones, which went down with the boat, went straight to voicemail.

Multiple agencies searched the area Tuesday night and early Wednesday, and were unable to get accurate pings from the family’s submerged phones until Tyler reached them on the recovered handheld radio, according to the Coast Guard.

The Coast Guard airlifted the family to Cape Cod Hospital in Hyannis. (USCG)

In a Facebook post, Chris Sullivan memorialized his mother and provided updates on his father and “hero” brother. 

“She went in peace. We played her some John Mellencamp as she passed, he was her absolute favorite, she adored him,” Sullivan wrote. “This hurts more than anything I could have ever imagined, I am leaning on my close friends and family and my two young children. We will get through this together.

“My dad is awake and breathing on his own. My brother saved both of them, he was able to get them off the boat under extremely chaotic circumstances, he doesn’t want to be called a hero, but he is. Again, thank you for all the support, it means the world.” 

The island is about four miles from Martha’s Vineyard.  (John Greim/LightRocket via Getty Images)

“Quick thinking and having quality equipment allowed the family to survive and call for help,” Scott Backholm, a search and rescue mission coordinator from Coast Guard Sector Southeastern New England, said in a statement. “Mariners are encouraged to pursue first aid training and ensure their vessels are outfitted with proper safety equipment.”

The Sullivans had left nearby Falmouth, Massachusetts, last Friday and had planned to return Tuesday afternoon.