BOSTON (AP) — The sun was starting to dip low on the horizon off Nantucket island when fishing buddies Nicholas Whitbeck and Joe Tormay spotted what they thought was a dead whale.

Squinting closer, they noticed what appeared to be a man perched on top of the “whale,” waving his hat.

The whale turned out to be a capsized fishing boat that the man — who had lost his cell phone when his boat tipped over — had been using to stay above the water as he tried to attract attention from passing vessels.

If nobody responded, the man faced a long and chilly Saturday night on water about 55 degrees F to 58 degrees F (12.8 degrees C to 14.4 degrees C) — cold enough for hypothermia to set in quickly.

Whitbeck said they'd just relocated to an area with fewer fishing vessels when they spotted the object in the distance.

“Joe initially pointed it out, thinking that there was possibly a dead whale on the horizon a couple miles from us or less," Whitbeck said. “It ended up looking a lot more like a boat that had capsized.”

Then they saw a pair of hands waving and kicked into action. The two stowed away their gear, pushed their boat to full throttle and alerted the U.S. Coast Guard.

“We got close to him, spoke to him first, got him a life jacket with a boat hook so that if in the exchange of him getting onto our boat there was a mishap or anything and he was in the water, he had a flotation device with him,” he added.

The man said he'd been sitting on the hull of the capsized boat for about an hour, drifting away from land and other boats. It was about 4 p.m. — and darkness was soon approaching.

“Us arriving at that time really was a right time, right place scenario for that type of rescue,” Whitbeck said.

The man told them that a larger wave had tipped over his boat. He said he'd attempted to flag down three other boats, but no one saw him. Whitbeck said it was just luck that they'd spotted him. They maneuvered their boat into position to get him on board.

He said the man at first was reluctant to talk about his ordeal but was “very, very grateful” when they connected later.

“It could have been an entirely different situation,” Whitbeck said. “Somebody could have come out in the morning and just found a boat capsized. Scary, but what a great ending ultimately.”

Tormay, who had Coast Guard training, said those on the water are quick to help each other out if they find themselves in trouble, especially on the island off Massachusetts.

“Any fisherman would do the same as we did," he said. “We rely on each other a lot, especially on Nantucket.”