PACIFIC GROVE, Calif. — A woman suffering from hypothermia was rescued from a California bay after spending about 15 hours in a partially submerged raft, the Coast Guard said.

The woman had gone into Monterey Bay on Tuesday evening to watch the sunset, but at some point the engine on her raft came off, opening a hole that caused it to deflate, Coast Guard Lt. Joshua Dykman said.

A fisherman found her the next morning off Pacific Grove and called the Coast Guard. Water temperatures in the bay average about 54 degrees this time of year. Air temperatures were in the low 50s.

"It's probably a very lonely, psychologically stressful situation to be out there, but she maintained the will to survive and the fact that she had a life jacket on helped ensure her survival," said Capt. Barry Perkins of the Monterey Fire Department, which also responded to the incident.

The fisherman, Mike Ricketts, and his deckhand, Joe Davi, told KPIX-TV (http://cbsloc.al/1gUH0cS) the raft was folded up and about 80 percent submerged when they discovered it about two miles offshore.

The woman was too cold to react to anything, Ricketts said. She had flares, but it was foggy in the bay, Davi said.

"From the looks of her skin, she still had some red in her and stuff, so she must have been swimming, fighting you know," Davi said.

The woman was expected to be released from the hospital in several days, KPIX reported. Her name was not immediately available.