79-year-old dead, 3 missing after boat carrying family sinks in SF Bay during memorial service

SAN FRANCISCO -- One person died, three people were missing and 16 were rescued from the waters off San Francisco after a boat sank Tuesday afternoon while carrying mostly family members as part of a memorial service, authorities said.

Crews arriving on the scene near Alcatraz Island found a three-deck vessel almost fully underwater with the motor still running and leaking fuel, San Francisco Fire Chief Dean Crispen said.

Clifford Joseph Boisa, 79, of Sutter County, has been identified as the one person who was taken from the water but later died.

• Total aboard: 20 adults

• Rescued: 16 individuals confirmed

• Deceased: 1 person

• Missing: 3 people

• Animal casualties: One dog aboard the vessel also died.

The vessel's motor was still running and leaking fuel when rescuers arrived, Crispen said.

"Our understanding was there was some kind of memorial service that they were engaging in," Crispen said at a news conference. "They were hit by a wave or took on water, and the boat capsized."

Three people who were sent to the hospital have been released as of Wednesday morning, officials confirm.

Search operation continues

The U.S. Coast Guard says it is still conducting searches for the three missing people as a rescue rather than a recovery mission.

Officials have shared more about the technology rescue crews are using in the search. The teams are using thermal imaging, tide prediction and modeling technologies to help guide them.

As the search continues for the missing people, salvage crews are working to recover the boat, which has been difficult.

Search crews are typically trained to be able to pull things from water up to 60 feet deep, which covers most of the Bay Area. However, the boat sank in the shipping channel, which is much deeper at about 120 feet.

By Tuesday evening, authorities had been searching in the open ocean on the western side of the Golden Gate Bridge. The efforts have involved divers, helicopters and vessels.

In July, the average temperature of the bay at 7 a.m. is around 59 degrees, according to the Pacific Open Water Swim Company. That's cold but not life-threatening.

All the people rescued Tuesday were taken to the Gashouse Cove Marina in San Francisco.

What caused the boat to sink?

Officials say they're still piecing together exactly what caused the boat to skink. It was a three-story, 49-foot private yatch out of Stockton, California.

Crispen said the vessel was believed to have launched near the St. Francis Yacht Club in San Francisco. A person who answered the phone there said the club did not have any information on what happened.

The San Francisco Fire Department says that when reports first came in of the boat capsizing, there was steam visible from the boat, which was misinterpreted as smoke.

Officials later confirmed that there was no fire on board.

Longtime San Francisco Bay sailor Mike Peterson says incidents like these are rare.

"It would take something happening very rapidly to cause a boat like that to go down and people like that to end up in the water," said Peterson. "You have the wind coming one way and the tide coming another. It makes it very choppy and rough. Especially in the afternoons. That's exactly what happened here," said Peterson.

The Associated Press contributed to this report.

Stay with ABC7 News for the latest details on this developing story.