Alcatraz boat victim identified as 79-year-old; Coast Guard ends search for 3 missing

A former California reserve deputy sheriff has been identified as the person who died after a pleasure boat carrying members of an extended family capsized in the frigid waters of San Francisco Bay near Alcatraz Island.

Clifford Joseph Boisa, 79, of Sutter County, died after the three-level recreational vessel sank Tuesday afternoon with 20 people aboard, authorities said. The Sutter County Sheriff's Office confirmed to Fox News Digital that Boisa served as a reserve deputy sheriff beginning in 1987.

Three passengers remained missing Wednesday after 16 others were rescued, including three people who were taken to local hospitals. 

The U.S. Coast Guard said Wednesday it planned to suspend its search for the three missing passengers at sunset after crews spent roughly 23 hours searching more than 950 nautical square miles of San Francisco Bay.

"We have completely saturated the search area," Coast Guard Sector San Francisco Commander Capt. Jarod Tosczko said during a Wednesday news conference, thanking Good Samaritans who helped rescue people from the water.

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Tosczko said it is possible the three missing passengers are trapped inside the 49-foot vessel, which rests about 130 feet below the surface. Investigators plan to use an underwater drone to find the boat before determining whether to recover the victims and raise the vessel.

The passengers were members of an extended family gathered for a memorial service that included scattering a loved one's ashes in San Francisco Bay, according to a report from The New York Times.

The pilot of the boat was among those hospitalized and has since been released, officials said. 

Authorities said everyone aboard was either related or a close family friend, and no children were on the vessel. The names of the three missing passengers have not been released.

San Francisco Fire Chief Dean Crispin said crews were dispatched at about 3:35 p.m. local time after receiving reports of a vessel fire roughly 600 yards off Alcatraz Island between the former prison and the Golden Gate Bridge.

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When first responders arrived, they found no evidence of a fire, but instead discovered the boat had capsized while returning from Angel Island and was already mostly submerged.

Crispin said the San Francisco Police Department's marine unit found the vessel with only its upper deck above the water. The boat's engine was still running, and fuel was leaking into the bay.

One person was found in the water, while the remaining occupants were located inside the vessel's top compartment before rescuers pulled them to safety, he said.

Authorities have not yet determined what caused the boat to sink. Investigators are examining factors including the vessel's stability, weather and water conditions. 

Officials said the boat appears to have taken on a wave, become swamped with water, rolled over and sank, though the investigation remains ongoing. 

Strong summer winds and rapidly changing conditions on San Francisco Bay are known to create dangerous boating conditions.

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Commercial fishermen Mike Montoya and Justin Marceline, who rushed to help after the vessel went down, described a frantic rescue as passengers fought to escape.

"There was even people banging at the windows as they were like filing out, and as soon as people were hitting the water, we were just trying to pick them up as fast as we can," the fishermen told NBC Bay Area. "Some people didn't even have life vests on and they were drowning."

Before announcing plans to suspend the search, Coast Guard and San Francisco Fire Department crews searched using boats, helicopters, thermal imaging, tide predictions and drift modeling to search for the three missing passengers.

The Sutter County Sheriff's Office told Fox News Digital it had no additional information to provide about Boisa. Fox News Digital also reached out to the San Francisco Fire Department for additional information.

Officials said the vessel departed from the area near San Francisco's St. Francis Yacht Club. The cause of the sinking remains under investigation.

Boisa's family did not immediately respond to Fox News Digital's request for comment.

Fox News Digital's Michael Sinkewicz contributed to this report.