A memorial turns deadly: What we know about the boat accident near Alcatraz

Authorities are trying to determine the cause of a boat sinking on San Francisco Bay, leaving one person dead and three missing and presumed dead.

Here’s a brief rundown of what happened.

What do we know about the incident?

A group of 20 passengers — mostly family and friends — boarded the boat, called Volare, Tuesday for a memorial service to honor a loved one. After setting out from a marina in the San Francisco Bay Area, they passed under the Golden Gate Bridge to the Pacific Ocean and across the San Francisco Bay to Angel Island.

But as afternoon winds whipped up, the 49-foot recreational cruise boat took on water as they made their way back to shore. It began to sink about 600 yards off of Alcatraz Island at about 3:30 p.m. Some passengers clung to the top deck of the submerged boat while others floated in choppy waters.

Multiple 911 calls came in for a vessel in distress, prompting a massive rescue operation involving the U.S. Coast Guard and the San Francisco Fire Department and multiple partner agencies. Several Good Samaritans also worked to pull people out of the top level of the sinking vessel.

Rescuers scrambled to pull 17 passengers to safety Tuesday afternoon, but one person was pronounced dead upon reaching the shore and three people were transported to a local hospital with injuries from falling into the water. Three passengers remain missing.

What about the search?

The search for the missing was challenged not only by high winds and rough seas, but because the incident took place in a particularly deep channel of the bay dredged for cargo ships, according to Lt. Mariano Elias, a spokesperson for the San Francisco Fire Department.

While most of the San Francisco Bay is less than 30 feet deep, the area where the boat went down was about 130 feet deep. That made it impossible to reach for Fire Department divers, who typically do not venture lower than 60 feet, Elias said.

Officials do not ultimately know if the missing people are with the boat, trapped under one of its three decks, or were swept out to sea. But Jarod Toczko, the U.S. Coast Guard’s San Francisco sector commander, said there was a “high probability” that the missing individuals were trapped inside the vessel.

Survivors, he said, noted that passengers were on the main deck and possibly below deck when it ran into problems.

At 8:30 p.m on Wednesday night, after the U.S. Coast Guard and other agencies searched 950 square miles for a total of 54 hours, the U.S. Coast Guard suspended its active search based on the extensive efforts already conducted and the dwindling probability of locating a survivor.

“Suspending a search is one of the hardest parts of the job and our condolences are with the families of all involved,” Toczko said in a statement on Wednesday evening.

Who was on board the boat?

The party of friends and family boarded the boat for a memorial service. According to the San Francisco Chronicle, they gathered to scatter the ashes of Maria Boisa, a nurse from Fremont who died by suicide in 2015 at age 32.

The man who died was identified Wednesday by the San Francisco medical examiner as Clifford Joseph Boisa, 79, of Sutter County. According to the Chronicle, he was the older brother of John Boisa, 62, who owned and captained the vessel.

A dog aboard the vessel also perished in the incident.

Where is the boat?

The San Francisco Police Department is working with the state Office of Emergency Services to locate the sunken boat.

San Francisco Police Cmdr. Brien Hoo said Wednesday his department is assessing the feasibility of bringing the vessel back to the surface.

Once the boat is located, he said, the department will utilize an underwater drone to assess how structurally sound it is and determine whether they have the capability to raise it.