The Kaisei, a double-masted ship, sank Sunday at a dock in the Oakland Estuary. A representative for the Coast Guard said a cause was still under investigation. Alameda Fire Department
By Michael Barba, Accountability & Public Safety Reporter
Updated May 27, 2025 (SFChronicle.com)
A ship known for its missions to raise awareness about the problem of marine debris sank Sunday in the Oakland Estuary, authorities said.
The Kaisei, a large double-masted sailing vessel, sank at a dock behind the Nob Hill Foods grocery store in Alameda shortly after 6 p.m., said U.S. Coast Guard Petty Officer Kenneth Wiese, a spokesperson for the agency.
Wiese said the approximately 100-foot ship is owned by the Ocean Voyages Institute. A Sausalito nonprofit founded in 1979, the institute has run ocean cleanup operations, according to its website.
The Kaisei is the namesake of the nonprofit’s Kaisei Project, focused on cleaning the ocean of marine debris, trash and plastics. Though it appears much older, it is a modern replica, previously used as a Japanese training vessel. The ship sailed on three scientific voyages to an area often called the Great Pacific Garbage Patch.
It’s unclear what caused the Kaisei to sink, but officials from Ocean Voyages said in a statement that “the Coast Guard believes that the sinking may have been caused by a something large hitting the vessel.”
Someone on land saw the boat sinking and called the authorities, Wiese said. Multiple agencies, including from Oakland and Alameda, responded and were able to cut its mooring lines so that the ship did not bring down the dock with it.
The ship was not blocking traffic on the channel since it sank in place at the dock, Wiese said. However, it appeared to be leaking an oil-like substance. The vessel is estimated to carry 400 gallons of diesel fuel onboard, Wiese said.
“It looked hazardous,” he said.
An Alameda Fire Department post on X said firefighters on their fireboat had worked to protect surrounding vessels and had deployed a floating boom to prevent oil spread.
Ocean Voyages said efforts to contain spilled oil and gas “have been successful. We are continuing to give our full attention to making sure that all fuel and oil on the ship is removed so that it does not cause any pollution in the waters. Once all of the environmental concerns are addressed, we will be dealing with salvaging the vessel.”
May 25, 2025|Updated May 27, 2025 7:34 a.m.
ACCOUNTABILITY & PUBLIC SAFETY REPORTER
Michael Barba is a reporter covering government accountability and public safety for the Chronicle. He has covered San Francisco since 2015, first as a staff writer for the San Francisco Examiner and later as a senior reporter for the San Francisco Standard. During his time at the Standard, Barba’s reporting led to criminal charges against a building inspector who inspected his own home. He also revealed that Mayor London Breed secretly directed her appointees to sign undated resignation letters, spurring a new law barring the practice. In 2022, Barba was honored by the Northern California Chapter of the Society of Professional Journalists with its Journalist of the Year award. He is a Los Angeles native and a graduate of San Francisco State University. Barba is on Signal at michaelbarba.42.
