A floating boom has surrounded a large two-masted sailing vessel that sank over the weekend at its Alameda dock in the Oakland Estuary.

The Kaisei is a replica of a 151-foot brigantine tall ship and is owned by the Bay Area nonprofit Ocean Voyages Institutes, which uses the ship to draw global attention to the problem of marine debris and plastics in the ocean.  

The ship began sinking on Sunday night and a boom around the vessel was deployed Monday afternoon by the Oakland and Alameda fire departments to contain any spilled fuel. The U.S. Coast Guard is working on containment with the National Response Corporation, an environmental cleanup company.

Alameda’s Fire Department responded Sunday, May 25, 2025, to a sinking ship in the Oakland Estuary near the 500 block of Blanding Avenue. The Kaisei is a large, masted vessel. Firefighters and a fire boat worked to protect the surrounding vessels from being impacted and deployed a floating boom to prevent oil spread. (Alameda Fire Department via Bay City News)

In 2009, the crew of the Kaisei, which means ‘ocean planet’ in Japanese, embarked on a month-long expedition to the North Pacific Subtropical Gyre, an area the size of Texas. 

It is the world’s largest patch of floating garbage, compiled by the swirl of global ocean currents. Scientists collected hundreds of samples of marine debris and fish, which were found to contain plastics. Their mission was made into a film called Project Kaisei Expedition.

Ruth Dusseault is an investigative reporter and multimedia journalist focused on environment and energy. Her position is supported by the California local news fellowship, a statewide initiative spearheaded by UC Berkeley aimed at supporting local news platforms. While a student at UC Berkeley’s Graduate School of Journalism (c’23), Ruth developed stories about the social and environmental circumstances of contaminated watersheds around the Great Lakes, Mississippi River and Florida’s Lake Okeechobee. Her thesis explored rights of nature laws in small rural communities. She is a former assistant professor and artist in residence at Georgia Tech’s School of Architecture, and uses photography, film and digital storytelling to report on the engineered systems that undergird modern life.