Motor oil from sunken Alameda ship found in water as divers continue search for fuel tanks

ALAMEDA, Calif. (KGO) -- Investigators are trying to figure out why a ship that logged more than 40,000 nautical miles sank as it was docked in the Oakland Estuary.

It happened Sunday night near Cal's rowing facility in Oakland and the Nob Hill Foods in Alameda.

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It's an old research vessel that once set sail for the Great Pacific Garbage patch, collecting data to help understand our oceans.

"We're coming home from the airport and my wife said the ship sank, and I'm like what?" said Alameda resident Jon Michels.

"That boat is still submerged and sitting on the estuary floor, it has pretty tall masts that are still leaning," said Kevin Tidwell of the Alameda Fire Department.

Tidwell was there Sunday night as his crew and the U.S. Coast Guard responded.

No one was on board the vessel, called Kaisei, when it sunk. In fact, the Coast Guard tells us it has not moved in eight years.

Sixteen years ago, former ABC7 News reporter Wayne Freedman toured the inside of the ship, before the crew's voyage to the Great Pacific Garbage patch.

As for the current concerns.

"So there was a slight visible sheen after the vessel sunk, which now has been suspected to be from a container of motor oil that was on board the vessel, but not actually from the fuel tanks. At the moment, two of the accessible fuel tanks have been checked by salvage divers from one of the companies that the responsible party has hired; and those two fuel tanks have been found to not contain anything inside of them," said Petty Officer Chis Sappey of the U.S. Coast Guard.

Sappey says there are still three fuel tanks that divers haven't been able to get to, which could be carrying as much as 400 gallons of diesel.

It is not believed that those are leaking and there are now booms surrounding the vessel.

The owners of the ship told ABC7 News the Coast Guard told them that it appears that something large may have struck the vessel causing it to sink.

"There was a current, a pretty strong current at the time of this incident because of the changing tides," said Tidwell.

But as to what specifically could have struck the ship and damaged it enough to sink it, that is unknown at this time.

Ocean Voyages Institute owns the vessel and says once environmental concerns are addressed, they will work at salvaging the vessel.

Ocean Voyages Institute sent us this statement Monday night:

Ocean Voyages Institute confirms that the sailing vessel Kaisei sank on May 25, 2025, while moored in the Oakland Estuary.
The Coast Guard believes that the sinking may have been caused by a something large hitting the vessel.
Our first concern was to make sure that this tragic accident did not cause any environmental damage.
Ocean Voyages Institute, the Board of Directors, and the whole team, want to give huge thanks to the Alameda Fire Department, the US Coast Guard, the State of California Fish and Wildlife division, the Alameda Police Department, and Stones Boatyard.
The Alameda Fire Department put out the first booms around the ship to make sure no fuel or oil escaped the area.
We called in Parker Diving, who put out additional booms. Then NCR Republic have been working removing any oil captured by the booms. Power Engineering is removing all fuel from the vessel.
We are happy to report that currently all of these operations 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.
Kaisei has served as a vital platform for global sail training since 2004, and ocean research since 2009, including expeditions to the North Pacific Gyre in partnership with Scripps Institution of Oceanography and California EPA. The ship's pioneering work laid the foundation for Ocean Voyages Institute's record-setting cleanup operations, including the use of satellite-tagged "ghost nets" recovered by wind-powered vessels.