ALAMEDA — Emergency and cleanup crews continued fuel containment and safety efforts on Monday at the site of a sailing vessel that sank in the Oakland Estuary next to Alameda.

The Alameda Fire Department spent hours on the scene of a large, masted vessel that sank in the Oakland Estuary Sunday and Monday, the department said.

Fire crews deployed a boom to ensure that diesel fuel doesn’t drift away from the boat.

The state Fish and Wildlife Service and the U.S. Coast Guard took control of the scene on Monday, according to Alameda Fire Department public information officer Kevin Tidwell.

The masts and part of the hull of the sailing vessel remained above the water on Monday. The boat remained alongside the shoreline and wasn’t drifting into the main estuary.

The owner of the sailing vessel has contracted with National Response Corp. to guide containment, safety and cleanup efforts, Tidwell said. National Response provides an array of environmental, industrial and emergency services.

The vessel, called the “Kaisei,” was carrying 400 gallons of diesel fuel on board at the time of the sinking, Tidwell said.

“There are no indications that fuel is leaking,” Tidwell said. “We put in a floating boom. That is still in place, and the vessel is secure.”

Divers were in the water at the sinking site. Other crews were working to remove the fuel from the vessel.

Firefighters worked to protect other vessels in the 2500 block of Blanding Avenue in the estuary from being impacted.

It was not immediately clear what caused the boat to sink.

The Alameda Fire Department asked people to remain behind barriers and away from the sinking site.

“The vessel has tall masts that are leaning toward the shore,” Tidwell said.