ANTIOCH -- First responders investigating an overturned boat found floating west in the Delta near Antioch determined it to be a derelict vessel, a U.S. Coast Guard spokeswoman said Saturday.

A Coast Guard vessel and Contra Costa sheriff's office boat and helicopter were circling the 16-foot, white jet boat, which is upside-down, said Coast Guard petty officer 2nd class Pam Boehland.

The officials eventually determined the boat an old junked vessel, she said.

Contact Matthias Gafni at 925-952-5026. Follow him at Twitter.com/mgafni.