A Contra Costa County sheriff’s boat began taking on water and sank Thursday morning near Bay Point, forcing the deputies aboard to swim to shore, officials said. Around 9:20 a.m., a marine patrol boat was traveling along the shoreline near Bay Point in eastern Contra Costa County when the vessel began leaking at an “uncontrollable rate,” according to Jimmy Lee, a spokesman for the sheriff’s office. The location of the sunken boat was marked with buoys and a salvage crew removed it by Thursday evening, Lee said.