Police from South San Francisco are searching for a man suspected of kidnapping his own two and three-year-old children and fleeing with them aboard a yacht he stole from an Alameda marina earlier this week. The suspect, 43-year-old Christopher Maffei allegedly abducted his two kids from a home in South city around 3 p.m. on Tuesday.

With the kids loaded into a rented Ford Fusion, police say Maffei drove to Ballena Isle Marina in Alameda, where he boarded the 40-footer called "Unleashed" and apparently sailed north toward Vallejo. The rental car was found abandoned at the marina and the yacht was last spotted around Mare Island up North in the San Pablo Bay at about 6 p.m. on Wednesday. Maffei may have plans to eventually sail out of the Golden Gate, however. According to authorities, he has mentioned in the past that he wants to sail away to Monterey or Mexico.

State, local and federal agencies have all been alerted to watch for Maffei and the missing yacht, but it doesn't seem like there's an extensive search party for the guy or the two kids yet. Still, anyone who spots the yacht, which has "Unleashed" and "San Francisco, CA" painted on it, should alert the South SF Police at (650) 877-8900.

Update: At a press conference this morning, South San Francisco Police said they have located the stolen yacht 50 miles off of Pillar Point near Half Moon Bay. According to NBC Reporter Bob Redell, a Coast Guard C-130 plane is flying over the boat and a USCG cutter is en route to make a rescue.

The Chronicle has more on the investigation: apparently another boater identified the Unleashed this morning from a description put out on marine-band radio. The boater approached the vessel where he "had a short conversation" with the suspect and spotted a small child onboard before leaving the area and alerting the Coast Guard.

Maffei had also been checking out the marina in Alameda for awhile, apparently. He stopped by a few times "dressed like a boater" and inquiring about purchasing several of the boats parked there. The yacht he stole is worth about $250,000, but can only do about six knots, so it seems unlikely that he'll be doing any evasive maneuvers now that the Coast Guard is on to him.