Four children and three adults were rescued from Tomales Bay on Sunday afternoon after their boat capsized, dumping them into turbulent waters.

Five people, including a 3-year-old boy and 11-year-old girl, were clinging to the overturned hull of the boat when the Sonoma County sheriff's helicopter crew arrived and, one-by-one, plucked them from their perch, Sgt. Ed Hoener said.

During the air effort, rescuers learned that two additional children, ages 6 and 8, were trapped inside the boat's cabin, Hoener said.

A Point Reyes National Seashore marine crew towed the overturned boat into calmer bay waters and Marin County firefighters cut into the hull, finding that the children had survived.

A 46-year-old Elk Grove man was believed to have launched the group, which included a 20-year-old woman and another man, from Lawson's Landing earlier in the day. Officials declined to identify them.

The group apparently was returning when the 25-foot-boat flipped at about 1:20 p.m. in the turbulent waters just outside the bay's mouth, Coast Guard officials said.

Authorities alerted numerous agencies, and emergency personnel began responding by helicopter, boat and car.

The helicopter crew and sheriff's marine unit, who were on patrol in Bodega Bay for the first weekend of crab fishing season, reached the boat within two minutes of the call, Hoener said. They quickly set up a rescue system with Deputy Debbie Little on the end of a 100-foot line.

"The people clinging to the boat were without life jackets. It was treacherous, the water was cold and unforgiving," Hoener said.

Bradley lowered Little down to the boat, she first grabbed the 3-year-old boy, and they dropped him off at Lawson's Landing. Fire crews had not yet arrived, and a "good Samaritan" watched over the child until the fire department arrived, he said.

It took the crew nine minutes to rescue the two children and three adults, Hoener said.

With two children still trapped inside the overturned boat's cabin, Little was lowered onto the boat as was a rescue diver flown in on a Coast Guard helicopter based in San Francisco.

The pair stayed on the boat and communicated with the trapped children as Point Reyes National Seashore boat Recue-29 towed the overturned vessel to Lawson's Landing. "They were tapping back and forth," said Mike Lutz, a spokesman with Coast Guard San Francisco.

At Lawson's Landing, Marin County firefighters cut through the boat's hull and pulled the children out, said Dan Habig, supervising park ranger for the Point Reyes National Park.

They were taken to Petaluma Valley Hospital.

Officials said the seven were extremely lucky and initially feared some involved had died.

"It was a good outcome," said Dan Habig, supervising park ranger for Point Reyes National Seashore.

You can reach Staff Writer Julie Johnson at 521-5220, julie.johnson or on Twitter @jjpressdem.

You can reach Staff Writer Randi Rossmann at 521-5412 or randi.