A Woodbridge man and his 12-year-old son out on their third sailing trip together got more of an adventure than they bargained for Sunday when a proposed day of sailing on the Potomac River stretched into a 21-hour overnight trip.

Shortly before 9 a.m. yesterday, Thomas N. Wright Jr., 43, and his son Beau were rescued aboard their 16-foot day sailer by Fairfax County fire and rescue personnel.

The two, who had embarked from Pohick Bay Regional Park in Fairfax County shortly before noon on Sunday, were suffering from mild exposure as well as cuts and abrasions from the several hours they spent ashore in a swampy area south of Woodbridge in Prince William County, a Fairfax Fire Department spokesman said.

Camille Wright reported her husband and son missing at 7:30 p.m. Sunday. Two Fairfax County police helicopters and a U.S. Coast Guard vessel searched for the pair until 2 a.m. yesterday, then resumed the search at 8 a.m., joined by two helicopters from the Patuxent Naval Station.

When spotted from the air, the Wrights were sailing northeast toward High Point on the east side of Occoquan Bay. They were picked up by a rescue boat from Fairfax County fire station 20, and their sailboat was towed back to the marina at Pohick Bay Park.

Thomas Wright, a personnel specialist with the U.S. Department of Agriculture, said he and his son spent Sunday night first in a makeshift windbreak ashore, then wrapped in a sail aboard their boat. Wright said he bought the boat after his son attended a sailing camp this summer.

"There was considerably more wind Sunday than we had ever had before," he said. "We started out downstream, and then when we tried to turn around and head back {to Pohick Bay}, the wind and the current were too much."

The two tried first to dock at Featherstone Shores, just south of Woodbridge. About 8 p.m. they managed to get ashore, but found themselves in an impassable swamp.

"The mud was above our knees," Wright said. "We headed north but then we came to a creek we couldn't cross. It was over our heads."

About 11 p.m., according to Wright, he and his son found some boards and erected a windbreak that sheltered them from wind and rain until 2 a.m., when they decided to walk back to their boat. Wright said that he and his son saw the helicopters and the boat searching for them, but that he had no light with which to signal for help.

Wright said he and his son were never really frightened, just frustrated knowing how worried his wife would be.

Beau, a seventh grader at Aquinas parochial school in Woodbridge, "held up pretty well," his father said.

As for their adventure, Wright said: "It just goes to show a lack of experience can get you into trouble. We'll have to reassess the whole thing. But I'm not ready to quit."

He does, however, plan to buy a small motor for his sailboat.