Judy Lawson, who fell 500 miles short in her bid to become the first American woman to complete the OSTAR single-handed transatlantic race, has begun a far more auspicious venture.

Lawson recently moved from Annapolis to Thomaston, Maine, to oversee construction of a 44-foot fiberglass sloop in which she intends to race single-handed around the world.

She is the only woman among 33 sailors signed up for the first Single-Handed Round-the-World Race sponsored by the state of Rhode Island, the Goat Island Yacht Club and the (Joshua) Slocum Society.

The race will start Sept. 25 at Newport, R.I., and will be in four stages, with stops at Cape Town, South Africa, Hobart, Tasmania, and Mar del Plata, Argentina. It is expected to take about eight months. In the only similar race ever held--the 1968 Golden Globe, in which the Times of London offered $10,000 for the fastest nonstop solo circumnavigation--nine boats entered but only one finished.

Lawson announced her intention last week at a gathering of sailing buffs in Annapolis. The sailors had convened to see films and slides of her 1980 transatlantic effort, which ended when the mast on her 33-foot sloop snapped in a storm off Nova Scotia.

She was rescued by a passing freighter, but not before her personal spirits sank as she pondered the likelihood of death in her disabled vessel. The film clips, taken by remote control from the cockpit of the sloop, showed her crying, "I just want to survive."

She did, and now she is on to bigger things. Lawson will be 40 years old when the race begins, a veteran of 3 3/4 transatlantics and several trips to Bermuda. She said the OSTAR failure was an eye-opener. "You're almost gone, or anyway you believe you are going to die, and that changes your life forever," she said. "It frees you to do bigger things."

She said she made "at least 474 mistakes" in her transatlantic solo effort, almost all in the preparations. For the round-the-world race, she intends to seek more advice from veteran ocean racers before ever putting to sea.

Her effort will cost $400,000, half that to build the boat, Lawson said. She is seeking corporate and private sponsors.

Said Lawson: "I know I can round up the money. I know it's out there and there is a whole range of interest." She said in addition to seeking a major corporate sponsor, she is accepting individual donations through the People to People Sports Committee, with offices in New York and Washington.

An announcement is expected shortly on an overall corporate sponsor for the race who will provide $100,000 in prizes for the winners. Yachts will be in two classes--44 feet and under, and 45 feet and over.

Lawson's yellow (best for visibility) 44-footer should be completed by the end of April. Lawson will sail her to England in June with Susan Antoniewicz, a cofounder of the local American Women's Offshore Sailing Association. They will race in the 2,000-mile 'Round-Britain race in July and return to Maine for final fitting-out in August.

Lawson expects to be in Newport by Sept. 15 and, fortune and the sea willing, back by the following summer with a world voyage under her belt.