On a secret mission to explore the California coast, the galleon San Agustin ran aground at Drakes Bay in 1595. Loaded with silk and Chinese porcelain, it foundered in the punishing surf, becoming California's first recorded shipwreck instead.

Now the search is on for evidence of the San Agustin and other disastrous voyages off the coast of the Point Reyes National Seashore.

Federal researchers say they hope to complete a systematic survey of the floor of Drakes Bay within the next two weeks. If the project succeeds, divers could locate and identify as many as 25 shipwrecks spanning the maritime history of the West Coast.

Over the centuries, the bay has claimed local schooners, South American brigs, and lumber ships from the northwest. The underwater wreckage "runs the gamut of vessels that plied the San Francisco coast," said Roger Kelly, an archaeologist with the National Park Service.

The search for these lost vessels was organized by the National Seashore, the Gulf of Farallones National Marine Sanctuary, and the State Lands Commission, which shares jurisdiction of the ocean floor a quarter-mile out to sea.

During the first week of the project, researchers will explore selected areas of Drakes Bay from their boats, using magnetometers to find buried metal, side-scan sonars to get a picture of the sandy floor, and a sub-bottom profiler to reveal the composition and depth of different sediments.

Once promising sites have been pinpointed by global positioning satellites, divers will descend 30 feet below the waves to collect artifacts such as ship fittings, nails, wood splinters, or porcelain shards that can positively identify the wrecks.

While underwater, divers will also test electronic shark deterrents used in South Africa and practice techniques for excavating debris without disturbing the ocean floor.

When the project is completed this fall, federal officials say they will be able to decide whether to plan a major salvage expedition for October 1998 or let the historic vessels remain safely underwater. "The long-term goal is to get data so we can preserve the resources in Drakes Bay," said park superintendent Don Neubacher.

Any artifacts collected from the wrecks may contribute new information about this area's history as an oceanic crossroads, said archaeologist Kelly. Evidence from the San Agustin, he said, could provide details about the construction of the legendary Manila galleon and its fateful last voyage.

"We know more about Roman ships than those galleons," Kelly said. "They were built by experience without using any plans. A splinter would tell us what kind of wood the builders used and where the ship was made."

The project's field director, Larry Murphy, added that historical documents only tell the story of important figures and events, not of the anonymous sailors and commonplace incidents that took place on the high seas. "The only way to get at that," he said, "is to get to the material on the sea bed."

Records show that the Spanish galleon San Agustin, captained by Sebastian Rodriguez Cerme–o, left Manila on July 5, 1595 bound for Acapulco, Mexico under orders to reconnoiter the California coast.

Riding the eastward trade winds for 8,000 miles, the 80-foot vessel reached California in early November of that year. Exhausted, Cerme–o and his sailors anchored the galleon just outside Drakes Estero, leaving part of his crew to watch the ship while they ventured ashore looking for provisions and fresh water.

An unexpected storm arrived from the southwest. As captain and crew watched helplessly, the wind and high seas dragged the 200-ton vessel into the pounding waves, where it splintered and sank in pieces. As many as a dozen crew members died (and a scrap between the Spaniards and the Miwok ensued over the flotsam.)

Empty handed and facing starvation, the remaining party - 70 or so men in all - staggered back to Mexico in an open launch. They left no apparent trace of their visit except a few shards of Ming dynasty china and some iron nails that have turned up in Miwok mounds.

If Cerme–o's expedition had made it further south, he might have claimed an elusive prize; he could have been the European discoverer of the Golden Gate and San Francisco Bay, which he would have claimed for Spain, said Ray Aker, a historian with the Drake Navigators Guild.

"That would have changed the whole history of California," Aker said. "It's significant for what it did not accomplish."

(The huge natural harbor would mysteriously elude almost another two centuries of Manila galleons. Its European discovery came in 1769 by another Spaniard, but by land.)

Aker said the park's project would be successful if, after all these years, it finds any evidence of Cerme–o's failed expedition. But park officials said they have less ambitious expectations.

"If we can verify hot spots as historically significant or as an old refrigerator, that's something," Kelly said.