STRUIS BAY, South Africa -- After years of painstaking research and sophisticated surveys, Jaco Boshoff may be on the verge of a nearly unheard-of discovery: the wreck of a Dutch slave ship that broke apart 239 years ago on this forbidding, windswept coast after a violent revolt by the slaves. On the other hand, he may have discovered a wire fence covered with beach sand.

Mr. Boshoff, a 39-year-old marine archaeologist with the government-run Iziko Museums, will not find out until he starts digging on this deserted beach on Africa's southernmost point, probably later this year.

After three years of surveys with sensitive magnetometers, he knows, at least, where to look: at a clutch of magnetic abnormalities, three beneath the beach and one beneath the surf, near the mouth of the Heuningries River, where the 450-ton slave ship, the Meermin, ran aground in 1766.

If he is right, it will be a find for the history books - especially if he recovers shackles, spears and iron guns that shed light on how 147 Malagasy slaves seized their captors' vessel, only to be recaptured.