With the approach of the 500th anniversary of Columbus' 1492 landfall in the New World, researchers are reviving an old debate about exactly where in the Bahamian archipelago the admiral first stepped ashore.

A year ago National Geographic magazine claimed to have found the right answer -- Samana Cay, also known as Watling Island, about 130 miles southeast of the traditionally cited San Salvador.

Now a team from the Woods Hole Oceanographic Institution (WHOI) asserts that Geographic's methods were flawed and that its own superior methods point to San Salvador after all.

Geographic's case, argued by editors Luis Marden and Joseph Judge, rests heavily on a day-by-day plotting of Columbus' log, which gives compass headings and estimates of distances traveled, onto a chart of the Atlantic with corrections for winds and currents.

It was the corrections, Marden and Judge said, that led the track to Samana Cay. The WHOI researchers say that incorrect corrections led Marden and Judge astray.

Writing in the WHOI magazine, Oceanus, Philip L. Richardson, a specialist in Atlantic currents, and Roger A. Goldsmith, a computer specialist, claim Geographic used the wrong current speeds in making their corrections. Marden and Judge relied on numbers given in modern pilot charts, but Richardson and Goldsmith say these are about three times larger than Columbus probably encountered.

Also the WHOI researchers say that while Geographic was right to apply wind corrections for the first part of the journey where the northeast trade winds pushed Columbus south, they failed to make proper corrections for the last part, where the southeast trade winds would have pushed him back north.

After making what they feel to be correct adjustments to the log, the WHOI pair say they have "the best reconstruction of Columbus' first voyage of discovery to date."

The new claims are certain not to settle the debate, which includes advocates of two other purported landing sites -- Grand Turk Island to the south, and Egg Island to the north. The debate may never be settled because of one major factor that all parties have had to ignore -- magnetic variation. Earth's magnetic poles shift continually, so that compass needles point in slightly different directions from year to year and corrections must be made. No one knows how extreme the variation was in 1492.