"The submarines look like they will stay an enigma for a while," said Ralph Wilbanks, the diver who led underwater efforts that found the Confederate submersible Hunley off Charleston Harbor in 1995. "We have looked in the bayou and we didn't see anything we didn't see last time."

Wilbanks, together with fellow Hunley discoverer Harry Pecorelli III and diver Darrell Taylor, spent the last week in February in Shreveport, dragging side-scan sonars and magnetometers in countless lanes on mapped grids on the Red River, Cross Bayou and Cross Lake, looking for nagging mysteries from the Civil War to World War II.

As with Wilbanks' first visit to Shreveport in 1999, the current survey was underwritten by best-selling author Clive Cussler and his nonprofit, volunteer National Underwater and Marine Agency. Cussler said his decision to send Wilbanks and his crew back to Shreveport was based on "new data where the river changed course ... Apparently nothing was found again."

Wilbanks thinks the submarines were abandoned and salvaged after the Civil War.