Another twist to the case is that Sea Search Armada has presented no physical evidence that it had found the San Jose wreck, only instrument readings. Rather than give one set of coordinates for the ship's location, it filed half a dozen possible sites about 10 miles offshore, thus increasing the area of its claim.
Still uncertain is whether Spain will make its own claim to the ship and its contents under the cultural heritage accord sponsored by the United Nations Educational, Scientific and Cultural Organization. The pact provides that flag vessels and their contents remain the property of the state.
Colombian official Lopez theorized that Spain may be waiting to weigh in until the legal issues are resolved.
Another legal test
On the other side of the Atlantic, a shipwreck site claimed by a Florida-based investor group also is testing the new international legal framework. The so-called Black Swan wreck is thought to contain such riches that a court case is shaping up even before the ship, its location or its nationality have been disclosed.
Odyssey Marine Exploration of Tampa, Fla., announced in March that it had found a wreck in international waters with 17 tons of silver and gold coins and other precious artifacts, providing little additional detail. Odyssey co-founders Greg Stemm and John Morris believe, based on expert examination of the cache, that the treasure could be worth $500 million.
But Spain has challenged Odyssey in U.S. federal court in Tampa, claiming rights to the shipwreck treasure if either it or the vessel turns out to be of Spanish origin.
The case isn't expected to go to trial for nearly a year.
"According to the very limited information that Odyssey has disclosed so far, we believe the shipwreck was located near Cadiz," a Spanish port that was a key departure point for colonial-era Spanish ships, said James A. Goold, a Washington lawyer representing Spain in the Odyssey case.
The coins that have surfaced are gold escudos and silver reales, Spanish coins at the presumed time of the Black Swan shipwreck, Goold said.
Odyssey's founders contend that their discovery of the Black Swan site and importation of its treasure have been legal and in accordance with the U.N. Convention on the Law of the Sea, to which the United States and most seagoing countries belong.
The UNESCO convention on underwater cultural heritage protection, a different accord, is problematic, Odyssey's Stemm said, because "it took the code of ethics of one user group of the resource -- and shipwreck artifacts are a resource -- and ignored all other user groups and constituencies."
Shipwrecks are not of equal historical significance, and their artifacts are not of vital need to national heritage, he argued.
"We need to take a close look at every site and evaluate it on its own merits and significance," Stemm said. "Some sites are going to be very important from the cultural and memorial standpoint, while others are going to be nothing but big piles of coins."
University of Minnesota historian Phillips and NOAA attorney Varmer counter that keeping flagged vessels under state control is a sound principle.
"If you come down on the other side, then the whole world of shipping is up for grabs. That a U.S. Navy ship sinks off the coast of Italy and stays U.S. property makes sense to me in the interests of international law."
Varmer said the United States has not signed the UNESCO cultural accord because it didn't go far enough in guaranteeing nations' access to vessels that sink in foreign territorial waters.
"What is really important is that we acknowledge as a country that the principles are important and that they override private property rights," said Barbara T. Hoffman, a New York lawyer specializing in underwater heritage issues. "The salvors' view has been one of first-come, first-served."
Kraul reported from Cartagena and Williams from Miami.