Bin Laden's Navy

(CBS)  For years, Osama bin Laden and his aides have been known to own ships, but are there enough of them to be considered a private fighting force for terrorism?

According to the Washington Post, U.S. intelligence officials have identified approximately 15 cargo freighters worldwide that have links to bin Laden's al Qaeda terror network, some of which are believed to be bringing in profits for the group.

Government officials, however, are more worried about the possibility that al Qaeda-controlled or linked vessels could be used to ferry operatives, bombs, money or commodities.

It wouldn't be a first, according to authorities who have linked al Qaeda to both the October 2000 attack on the USS Cole - which killed 17 sailors - and the attack two years later on the French oil tanker Limburg.

Both were rammed by small boats.

As for larger vessels, U.S. officials have said that a ship linked to bin Laden was used to transport the explosives that al Qaeda agents used to bomb two U.S. embassies in Africa in 1998.

Ferrying people with al Qaeda links wouldn't be new, either.

In Feb. 2002, according to the Post, eight Pakistanis who jumped ship off a freighter in Trieste, Italy, were found to have links to al Qaeda members elsewhere in Europe. The men - who were arrested on terror conspiracy charges - also had maps of Italian cities, false documents and tens of thousands of dollars in cash.

That seizure, along with many others and numerous searches, is part of what is one of the largest naval seahunts since World War II, according to the newspaper, which says the mission is complicated by ships constantly changing their names, flags and appearances.

Dozens of Navy and allied ships have been paying especially close attention to the Arabian Sea, and post-Sept. 11, have been collecting and analyzing reams of information about the cargo and crew of various ships at sea.

When the information doesn't match up - say, a fishing boat reporting catching fish not typically found in a particular geographic area - the ship gets a visit and a search from authorities.

Making sense of it all isn't easy.

"This industry is a shadowy underworld," one senior official told the Post. "After 9/11, we suddenly learned how little we understood about commercial shipping. You can't swing a dead cat in the shipping business without hitting someone with phony papers."