How do they do it? Basically, it's a big ocean and no one wants to be top cop.
NATO and the U.S. Navy say they can't be everywhere, and American officials are urging ships to hire private security. Warships patrolling off Somalia have succeeded in stopping some pirate attacks. But military assaults to wrest back a ship are highly risky and, to this point, uncommon.
Yet when pirates took their biggest prize to date over the weekend -- a Saudi supertanker carrying $100 million worth of crude oil -- it raised the stakes. The pirates struck hundreds of miles off the coast of East Africa, far out to sea where ships were presumed to be safe.
Governments, navies, oil companies and ship owners are searching for solutions. At least one private security company said it has been flooded with requests from shipping companies for protection, including from Saudis.
Shippers and insurance companies that once minimized piracy's risks -- at worse, pay a ransom, get your ship, crew and cargo back unharmed -- have now awakened to the potential economic effect.
"For a long time I thought this piracy thing was complete nonsense ... isolated incidents being blown up," Giles Merritt, director of the Security & Defense Agenda, a Brussels, Belgium-based think tank on security issues.
Not anymore, he said.
"It's unbelievable to me that we can run AWACS aircraft that can tell you anything that is moving," Merritt said. "But apparently we cannot spot small boats full of chaps with machine guns."
Somali pirates, given free rein in a country with no stable government for two decades, have attacked more than 90 vessels this year and successfully seized 36, everything from ships carrying palm oil and chemicals to luxury yachts. They have raked in millions of dollars in ransoms and are negotiating for more than 14 vessels currently anchored at their strongholds along the coast.
NATO, the U.S. Navy and other militaries say it isn't as easy as sighting a pirate speedboat and intercepting it.
They say their radar does spot pirates on the prowl and they alert crews of threatened ships. But the vast stretch of the Indian Ocean and Gulf of Aden is simply too large. Warships cannot escort every ship and cannot always get to an attack scene in time.
Their focus has been the Gulf of Aden, between Somalia and Yemen, where 20,000 merchant ships a year pass on the way in and out of the Suez Canal, the quickest route from Asia to Europe and the Americas. Three NATO and Russian vessels and up to 15 other warships from a multinational force are patrolling there, along with an unannounced number of U.S. Navy ships.
They have carved out a protected corridor through the Gulf of Aden, and last week the NATO ships engaged in a firefight with pirates attempting to hijack a Danish ship. Still, on Tuesday, pirates succeeded in seizing a Hong Kong cargo ship carrying wheat to Iran.
The capture of the Saudi supertanker Sirius Star opened up an entirely new front farther out in the Indian Ocean -- nearly as far from the Gulf of Aden as Paris is from Moscow. It signaled a threat to another key route, one that rounds Africa's southern tip and is used by vessels too large to traverse the Suez Canal with full cargos.
"Shipping companies have to understand that naval forces cannot be everywhere. Self-protection measures are the best way to protect their vessels," U.S. Vice Adm. Bill Gortney, commander of the Combined Maritime Forces under the 5th Fleet, said after the Sirius Star's capture.
Pirates usually attack in small speedboats, using ropes and ladders to climb aboard and seize the crew. Once they have a ship, military action to free it holds dangers. The pirates are trained fighters, heavily armed with automatic weapons and rocket-propelled grenades, and they have the crews as hostages.
NATO and the U.S. Navy said Tuesday they would not try to intercept the Sirius Star, and its captors took it with the 25-member crew to Harardhere, a pirate den on the Somali coast.
The pirates' strongholds on the coast are well known. But no government has broached the idea of military action to clean them out, reluctant to get drawn into Somalia's chaos. Moreover, a bloody assault could undermine what passes for Somalia's central government, already beleaguered by advancing Islamic militants.
The militants represent another danger. So far pirates have avoided association with al-Qaida militants in Somalia, but that could change. Or, Islamic militants could be inspired by shipping's vulnerability to launch their own pirate attacks.
"If some pirates with a few machine guns are able to hijack a supertanker, you can imagine what al-Qaida could do if it really wanted to," said Olivier Jakob, managing director of the Swiss oil market research firm Petromatrix.
The American military's solution has been to advise ships to hire private security. But many in the shipping industry have been reluctant, fearing armed guards will prompt increased violence from pirates.
So far violence has been minimal. The well-organized pirates have seldom harmed hostages and rarely steal cargos, preferring to release ships for ransoms that some experts say can reach $2 million.
One solution may be unarmed security teams. Using water hoses to batter attacking pirates has worked in the past -- even greasing guardrails so pirates can't climb them can be successful, such firms say.
"We've gotten loads of requests in the last 24 hours from shipowners and managers of the Saudi oil companies to put security teams aboard," Nick Davis, of the Britain-based company Anti Piracy Maritime Security Solutions (Non-Lethal), said Tuesday.
Shipping companies are examining other options, too, including avoiding use of the Suez Canal to stay out of the Gulf of Aden. That means longer, costlier trips around Africa. Odfjell SE, a big Norwegian shipping group, took that step Tuesday, ordering its more than 90 tankers to take the long route.
So far, oil prices are dropping because of the world financial crisis. But if the pirate danger is not handled, that could change, warns Jakob, the oil marketing expert.
"If we were to have a similar type of hijacking on another tanker, I think the markets would take notice," he said.
Associated Press writers Lee Keath reported this story from Cairo and Jennifer Quinn from London. AP writers around the Middle East, Africa and Europe contributed to this report.