The stakes are high. About 95 percent of the world's commerce, including most crude oil, moves by ship, according to the U.S. National Oceanic and Atmospheric Administration.

Organized Crime Gangs

And pirates prey on all types of ships, from luxury yachts to fishing trawlers to oil and chemical tankers, particularly any vessel with few crew members. (They tend to ignore large cruise ships because of the number of crew.)

Pirates attack with guns, parangs (a machete common in Indonesia and Malaysia) and, on occasion, dynamite. The new breed—decidedly not the swashbuckling pirates of lore—can range from local seamen looking for quick cash to organized-crime gangs and rogue military units.

The most dangerous pirates are gangs toting Uzis and using satellite navigation devices, mobile phones and James Bond-like speedboats. Dressed in black, they board ships at sea in the darkness and take the crew hostage, brutalizing and sometimes killing (with six recorded murders through September).

"Ships are sitting ducks at sea," Burnett says. "It's very difficult to stop pirates these days. Ships and their crews are not equipped to defend themselves."

The ICC-IMB runs the Piracy Reporting Center, a worldwide monitoring agency in Kuala Lumpur, Malaysia, and issues an annual report, "Piracy and Armed Robbery Against Ships." Its Web site tracks piracy week by week throughout the year at Weekly Piracy Report.

Abhyankar notes that "terrorism piracy" has increased near Sri Lanka and the Philippines. The ICC-IMB warns that "virtually every vessel coming within 12 miles of the northeast Somali coast is likely to be attacked."

High-Voltage Fences and Satellite Tracking

Yachts are targets, too. Last year, pirates on the Amazon River gunned down Sir Peter Blake, the yachtsman and environmentalist, after he tried to defend his crew and boat.

"Sir Peter Blake's murder awoke the world to the threat of modern yachting piracy," says Klaus Hympendahl, author of the Pirates Aboard!, to be published next year.

"There's been a steady increase in yachting piracy over the years and many cruisers are now taking a careful look at how to deal with the increased danger," says Herb McCormick, editor of Cruising World.

While private boats can travel in yacht convoys and avoid notorious pirate areas, commercial shipping has no simple safeguard against pirates. Tight time schedules, unchanging shipping routes and the scale of some vessels—like the skyscraper-long oil tankers that are hard to guard against intruders—make it tough to maintain security on the high seas.

An additional invitation to pirates is the shrinking crew sizes as freighting companies automate more shipboard tasks. And the international community has yet to frame a coordinated strategy to combat piracy.

"Less than one percent of those involved in attacks are ever caught," Burnett says. "There are no serious efforts to curb piracy due in part to territorial sovereignty, restrictions against hot pursuit, jurisdictional problems and the lack of superpower or international navies to patrol the high seas and international shipping lanes."

The industry is fighting back. Potential defensive measures include a 9,000-volt electric fence to surround the ship deck, high-powered water hoses to fend off marauders, and a new anti-hijacking satellite system, called ShipLoc, to track a ship's position. So far, international regulations discourage the arming of commercial vessels.

"For now, technology is the best solution, not arms or guns," Abhyankar says.