The Coast Guard has reeled in a record 355,000 pounds of cocaine over the past year, results that officials say have forced smugglers to transport their drugs through costlier methods like semi-submersible vessels and liquefied drugs.

Coast Guard officials are set to announce Thursday that they seized cocaine with a street value of roughly $4.7 billion in the fiscal year that ended Sept. 30. The previous Coast Guard record for cocaine seizures, set two years ago, was 303,000 pounds. In fiscal 2006, the Coast Guard seized 287,000 pounds of cocaine.

By comparison, the street value of the drugs seized or removed last year by the Coast Guard equals roughly half the agency's total annual budget, said Commandant Adm. Thad Allen.

Officials say smugglers are increasingly turning to more difficult means of moving the contraband from South America. Often that involves so-called "go-fast" boats, which travel far out into the Pacific Ocean hoping to avoid detection, before dropping the cargo in Mexico, and from there it is brought into the United States. Colombia supplies 90 percent of America's cocaine, officials estimate.

"We have forced them to adapt to routes that are dangerous and are expensive. Right now we're seeing guys get in go-fasts and running 1,000 miles into the Pacific and rounding the Galapagos Islands to come in," said Coast Guard Commander Bob Watts. "The fact that we're forcing them to do that is causing them angst, it's causing them pain. That's as much of a win to me on the stretegy side as getting the dope."

White House drug czar John Walters said the results are further proof that seizures have helped drive up the price of cocaine even as the Coast Guard juggles other responsibilities, like homeland security and maritime safety.

"In the context of many other demands on the Coast Guard, they've stayed at the drug problem," said Walters.

Critics of U.S. anti-drug policy say such price increases are only temporary, and do not reflect any significant new advance in fighting drugs.

"When you're looking at proclamations of success and seizure indicators like this, skepticism about the ultimate impact on the market is always in order," said drug policy expert John Walsh of the Washington Office on Latin America, a group that monitors the impact of U.S. foreign policy on the region. "It may be evidence of stepped up or more efficient enforcement, but at the same time it may be evidence of more cocaine being trafficked."

The new drug seizure numbers also come as the Bush administration prepares its final budget plan to present to Congress, and some lawmakers question whether the agency is stretched too thin. Coast Guard officials say anti-drug work is a key part of their homeland security responsibility.

In the cat-and-mouse games between seafaring smugglers and the Coast Guard, technology plays a key role for both sides.

The "go-fast" boats which take long detours to avoid detection need gas to return, so fuel ships often wait for them at some distant point in the ocean. To defeat that method, Coast Guard authorities seek out the gas boats, board them and use chemicals to neutralize the extra fuel.

Smugglers have been helped greatly by global positioning satellites, which make it far easier for someone without much experience to guide vessels at sea.

Such devices are especially helpful for smugglers piloting large semi-submersible vessels, which carry huge quantities of drugs and are virtually impossible to spot at sea because they ride so low in the water.

"Any idiot can use a GPS," said Watts, adding the submersibles "are not new technology but with GPS and satellite phones, if you can get guys that are gutsy enough to do it, they will."

Another smuggling trick is to liquefy the cocaine, making it harder to detect. When the Coast Guard boards a suspected smuggling vessel, they will conduct chemical tests to determine if gas tanks are actually hiding liquid drugs.