A Navy helicopter whipped the waves as the U.S. Coast Guard closed in on the suspected drug traffickers abandoning their homemade submarine off the coast of Ecuador.

The men didn't go down with the ship, but any evidence did.

When authorities confront drug subs on the high seas, trafficking busts turn into rescue operations, the Coast Guard says.

In September, the Drug Trafficking Vessel Interdiction Act of 2008 was signed into law. The statute makes it a felony, punishable by up to 20 years in prison, to travel through international waters in the vessels, technically known as self-propelled semi submersibles.

According to the Coast Guard, the vessels are generally abandoned at sea after delivering their cargo, with cargo values estimated to range from $200 million to $400 million, the investment pays big dividends.

Drug subs come in several forms and are built of fiberglass, wood and steel in the swamps along the west coast of Colombia, under the cover of heavy foliage, Coast Guard officials added.

Federal officials estimate drug subs now transport about one-third of all cocaine that moves by sea from South America to the United States.