The vessel was intercepted by officials with the U.S. Coast Guard, who arrested four suspected drug smugglers, the Coast Guard said in a statement announcing the apprehension.
Crew members aboard the Coast Guard Cutter Valiant, along with members of the Coast Guard Pacific Tactical Law Enforcement Team, launched two small boats to board the 40-foot self-propelled semi-submersible ship on Sept. 5.
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Officials recovered 1,100 pounds of cocaine which was offloaded to the Valiant during operations, the Coast Guard said. The remaining cocaine could not be safely extracted because the submarine was unstable.
"There are no words to describe the feeling Valiant crew is experiencing right now," said Cmdr. Matthew Waldron, the ship's commanding officer, in the statement.
The drug bust is one of several the U.S. Coast Guard has made this month.
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The Coast Guard Cutter Seneca offloaded more than 12,000 pounds of cocaine on Sept. 20 in Miami.
Two other Coast Guard vessels, the Tahoma and the Midgett, were responsible for seizing over 9,000 pounds of the drug earlier this month.
"These down range counter-drug operations are a vital component to the Coast Guard and Department of Homeland Security's mission and our national security," commander of the Seneca, John Christensen, said in a statement.