Sergeant Jubert Llewylyn, spokesman for Operation Kingfish, told The Gleaner that 81.5 pounds of cocaine was found on the boat. He said the drug has a street value of J$62 million.
The boat was scheduled to leave for Panama after picking up cargo, Llewylyn said.
Its five-member crew - a German captain and four Filpinos - were arrested and placed in police custody but have not been charged. They eventually returned to the ship where they are being detained.
The ship is being held by the Customs Department.