Newer semi-submersibles are "nearly-fully" submersible in order to reduce likelihood of detection by visual, radar, sonar, or infrared systems.[3]Cargo capacity varies widely with vessel size, although several tons is typical. In 2015, the largest-known cargo of 7.7 tonnes (17,000 lb) was seized on a semi-submersible craft.[5] Some contemporary narco-subs are capable of crossing the Atlantic Ocean.[6]