A Soviet 'AGI' intelligence-gathering trawler, nicknamed an 'Ivan' by American sailors, shadows a U.S. Navy carrier task force somewhere in the South China Sea during the Vietnam War. Converted from ocean-going fishing vessels and bristling with antennas, these Soviet ships trailed U.S. carriers on station off Vietnam to monitor flight operations and radio traffic, a routine but tense feature of Cold War rivalry playing out alongside the air war over Southeast Asia. Project: 218012