TRIDENT proposes a new methodology for multipurpose underwater intervention tasks with diverse potential applications like underwater archaeology,oceanography and offshore industries, and goes beyond present-day methods typically based on manned and / or purpose-built systems. Trident is based on new forms of cooperation between an Autonomous Surface Craft and an Intervention Autonomous Underwater Vehicle. EU FP-7, ICT Challenge 2: Cognitive Systems, Interaction, Robotics Collaborative Project (STREP), Grant agreement No: ICT-248497 EU Website: http://cordis.europa.eu/fp7/ict/cognition/home_en.html