Building the World's Largest RC Submarinehttps://projectair.co.uk/blogs/articles/building-the-worlds-largest-rc-submarineRCsous-marin
Build an RC Boathttps://www.sciencebuddies.org/science-fair-projects/project-ideas/Robotics_p055/robotics/build-an-arduino-rc-boatarduinobateauboatRC
Build a Remotely Operated Vehicle (ROV) for Underwater Explorationhttps://www.sciencebuddies.org/science-fair-projects/project-ideas/Robotics_p052/robotics/arduino-underwater-ROVarduinoRCROV