Because underwater exploration is often a journey as well as the destination.
Basic training covers the safe transportation, storage, use and maintenance of underwater vehicle systems.
Intermediate training steps it up a little to cover safe and effective use of underwater vehicle systems for exploration and observations. Topics include mission planning, deployment checklists, underwater navigation and image data collection.
Advanced training brings it all together to cover external payloads and post-dive data processing for the creation of photomosaics and photogrammetry.