Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Furnishings and Equipment (hierarchy name)
4. Transportation Vehicles (hierarchy name)
5. vehicles (transportation)
6. watercraft
7. [watercraft by specific type]
8. [watercraft by operating environment]
9. [watercraft by displacement]
10. subsurface watercraft
11. submersibles
12. unmanned underwater vehicles

Anotations

Scope note:

Remote underwater free-swimming vessels distinct from remote control vehicles that operate in the air or on land. ROVs are unoccupied, and are tethered to operators that maneuver them from vessels, floating platforms, or on land. They are common in deep water industries, underwater archaeology, and marine biology. They are linked to a host by buoyant tethers or load-carrying umbilical cables.