USOCAT is a physical (paper) archive and a computerized catalogue of all instances of USO (Unidentified Sumberged Objects) reported in Italy's territorial waters. The obvious difference with UFOs is the environment where the phenomenon seems to show itself: high and low atmosphere for the flying UFOs; the waters of rivers, lakes and seas for the USOs. Given some preliminary problems of definition, after discussion, project co-ordinator chose to single out four categories:

1. objects and lights completly submerged;
2. objects entering water;
3. objects leaving water;
4. objects navigating or standing motionless on water surface.

The present database includes a hundred of entries. A preliminary catalogue has been published as a CISU monograph.