The extraordinary reproduction of a Roman transport vessel, anchored in the reconstructed port, stands out in this room and is the thematic axis of this space "Excavating underwater", dedicated to underwater archaeology. This room, curated by the expert director of the CASC, Xavier Nieto, shows all the details of the Roman ship: from its varied cargo, its construction technique, its sails, rudders, bilge pump, etc., to the simple tools available to the sailors. All of this helps the public to understand the complexity and difficulties involved in navigating the Mediterranean in antiquity. The didactic discourse of the room is completed by the reproduction, next to the ship, of the underwater site of a ship sunk in the 5th century AD, which is in the process of documentation and excavation.

The scenography described does not constitute, nor is it intended to be, a mere setting, but has been conceived as a reference and illustration that serves as a support to learn about the documentation and research process developed by archaeologists in underwater sites, governed by a rigorous documentation method that allows the mere archaeological object to become an object of historical value. This complex research process, from the equipment and instruments used in the excavations, to the detailed analysis of the different records and objects found in the archaeological contexts, necessary to be able to identify and date them, make up the powerful database contained in the interactive developed for the room and displayed on a large-format touch screen. This interactive allows the visitor, either individually or in teams, to enter into the investigation and discovery of all the archaeological contexts and objects of the reconstructed wreck, following the same research process developed by the archaeologists.

Unlike the interactives distributed in the permanent rooms, those in this thematic room are not merely informative, but are constructed like "role-playing" games in which the active participation of the visitor is necessary, who, if he or she follows the deductive process of the investigation, will come to know the final result. In the event that the visitor or visitors are not interested in following the proposed game, the interactive has an "animation" window that develops the reconstruction of the sinking of the wreck that is reproduced in the scenography.