​The underwater dimension today represents a geopolitical scenario of absolute strategic importance, where the proliferation of critical infrastructure lying on the seabed, such as submarine data cable backbones and energy pipelines, exposes States to asymmetric and hybrid threats that are difficult to intercept. The protection of these assets requires moving beyond the traditional defence schemes historically entrusted solely to submarines, highlighting the operational need for a dedicated class of surface units.

To respond to this specific defence need, sub-lieutenant Simone Unali developed, in his master's degree thesis, the conceptual design of a new Multipurpose Unit for Surveillance of the Underwater Dimension (UPSDS).

The engineering definition of the platform, developed at the University of Genoa, required the application of the 'design spiral' methodology through a goal-based design approach, integrating civil and military technologies within a reference hull. The study describes a unit with an overall length of 122 metres and a maximum width of 24 metres, characterised by a high degree of payload modularity. The aft working deck and the areas below deck are in fact designed to accommodate standardised modules in a shelter configuration, allowing the rapid loading of autonomous and piloted carriers such as underwater vehicles (UUVs and AUVs), surface vessels (USVs) and tethered systems for great depths (ROVs).

The choice of propulsion architecture fell on an integrated electric propulsion (IFEP) system with two azimuth thrusters which, combined with an IMO DP2 class dynamic positioning system, ensures a maximum speed of 16 knots and high precision in maintaining position up to sea state 3. Electricity generation relies on six diesel generator sets and a lithium-ion battery bank. This configuration allows the introduction of the 'stealth standby' operating profile: the unit can deactivate primary thermal generation to operate in purely electric mode, eliminating the acoustic signature and reducing the thermal signature during passive monitoring. The armament for close counter-drone defence includes a 40 mm remote-controlled gun, two 25 mm machine guns, MU90 torpedo tubes and towed sonar sensors for underwater detection.

The results of the engineering research confirm the technical feasibility of the design, configuring the UPSDS as a capability to guarantee the Italian Navy persistent control of the seabed and the protection of vital interests in the Wider Mediterranean basin.

The author, an officer of the Italian Navy Engineering Corps, specialising in Naval Engineering, obtained a master's degree in Naval Engineering from the University of Genoa on 24 March 2026 and is currently assigned to ITS Duilio​.