In recent years, monitoring and protecting marine infrastructure have become increasingly critical. Surface marine vessels can provide valuable support in monitoring structures such as offshore wind farms, data cables, and pipelines. Employing surface vessels with ever-increasing autonomous capabilities allows for increased operation efficiency and strategic advantages. In critical infrastructure monitoring, the area of interest is known in advance, and the aim is to detect anomalies. This paper focuses on developing a guidance, navigation, and control framework suitable for a MASS and tailored for critical infrastructure monitoring missions. The primary goals are developing a stochastic-based coverage algorithm to ensure the surveillance of an area of interest and a real-time compliant shadow vessels monitoring system that provides situational awareness of the above-water surrounding environment, detecting threats and unexpected targets over time. The navigation in the operational environment is ensured by an appropriate proprioceptive sensing layer. The hypotheses and the methodologies are shown and explained in detail, together with the preliminary results reporting the first integration. The results are obtained via computer simulations applied to a wind farm critical infrastructure scenario; additional experimental tests are carried out in indoor and outdoor controlled environments to assess the proposed navigation and control systems capability, involving a marine autonomous surface ships test platform available in the university laboratory. The preliminary results demonstrate the ability of the systems to cooperate in the proposed architecture, monitor an Area Of Interest, detect threats, effectively manoeuvre the vessel in real-time, and estimate its state. Such a framework can be further enhanced by extending the perception capabilities for the underwater domain, integrating multiple control logic to allow for more efficient surveillance strategies, or extending the vessel capabilities beyond surveillance missions, adding capabilities like target chasing.