As maritime and military missions become more and more complex over the years, there has been a high interest in the research and development of Unmanned Underwater Vehicles (UUVs). Latest efforts concern the modeling and simulation of UUVs collaboration within formations of vehicles (swarms), towards obtaining deeper insights related to critical issues related to cybersecurity and interoperability. The research issues which are constantly emerging in this domain are closely related to the communication, interoperability, and secure operation of trustworthy UUVs, as well as to the volume, velocity, variety, and veracity of data transmitted in low bitrate due to the medium i.e., the water. This paper focuses on such issues in the domain of UUVs, emphasizing interoperability and cybersecurity in swarms of trustworthy UUVs in a military/search-and-rescue (SAR) setting. The aim of this paper is to present preliminary work on a semantic modeling and simulation approach that aims to facilitate commanders of military/search-and-rescue operations to effectively support critical and life-saving decision-making, while handling interoperability and cybersecurity issues on the Internet of Underwater Things (IoUT).