The U.S. Navy is currently developing two new unmanned drone warships, a "large" USV (unmanned surface vessel) a.k.a. LUSV, and a "medium" USV a.k.a. MUSV. The "small" and mine sweeping models are already further along in development.
At this point the details are cloudy:
Autonomy and human-led command and control systems form the basis of the Navy’s rapidly evolving, multi-year “Ghost Fleet” project to engineer a fleet of coordinated, interoperable surface drones able to share time-sensitive combat information in real time across the force. In development now for many years by the Office of Naval Research and Naval Sea Systems Command, Ghost Fleet is engineered to leverage the most advanced AI and machine-learning technologies available. The intent is to enable swarms of synchronized drones to capture, organize and disseminate key targeting and sensor data, such as the location of mines, submarines, surface vessels or incoming enemy attacks.There are not yet hull designs under construction or specific configurations, but the Navy has begun a dialogue with industry to explore technical options and requirements for the new vessels. The service has released a formal RFI - request for information - to industry for the MUSV.
It seems almost inevitable that a large share of all military systems will be replaced by unmanned systems, in the Air Force, in the Navy, in artillery units, and perhaps even in armored forces, transport systems, and medical evacuation roles. They will range from tiny to gigantic. But, nobody has yet worked out how to fit drones into a nation's military in a comprehensive way. There are lots of solid and viable particular drone ideas, but few comprehensive plans that set forth the entire suite of drones that could be used.