The following is the Dec. 23, 2020 Congressional Research Service Report, Navy Large Unmanned Surface and Undersea Vehicles: Background and Issues for Congress.
From the report
The Navy in FY2021 and beyond wants to develop and procure three types of large unmanned vehicles (UVs). These large UVs are called Large Unmanned Surface Vehicles (LUSVs), Medium Unmanned Surface Vehicles (MUSVs), and Extra-Large Unmanned Undersea Vehicles (XLUUVs). The Navy is requesting $579.9 million in FY2021 research...
https://news.usni.org/2020/12/25/report-on-navy-large-unmanned-surface-and-undersea-vehicles