According to the footage, the Marichka is a black-colored unmanned underwater vehicle (UUV) with a length of 6 meters and a range of about 1000 kilometers. It can perform attack, transport or reconnaissance missions.
Ukraine's new underwater drone Marichka breaks cover - Naval News
Navy NewsThis one is right up my tree.
Ukraine’s New Underwater Drone Marichka Breaks Cover
On August 23, 2023, several Ukrainian accounts on social media released a video showing Ukraine's new underwater suicide drone named "Marichka".
Tayfun Ozberk 23 Aug 2023
Some ying and yang in this. The Tech exists. 10km I would think possible. 1000 is a bit of hype I assume.
Some modem torpedoes have a effective range of 7000m with cruising extending that to 10,000m or 10km. Have to add naviagtion underwater is not as simple as most would assume. active Sonar is one of the most effective yet it also scream HERE I am to anyone with an ear in the water
10km is almost over the horizon for larger vessels . It is for close to the water or underwater one. Reportedly "Black Sea fishing fleet—some 71,400 vessels" That is a LOT of ways to get within 10km
"The meaning of Marichka may be Ukrainian version of Maria, meaning star of the sea, bitter or beloved."