Ukraine has arranged with its partners that it will be receiving warships to ensure the safety of ships in the grain corridor in the Black Sea.
Source: President Volodymyr Zelenskyy, in response to questions from Ukrainska Pravda at the Grain From Ukraine conference in Kyiv on Saturday
My guess is ‘warship’ is doing a ton of heavy lifting in this article. We are most likely talking about something navigable by the rivers routinely used for cargo that move through Europe into the Black Sea.