Looking at the logs, tried this several times, near the end of the log the AI is always building a boat. (Can’t upload log as new user)
VCMI Version 1.2.1
[2023-Jul-06 22:39:50.032705] DEBUG ai - Trying to realize BuildBoat (value 2.783)
[2023-Jul-06 22:39:50.032716] TRACE ai - Building boat at shipyard Shipyard located at (16 31 1), estimated boat position (18 31 1)
[2023-Jul-06 22:39:50.032726] TRACE network - Sending a request “9BuildBoat”. It’ll have an ID=116.
[2023-Jul-06 22:39:50.032732] TRACE network - Sending a pack of type 9BuildBoat
[2023-Jul-06 22:39:50.032781] TRACE global - We’ll wait till request 116 is answered.