Naval captain Yuri Lisianskii drew a harbor scene in Alaska about 1805. It was engraved in England for an edition of his book.
In the image, from left to right, there are flags flying on a building, a ship, and a fort. The flag on the building is the simple tricolor of Peter the Great that Russia uses today. The flag on the ship is the ensign of the Imperial Navy. However, after comparing to other Russian flags and the flag of the Russian-American Company, I can't identify the third one.
What's that flag?