It would be good to capture the admiral instead of killing him.
But it seems better to try heading southwest, approaching from the stern of the large ship (which won't be able to turn around and catch up), and shooting down the small ship on the west that tries to interfere.
Or take advantage of your engine and reverse, which would shock everyone. But only if the speed loss from such a maneuver isn't too great.
Too bad you don't have mages with Fireball...