Why merchant ships carried guns aft

Was the stern placement of merchant-ship guns a tactical choice?

It was principally a legal classification: an aft-mounted gun was treated as defensive, whereas a forward-mounted gun could make the ship appear offensively armed.

The placement was not merely intended to support a retreating engagement. Mounting a gun aft helped preserve a merchant vessel's defensive status, while a weapon forward could be interpreted as offensive armament. That legal distinction imposed a real tactical limitation by leaving the bow less well covered.