&gt; <i>It&#x27;s really surprising that turtle ships and detonating fire ships weren&#x27;t more commonly used.</i><p>I can&#x27;t speak for the turtle ships, but the cost of the gunpowder used in a hellburner can&#x27;t be overstated. I know that in the 18th century British navy, accurate gunners were at a premium because the government would not supply powder and shot for target practice, and only a wealthy captain could afford to purchase enough for really good training. The military cost of widespread incompetence at gunnery was deemed less than the financial cost of those training supplies--and that was more than two centuries of development after the Antwerp hellburner.