An English coastal city needs both iron and saltpeter in its Strategic Resource box to build the Man-O-War.
By the middle of the 17th century cannons arrayed along the sides of fighting ships had become the decisive weapon of naval warfare. Heavy guns required a gun deck and a short, sturdy hull, which were at odds with the galley's requirements of lightness and length. The late Elizabethan galleon that became the true man-o-war class reached its culmination in England's Prince Royal of 1610 and the larger Sovereign of the Seas of 1637, mounting guns on three decks; the Sovereign of the Seas, the most formidable ship afloat in its time, carried 100 guns. By the mid-1700s, great ships-of-the-line such as the British Victory and French L'Orient dominated naval warfare, and would continue to do so until the advent of the ironclad.