the Age of Sail. They were built to carry bulk cargo for long distances in the nineteenth and early twentieth centuries. They were the largest of merchant sailing ships, with three to five masts and square sails, as well as other sail plans. They carried bulk cargoes between continents. Iron-hulled sailing ships were mainly built from the 1870s to 1900, when steamships began to outpace them economically because of their ability to keep a schedule regardless of the wind. Steel hulls also replaced iron hulls at around the same time. Even into the twentieth century, sailing ships could hold their own on transoceanic voyages such as Australia to Europe, since they did not require bunkerage for coal nor fresh water for steam, and they were faster than the early steamers, which usually could barely make . Ultimately, the steamships' independence from the wind and their ability to take shorter routes, passing through the Suez and Panama Canals, made sailing ships uneconomical. Naval power Until the general adoption of carvel-built ships that relied on an internal skeleton structure to bear the weight of the ship and for gun ports to be cut in the side, sailing ships were just vehicles for delivering fighters to the enemy for engagement. By 1500, Gun ports allowed sailing vessels to sail alongside an enemy vessel and fire a broadside of multiple cannon. This development allowed for naval fleets to array themselves into a line of battle, whereby, warships would maintain their place in the line to engage the enemy in a parallel or perpendicular line. Modern applications While the use of sailing vessels for commerce or naval power has been supplanted with engine-driven vessels, there continue to be commercial operations that take passengers on sailing cruises. Modern navies also employ sailing vessels to train cadets in seamanship. Recreation or sport accounts for the bulk of sailing in modern boats. Recreation Recreational sailing can be divided into two categories, day-sailing, where one gets off the boat for the night, and cruising, where one stays aboard. Day-sailing primarily affords experiencing the pleasure of sailing a boat. No destination is required. It is an opportunity to share the experience with others. A variety of boats with no overnight accommodations, ranging in size from to over , may be regarded as day sailors. Cruising on a sailing yacht may be either near-shore or passage-making out of sight of land