The first metal ship was launched in 1787, when English industrialist John Wilkinson floated a cast iron barge called “The Trial” on the River Severn in Shropshire, England. From that single experimental vessel, it took roughly 75 years for metal hulls to completely reshape both commercial shipping and naval warfare.
The First Iron Boat: 1787
On July 9, 1787, a large crowd gathered on the banks of the River Severn at Willey Wharfe to watch something most people thought was impossible: a boat made of iron floating on water. John Wilkinson, an ironmaster already known for pushing cast iron into new uses, had built a barge modeled after the flat-bottomed cargo boats common on the Severn. The Trial measured 70 feet long and about 7 feet wide, weighed eight tons unladen, and could carry up to 35 tons of cargo.
The construction was simpler than you might expect. Cast iron plates, each only about a centimeter thick and roughly 3 feet by 1.5 feet, were fastened to a wooden framework and sealed with bitumen for waterproofing. It was a hybrid design, not a fully iron structure, but the hull itself was metal. The Trial proved the basic concept: iron could float and haul freight. Still, decades passed before anyone scaled the idea up significantly.
The First Iron Steamship: 1822
The next major leap came 35 years later with the Aaron Manby, the first steamship built with an iron hull. Fitted with a steam engine designed by Scottish engineer Henry Bell, the Aaron Manby made her maiden voyage in 1822, carrying passengers across the English Channel from London and then up the River Seine to Paris. She averaged 8 to 9 knots, a respectable speed that demonstrated iron and steam power could work together for practical, scheduled transportation.
This was a turning point. Wooden steamships already existed, but their hulls struggled with the vibration and weight of increasingly powerful engines. Iron hulls solved both problems. They were stronger under stress, lighter relative to the size of ship they could support, and far more resistant to the constant shaking of a steam engine. The Aaron Manby made the case that the future of powered shipping would be built from metal.
Crossing Oceans in Iron: The SS Great Britain
The ship that truly proved iron could dominate long-distance travel was the SS Great Britain, launched on July 19, 1843, and designed by the legendary engineer Isambard Kingdom Brunel. She was the first iron-hulled, screw-propelled ship to cross any ocean, making her first transatlantic voyage to New York in 1845.
Brunel packed the Great Britain with innovations that became standard in shipbuilding for the next century. Her 1,500-horsepower engine used a chain drive system. She had watertight bulkheads (internal walls dividing the hull into sealed compartments, so a breach in one section wouldn’t sink the whole ship), a double bottom for extra protection, a balanced rudder for better steering, and even an early electric speed log. The compartmented hull design alone was a safety revolution, one still used in every large vessel today.
The Great Britain’s success opened the door for Britain’s dominance in global maritime commerce through the late 1800s. Once shipbuilders saw that an iron ocean liner could reliably carry passengers and cargo across the Atlantic, wooden ocean-going vessels were on borrowed time.
Iron Warships Change Naval Warfare
Military navies were slower to adopt iron hulls, partly because admirals worried about iron shattering into deadly shrapnel when hit by cannonballs (wood splintered, but iron fragmented differently). France forced the issue in 1859 by launching the Gloire, the first ocean-going ironclad warship, though she still used a wooden hull underneath her armor plating.
Britain responded immediately. HMS Warrior, launched on December 29, 1860, was the first warship with both an iron hull and iron armor plating. She and her sister ship HMS Black Prince made every wooden warship in the world obsolete overnight. No wooden vessel could match their combination of speed, firepower, and protection.
The moment that sealed the transition came during the American Civil War. On March 9, 1862, two ironclad ships, the USS Monitor and the CSS Virginia, fought to a draw at Hampton Roads, Virginia. They fired on each other all morning, and their armor plates deflected every shot. No wooden ship could have survived that exchange. Navies around the world watched and drew the obvious conclusion: the age of wooden warships was over.
Why Iron Replaced Wood
The shift from wood to iron (and later steel) happened because metal solved nearly every limitation wooden ships faced. Iron hulls were far stronger, allowing shipbuilders to construct vessels many times larger than the biggest wooden ships. They held up better in storms and rough seas, where wooden hulls could twist, leak, or break apart. And they could support the weight of larger engines, heavier cargo, and taller superstructures without compromising the ship’s integrity.
There were practical advantages too. Wooden hulls rotted, attracted marine worms that bored through the planking, and needed constant maintenance. Iron hulls rusted, but that was easier and cheaper to manage. As steel production improved in the 1870s and 1880s, shipbuilders switched from iron to steel, which was even stronger and lighter. By the 1890s, virtually every major commercial and military vessel was steel-hulled.
The full timeline from first experiment to industry standard spans roughly a century: The Trial in 1787, the first iron steamship in 1822, the first ocean crossing in 1845, the first iron warships in 1860, and near-total adoption of steel hulls by the 1890s.