Concrete Ships: A Strange Maritime History

Concrete is usually associated with bridges, buildings, and roads, not vessels crossing the sea. Yet, during the nineteenth and twentieth centuries, engineers experimented with building boats and ships from this familiar construction material. Some were small craft, while others were ocean-going ships built to carry cargo. This unusual chapter of maritime history grew out of engineering experiments, wartime shortages, and the search for alternatives to steel.

The remains of SS Selma are still visible in Galveston Bay, decades after the experimental tanker was sunk.

How Can Ships Be Made of Concrete?

At first glance, a concrete ship seems impossible. Concrete is heavy, rigid, and commonly associated with structures that stand on solid ground. But a vessel does not need to be made from a naturally floating material. It needs a watertight hull whose overall weight allows it to displace enough water to float.

Concrete ships use reinforced concrete, in which steel bars or mesh strengthen the material. The hull must be carefully designed to withstand water pressure, waves, vibration, and the stresses of movement. The principle is similar to that used in reinforced-concrete buildings, although designing a vessel presents a different set of challenges. The idea was not simply to replace steel plate with solid concrete. Engineers had to develop suitable hull shapes, reinforcement systems and concrete mixtures to make these unusual vessels practical.

The First Concrete Boats

Joseph-Louis Lambot’s Early Experiment

One of the earliest important milestones came in 1848, when French inventor Joseph-Louis Lambot built a small boat using cement mortar reinforced with metal. This construction method became known as ferrocement. Lambot presented his invention at the Paris Exposition of 1855.

His boat was a modest craft, not a giant cargo ship, but it indicated that builders could use cement-based materials to construct a floating vessel. The Encyclopedia of Alabama’s history of SS Selma and the National Maritime Museum of Ireland provide further background on the development of concrete boats. During the following decades, builders experimented with concrete barges and other small vessels. Norwegian engineer Nicolay Fougner later helped demonstrate the material’s potential for larger ships. His vessel Namsenfjord, launched in 1917, became an important milestone in ocean-going concrete ship construction.

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WWII ships made of concrete

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Why Were Concrete Ships Built During the World Wars?

World War I and the Shortage of Steel

The First World War created enormous demand for merchant shipping. Ships were needed to transport food, fuel, raw materials and military supplies, while steel was also essential for weapons, vehicles and other wartime equipment. Concrete offered an alternative for certain vessels. In the United States, the government supported a programme to build experimental concrete ships through the Emergency Fleet Corporation. The programme completed twelve vessels, but they arrived too late to make a meaningful contribution to the war effort. One of these vessels would later become the best-known example of a concrete ship: the SS Selma.

Concrete and World War II

Concrete vessels and barges were also built during the Second World War. However, an important distinction is often missed: not every concrete structure used during D-Day was a ship. The Allied Mulberry harbours constructed for the Normandy landings included enormous reinforced-concrete caissons, which were known as Phoenix units. These hollow structures were towed across the English Channel and deliberately sunk to form protective breakwaters. They helped create sheltered areas where ships could unload supplies. The Historic England account of the Mulberry harbours explains how these concrete structures supported the invasion. They were a major engineering achievement, but they should not be confused with conventional concrete-hulled cargo ships.

On the left is the patented reinforced concrete boat, and on the right is its inventor, Joseph-Louis Lambot.

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SS Selma: The Giant Concrete Ship in Texas

The SS Selma remains one of the most remarkable examples of a large concrete-hulled vessel. Built in Mobile, Alabama, it was launched on June 28, 1919, after the First World War had ended. The ship measured approximately 434 feet (132 metres) long. Its hull was constructed from lightweight concrete reinforced with steel bars, while much of the remaining equipment and machinery used conventional materials.

The Selma entered service as an oil tanker, but its working life was short. On May 31, 1920, it struck a jetty near Tampico, Mexico, damaging its hull. Repairs proved difficult, partly because repairing a large concrete ship required specialist facilities. After spending nearly two years in the Galveston area, the vessel was deliberately sunk off Pelican Island, Texas, on March 9, 1922. You can still see its partially submerged remains in Galveston Bay. The Encyclopedia of Alabama documents the ship’s construction, accident and eventual fate. Its wreck is a striking reminder of an experiment that did not develop into a lasting replacement for conventional steel ships.

Ships made from concrete

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Why Concrete Ships Fell Out of Use

Concrete had some practical advantages. It reduced dependence on steel, could be built using available construction techniques and was useful for certain barges, pontoons and specialised vessels. Ferrocement also became attractive to some small-boat builders. But the disadvantages were significant. Concrete hulls generally required careful reinforcement and could be heavier or bulkier than comparable steel designs. Cracks and serious hull damage were difficult to repair, particularly when suitable facilities were unavailable. Weight, maintenance, and operating requirements all influenced whether a design made economic sense.

Concrete did not disappear from maritime engineering altogether. It continued to be used in floating structures and in specialised marine applications. However, it never replaced steel as the standard material for large ocean-going ships. The wreck of the SS Selma is one of several unusual reminders of abandoned engineering experiments. Readers can also explore RiteBook’s article on incredible abandoned places, which highlights other locations where history has left visible traces.

Fine metal reinforcement is covered with cement mortar to create the hull of a ferrocement boat.

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Frequently Asked Questions

Can ships really be made of concrete?

Yes. Reinforced concrete can form a watertight hull when it is designed and constructed correctly. Concrete boats, barges and larger vessels have all been built.

Who built the first concrete boat?

French inventor Joseph-Louis Lambot built an early ferrocement boat in 1848 and presented his invention at the Paris Exposition in 1855.

Why were concrete ships built during World War I?

Wartime demand for shipping and shortages of steel encouraged engineers to experiment with concrete as an alternative hull material.

What was the SS Selma?

The SS Selma was a large concrete-hulled oil tanker launched in 1919. After its hull was damaged in 1920, it was eventually sunk in Galveston Bay, Texas, in 1922.

Where can the SS Selma be seen?

Its remains lie partially submerged off Pelican Island in Galveston Bay, Texas. Visibility can vary with conditions, and visitors should follow local access and safety guidance.

Were concrete ships used during D-Day?

Concrete vessels and barges were used in wartime roles, but the famous concrete structures associated with the Normandy landings were primarily Phoenix caissons that formed part of the Mulberry artificial harbours.

Are concrete ships still built today?

Concrete remains useful in some marine structures and in specialised craft, including certain ferrocement boats. However, reinforced concrete is not the standard material for modern large ocean-going cargo ships.

Ships made of concrete

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WWII ships made of concrete

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Liberty ships made of concrete

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Construction with cement was quick and straightforward and required poorly trained personnel on ships. Right: one of the boats manufactured by the Ministry of Public Works in 1919.

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Cargo ships were made out of concrete in WW2.

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SS Atlantus is another well-known concrete shipwreck, illustrating the varied afterlives of these experimental vessels.

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Conclusion

Concrete ships may sound like an engineering contradiction, but they were real vessels built in response to practical challenges. From Lambot’s small nineteenth-century boat to the wartime experiments and the remains of the SS Selma, their history shows how necessity can push engineers beyond familiar materials. They never replaced steel ships, yet they left behind an unusual maritime legacy—one that can still be seen in the waters of Texas and in the surviving structures associated with wartime engineering.

References & Sources

• Encyclopedia of Alabama — S.S. Selma 
• National Maritime Museum of Ireland — Concrete Ships
• Historic England — Commemorating D-Day
• Texas Historical Commission — SS Selma historical marker 
• Texas A&M University — The History of Galveston’s Concrete Ships