Not far along the Powell River in the Canadian city of British Columbia overlooking the Malaspina Strait, ten large ships built in the 1920s and 1940s and later abandoned now form crumbling breakwaters that have long been used to protect ports and A small storage tank for storing tree trunks used by a nearby paper mill, which was once one of the largest paper mills in the world. The characteristic of these huge alignment boats is their material: reinforced concrete.

For a certain period of time, at the end of the nineteenth century and during the more intense world wars, cement was the material used by shipyards around the world, including Italy, for the construction of large and small transportation devices. maritime. This is a choice mainly due to a temporary shortage of raw materials-wood, especially steel, is mainly used in the military industry-and presents a series of advantages.

The use of concrete, which is cheaper and more readily available than steel, during wars can speed up the production time of naval forces and in some cases reduce overall costs. It also eliminates the use of paint and paint as a coating to prevent metal corrosion. This construction technique usually involves the use of overlapping steel mesh frames, which are welded and then combined into concrete to make the walls and hull of the ship.

July 1918, one of the construction phases of a reinforced concrete ship (Topical Press Agency / Getty Images)

The main weakness of reinforced concrete ships is the fragility of the hull in the event of a collision, which in some cases leads to a relative increase in operating costs. In order to reduce the risk of damage, the hull of a large transport ship must be thicker than normal, which results in a reduction in cargo space or a significant increase in the occupied area compared to ships built with traditional materials. Cross section from the ship. This in turn leads to an increase in overall weight and more energy required to move the ship.

The concrete ship "Cretell" shortly after launching at Tilbury Dock, Essex, England in May 1919 (AR Coster / Getty Images)

Reinforced concrete barges appeared in Europe as early as the late 19th century. But the most intensive production phase of the reinforced concrete naval maneuver was during the First and Second World Wars, especially in the United States, where the military ordered the construction of small ocean-going fleets. The largest of these is the SS Selma, a 6,826 gross tonnage, 125 meters long and 16 meters wide, launched in 1919-on the same day as the Treaty of Versailles, the peace treaty that officially ended the First World War-and then briefly Land used as an oil tanker.

Less than a year after launch, it collided with a pier in Tampico, Mexico, causing an 18-meter-long leak in the hull. After temporary repairs and several failed attempts at complete repairs and then reselling, SS Selma was finally abandoned in Galveston Bay, Texas, where it still stands today, partially submerged.

SS Selma in Galveston Bay, Texas (Pixabay)

The oldest known reinforced concrete ship dates back to 1848 and was built by the French inventor Joseph Louis Lambert. This is a small hull, exhibited at the Paris Universal Exposition in 1855. At the end of the 19th century, Italian engineer Carlo Gabellini began to use reinforced concrete to build boats that were thinner and easier to shape.

The ship built by Lambert in 1848 and kept in the museum in Brignoles, France (Wikimedia)

The first cement ship used for ocean voyages was built by the Norwegian Nicolay Fougner in 1917: it was a 400-ton, 26-meter-long ship named Namsenfjord. It was the relative success of the Nansen Fjord that led the U.S. government to commission Fogner himself to conduct a feasibility study on the construction of large ships. On April 12, 1918, U.S. President Woodrow Wilson approved a plan involving the construction of 24 reinforced concrete warships: only 12 were built, and these were already under construction at the end of the First World War.

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The 12 ships planned by the United States were completed, but were subsequently resold to private companies, which used them for raw material storage and commercial shipping. One of them was the SS Palo Alto tanker, which was completed in 1919 and remained idle until 1929, and then deliberately ran aground on the beaches of Northern California. In later years, it became an entertainment venue accessible through the dock (they built On the ship) dance floor and swimming pool) and a tourist attraction, which were finally closed to the public in 1950.

SS Palo Alto near Seacliff Beach in Aptos, California (Naotake Murayama / Flickr)

Another ship, the SS San Pasqual in the early 1920s, was built at a shipyard in San Diego. It was then briefly used as an oil tanker. It was damaged in a storm in 1921 and was not used until 1924. A Cuban company bought it. Molasses was used as a deposit, but it ran aground on the coast of Cayo Las Brujas in 1933 and is still found there today. In the following decades, it was used as a sighting station for German submarines for the first time after being armed; then as a prison for soldiers arrested during the Cuban Revolution in the 1950s; and finally, recently, as a ten-room hotel .

On October 30, 1920, a large freighter named SS Cape Fear, built at a shipyard in Wilmington, North Carolina, sank within three minutes offshore. The fragility of the reinforced concrete hull was miserable from the beginning Obviously. A collision with another ship off the coast of Rhode Island killed 19 crew members.

After the First World War, other more traditional materials and construction techniques were more popular than concrete and could ensure the production of ships that were easier to manage. But in the early 1940s, as the United States entered World War II, many shipyards again used reinforced concrete to make up for contractors’ steel shortages. In addition to building two dozen ships, the US government also commissioned the construction of large reinforced concrete barges, towed by tugboats, for many important military operations, including the Normandy landing.

After the Second World War, the technology of building reinforced concrete ships did not get further development. Many of the existing ones were demolished, others were abandoned, and some were used as breakwaters.

Reinforced concrete boat seen along the Powell River in British Columbia, Canada in 2004 (Wikimedia)

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