A ship called Liberty

The longest campaign of the Second World War was one that is frequently overlooked. Unglamorous and lacking in easy-to-grasp decisive moments like a Midway or a D-Day, the Battle of the Atlantic started on the first day of the war and continued to the last day without pause. Over 3,500 Allied merchant ships were sunk at a rate approaching two per day, along with 175 of the warships tasked to protect them, at a total cost of over 30,000 sailors’ lives. On the German side of the equation 783 U-boats were sunk and 27,000 crew killed – 75% of those who served. This was the highest fatality rate of any combat service in World War Two.

The terms of the engagement came down to what became known as the tonnage war. If the Axis Powers could sink ships faster than they could be replaced, they would win the war. This was because although the Allies undoubtedly had superiority resources once the United States entered the war, these could only be brought to bear if they could cross the ocean. This fact made the stakes in the Battle of the Atlantic incredibly high. As one British admiral put it, “if we lose the war at sea, we lose the war.” But fortunately, the Allies had an ace up their sleeve. Not an astonishing new weapon, nor a brilliant tactical ploy, but a simple, and rather ugly looking ship.

The concept of what would become Liberty ships started life in Britain. Concerned with the loss of merchant shipping to the U-boats, the Government commissioned Sunderland shipbuilders J.L. Thompson to come up with a large (10,000 ton), quickly built and cheap to operate freighter in 1940. The resulting design was called an Ocean-class. The accommodation, bridge, and main engine were all located amidships in a single central unit with a long tunnel connecting the main engine shaft to the propeller. The engine was a triple expansion steam engine - an outdated but reliable design. They were also specified to run on coal, Britain having extensive domestic reserves. When the design was complete sixty were ordered from US yards, and the first, the SS Ocean Vanguard, was launched on 16 August 1941.

With war approaching, the United States Maritime Commission were also looking for a large, simple cargo vessel. Since the US’s entire capacity for turbines and marine diesel engines was allocated to warship production, the benefits of the British ship with its older design of engine was obvious. The Americans made a number of modifications to the Ocean-class, most of which made it even quicker and cheaper to build. Riveting was replaced wherever possible with welding; oil lamps replaced electrical lighting to save on complex wiring looms, and oil-fired boilers replaced coal ones. Production was awarded to a conglomerate of companies headed by Henry J. Kaiser, who proved to be an inspired choice.

The ships initially had a poor public image owing to their box-like appearance. Time Magazine called them "Ugly Ducklings” and even President Roosevelt referred to them as "dreadful looking objects” in a speech announcing the emergency shipbuilding programme. But at the launch of the first ship, named the SS Patrick Henry after the American patriot who demanded "Give me liberty or give me death", Roosevelt said the new ships would bring liberty to Europe, and thereafter they were known as Liberty ships.

Henry Kaiser organised the production of Liberty ships in truly astonishing numbers. The ships were made assembly-line-style, from prefabricated sections. The extensive use of welding meant that many women could be employed in their construction. In 1943, when production reached its peak, three Liberty ships were completed daily. One ship, the SS Robert E. Peary, was launched 5 days after the keel had been laid as a publicity stunt, although much fitting-out work remained to be done after she was launched. By the end of the war 2,770 Liberty ships had been launched, the majority made in US yards with others built in Canada and the UK. The total tonnage of these ships came to just under 30 million. To put that in perspective, total allied shipping tonnage lost in the whole war was under 22 million.

There were many factors that turned the Battle of the Atlantic in the Allies favour. The brave sailors and airmen that guarded the convoys and hunted down the U-boats were foremost. Technological advances in radar, sonar, weapons and codebreaking played their part too. But surely it was the remorseless industrial muscle applied by American industry to the production of Liberty ships that guaranteed that the U-boats could never win.