Hat tip to “Ol’ Petrol Head” for suggesting this.
Liberty ship S.S. Jeremiah O’Brien in San Francisco Bay during Fleet Week, Oct. 2010
The Liberty ships, particularly in the U.S., are generally thought of as being a product of American industrial ingenuity and ability, but the truth is that it was the seafaring British who conceived of the idea.
As was the case in World War I, the Unterseeboot fleet of the German Navy in World War II was wreaking havoc on shipping to and from Great Britain.
The Liberty ships were conceived as a way of offsetting the shipping capacity losses inflicted on the merchant fleet by the U-boats.
The original design was based on plans from the Joseph L. Thompson & Sons yard in Sunderland, England. The plans were very similar to those which had been used to build tramp steamers at Newcastle-on-Tyne since 1879. This style of vessel had been produced until the mid-1930s, the last one being the Dorrington Court. The Liberty ship adaptation was from a wartime plan entitled, “The Northeast Coast, Open Shelter Deck Steamer,” and generally known as “The North Sands 9300 Tonner.” Liberty ships were built in the U.K., the U.S. and in Canada.
The British vessels were designated as Ocean Class ships. Sixty British Oceans were built in the U.S. (30 each at Portland, Maine, and 30 in the Kaiser Shipyards in Richmond, California) with closed shelter deck finish, whereas most of the Canadian construction followed the open shelter deck details and were converted during service. The Canadian-built ships were known as the Park class.
The U.S. Maritime Commission made a number of alterations to the British Ocean design. Some alterations were made to conform to American manufacturing and shipbuilding standards, some to accommodate the scarcity of certain materials, and some to meet the need to build as rapidly and cheaply as possible. The result was designated EC2-S-C1, and they were originally referred to as “emergency ships.”
The standard Liberty Ship, categorized by the Maritime Commission as an EC2 (“Emergency Cargo”) vessel measured between 441 in length, 56 feet in breadth, drew close to 40 feet of water. Liberty ships had five cargo holds, three forward of the engine room and two aft. Each could carry 10,800 deadweight tons. The cargo gear included 5-ton booms for each hold and a 50-ton boom at No. 2 hold and a 15 or 30-ton boom at No. 4. A Liberty ship could carry an amount of cargo equal to four trains of 75 cars each: in addition to the capacity in the five holds, a Liberty ship could carry airplanes, tanks, and locomotives lashed to its deck. In its internal holds, a Liberty could carry 2,840 jeeps, 440 tanks, or 230 million rounds of rifle ammunition.
The engine and hull were developed from British designs – some elements of which were over 60 years old in 1941. Yet, the only significant alteration to the propulsion machinery was the installation of watertube oil-fired boilers to replace the original coal-burning firetube Scotch boilers. Due to a shortage of diesel engines and turbines, the U.S. production of which was designated for its own naval vessels, the Liberty Ships were commonly powered by triple-expansion reciprocating steam engines. The absence of coal bunkers enabled a superstructure alteration, permitting the use of a single structure amidship (rather than two houses). The steam engine pushed the Liberty ships through the water at 11 knots (approximately 13.75 miles per hour). The ships had a range of 11,000 miles.
Early on, many Liberty Ships sailed without defensive weapons. Later, most were equipped with a 3 inch/50 caliber gun at the bow, a 5 inch/38 caliber at the stern, and eight 20-mm guns – two forward, four on top of the midship house and two aft.
The crew quarters were located amidships. The basic Liberty ship was originally intended to have a crew of 45, but this was later increased to include gun crews up to 36, making a crew total of 81. Later the figure was amended, increasing the ships crew to 52 and reducing the gun crews to 29. Each Liberty ship carried a crew of between 38 and 62 civilian merchant sailors, and 21 to 40 naval personnel to operate defensive guns and communications equipment. Amidships on the boat deck, were four steel lifeboats each 24 ft long with a capacity of 25 persons.
The ships have a reputation of having a design weakness in the hull that caused ships to sometimes break in two. The breaking of the hulls was more a result of a combination of brittle steel and harsh Atlantic weather rather than a design flaw. If the steel used in the construction of the ship was not of the correct formulation, the steel could become brittle. When exposed to extremely cold water in harsh Atlantic winter storms, the brittle steel could break. Of the more than 2,751 Liberty ships built in World War II, 52 sank due to fractured hulls.
The Maritime Commission dubbed 27 September 1941, as “Liberty Fleet Day” and launched the first 14 vessels. In his speech at the launch ceremony, Pres. Franklin Roosevelt cited Patrick Henry’s famed speech and stated that the ships would bring liberty to Europe.
In early 1941, the U.S. Maritime Commission placed an order for 260 ships of the Liberty design. Of these, 60 were for Britain. With the implementation of the Lend-Lease Program in March, orders more than doubled. To meet the demands of this construction program, new yards were established on both coasts and in the Gulf of Mexico. Over the next four years, U.S. shipyards would produce 2,751 Liberty Ships. The majority (1,552) of these came from new yards built on the West Coast and operated by Henry J. Kaiser. Best known for building the San Francisco-Oakland Bay Bridge and the Hoover Dam, Kaiser pioneered new shipbuilding techniques.
Operating four ship yards, one in Richmond, CA and three in the Northwest, Kaiser developed methods for prefabricating and mass producing Liberty Ships. Components were built all across the US and transported to shipyards where the vessels could be assembled in record time. The original British design used riveted hulls. Kaiser greatly increased the speed with which the ships could be built by welding the hulls rather than riveting them. The welded hulls had the benefit of streamlining the flow of the ship through the water, increasing the ships’ speed slightly and reducing turbulence compared to the standard riveted-hull vessel. During the war, a Liberty Ship could be built in a about two weeks at a Kaiser yard. In November 1942, one of Kaiser’s Richmond yards built a Liberty Ship (Robert E. Peary) in 4 days, 15 hours, and 29 minutes as a publicity stunt. The first Liberty ship required 244 days to build. By the end of 1945. Nationally, the average construction time was 42 days and by 1943, three Liberty Ships were being completed each day.
The speed at which Liberty Ships could be constructed allowed the U.S. to build cargo vessels faster than German U-boats could sink them. This, along with Allied military successes against the U-boats, ensured that Britain and Allied forces in Europe remained well-supplied during World War II. Liberty Ships served in all theaters with distinction. Throughout the war, Liberty Ships were manned members of the U.S. Merchant Marine, with gun crews provided by the U.S. Naval Armed Guard. Among the notable achievements of the Liberty Ships was S.S. Stephen Hopkins sinking the German raider Stier in September, of 1942.
In 1943, the United States started a new emergency cargo ship program to replace the Liberty ships. The newer ships were bigger and faster with better engines. These ships were designated Victory ships. While the Liberty ships were designed to be the workhorse of the war, Victory ships could continue to be used after the war as part of the regular merchant fleet.
Of all the Liberty ships built in World War II, only the John W. Brown in Baltimore, Maryland and Jeremiah O’Brien in San Francisco remain. Both are museum ships, open to the public for viewing and tours.
The Jeremiah O’Brien on the Sacramento River: