WWII Tech Pubs Briefing

Written by
James Davies

The SS Stephen Hopkins in action against the German commerce raider Stier on 27th September 1942. Armed only with one 4-inch gun and several lighter weapons the SS Stephen Hopkins was completely outclassed by the Stier, which was armed with six 6-inch guns, torpedo tubes and lighter weapons. The gun commander on the SS Stephen Hopkins (Ensign Willett) was severely wounded early in the battle, but he and his gun crew worked the gun until an explosion demolished the magazine. A cadet (O'Hara) fired the last five rounds single-handedly before the SS Stephen Hopkins sank, taking him and all but 19 of the 55-man crew with her. Only 15 men survived to reach shore. The Stier was set on fire and holed below the waterline during the battle, and she also sank shortly afterwards. An original digital painting by Tim Brown, 1999.

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Overview

In 1936, well over 90% of American merchant shipping was more than 20 years old. In order to ensure that America possessed a fleet that was adequate to meet the future anticipated needs a decision was made to greatly expand America's merchant fleet. The fleet was to be owned and operated by American companies, and in order to ensure their success the American government decided to subsidise the building costs and operating expenses of the ships. As yet there was little urgency in the programme, run by the US Maritime Commission.

In late 1940, desperate for new tonnage to offset losses, British representatives took ship plans to America to try to persuade the American government to let Britain place orders for 60 new ships. The Americans agreed, however no space existed in shipyards to allow them to be built and it was decided to build two new shipyards to meet the British need. These ships bore the prefix ‘Ocean’, with the first ship (the Ocean Vanguard) being launched on 15^th October 1941.

Simultaneous with the decision to build ships for the British was a decision to rapidly expand the US merchant fleet, however the choice of a design appropriate for mass production was a difficult one. The previous ships built by the US Maritime Commission were of a very high quality (but not suited to mass production), in stark contrast to the British wartime designs (which deliberately emphasised speed of construction), and there was considerable resistance to the idea of lowering standards to build ships rapidly. Faced, however, with an urgent need, little time and a sound and readily available design a common-sense decision was taken to adopt the basic British concept for the American emergency fleet. This design was modified somewhat to further aid mass production and to suit American building techniques and other US preferences, and orders were placed for the first 200 of these ships in early 1941.

As with the ‘Ocean’ ships, no shipyards existed to build these vessels and a total of nine new shipyards were announced (including the two required to build the British vessels). Later expansions resulted in even more shipyards, and a total completed fleet of 2,710 ships. It was a project on a massive scale, undertaken with great speed and efficiency. The first Liberty ship (the Patrick Henry) was launched on 27 September 1941 (and completed on 30 December 1941), which was an incredible feat considering that just seven months previously neither shipyard nor workforce existed to build her.

The ships suffered from some initial structural problems, particularly related to the lack of understanding of the influence of welding on the strength of some key elements (such as hatch corners), however once the problems were understood they were soon fixed. Less easy to fix was the 'stiffness' of the ships - they had a rapid roll motion which was uncomfortable for the crew and could lead to damage to cargo. This could be partially offset by putting solid ballast in the 'tween decks, thereby raising the centre of gravity and reducing the 'stiffness'. Unfortunately, if not stowed properly (and sometimes even when stowed properly) this ballast could shift in a storm and put the ship in grave danger of foundering.

A total of 2,710 Liberty ships were completed (with one more being burnt out on the slipway and never completed). This huge total almost defies the imagination when considering the resources that must be employed to produce this number. Putting it in perspective, 1,088 Curtis Hawk fighters were produced (all variants), and approximately 2,900 M16 half-tracks. During the peak building period (March 1943 to December 1943) over 100 were completed per month.

Despite being initially labelled an 'ugly duckling' by the newspapers, and intended to be expendable if necessary, the ships eventually caught the imagination of the public. They proved to be easy to build, reliable and versatile, exceeding even the most optimistic expectations for their overall contribution to the war effort.

The Liberty ship saw service all over the world: they were present in the Atlantic and Russian convoys; they anchored off the beachheads in North Africa, Europe and in the Pacific islands; they carried food to civilians as well as supplies and equipment to the armed forces; as hospital ships they treated the wounded; they transported prisoners away from the fighting; they evacuated rescued Allied prisoners from Asia; in perhaps their most welcome role, they brought the troops home again after the fighting was over.

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Units

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Specifications

Note 1: Draft quoted is maximum normal seagoing draft in peace conditions, and corresponds to the maximum displacement. This draft may be exceeded in coastal or inland waterways, or by overloading during wartime. Unladen ships will have a significantly lower draft.

Note 2: As well as cargo weight, deadweight also includes the weight of stores, fuel and other consumables, although on a cargo ship the 'deadweight' is dominated by cargo weight.

Note 3: Cargo volume is quoted in various measures depending on the type of vessel. The 'grain' measurement is for general dry cargo vessels, and indicates the total volume of the holds, excluding any structural items or fittings (grain fills in all corners and around structural members). The 'bale' measurement is again for general dry cargo vessels, however it measures volume up to the stiffeners on the inside of the hull, with space between stiffeners being lost (bales of cargo don't flow around beams). The 'barrel' is quoted for oil carriers, although in the modern world oil is now normally measured by the ton.

Note 4: The armament provided varied considerably, and could include four inch and three inch guns, 20mm and 37mm cannon, as well as 0.3 and 0.5 inch machineguns. The largest gun (generally a four-inch) would typically be fitted at the stern, and would be flanked by two smaller guns (such as two single 20 mm cannon). There would usually be four gun positions on the superstructure, and these could be 20mm cannons, machineguns, or a mixture of both. The forward mast would be provided with two guns, usually 20mm cannon or 0.5 inch machineguns. On the bow would often be a single three-inch gun. Many variants on this typical arrangement existed, with additional guns being fitted in other areas (such as two or four guns added adjacent to the second mast), or the arrangements changed from those described above (such as replacing the single bow gun with two 37mm cannon).

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