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Precis File
SHIP NAME: Schenectady KEY: NUM. ENTRIES: 3
source USCG 1944 Report
type A
volume
material
dead
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Without warning and with a report which was heard for at least a mile, the deck and sides of the vessel fractured just aft of the bridge superstructure. The fracture extended almost instantly to the turn of the bilge port and starboard. The deck, side sheel and longitudinal bulkhead and bottom girders fractured. Only the bottom plate held. The vessel jack-knifed and the center portion rose so that no water entered. The bow and stern settled into the silt of the river bottom.


source TWI Ltd
type A
volume
material
dead
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At 11pm on the 16 January 1943, a few days after completing sea trials, the 152m long T2 tanker 'Schenectady' broke in two amidships while lying at the outfitting dock in the constructors yard in Portland, Oregon, USA. The temperature of the harbour water was about 4°C and the conditions were still. The air temperature was approximately -3°C and the winds were light. The failure was sudden and accompanied by a report that was heard a mile away. The fracture extended through the deck, the sides of the hull, the longitudinal bulkheads and the bottom girders. The vessel jack-knifed, hinging on the bottom plate which had remained intact. The central part of the ship rose clear of the water so no flooding of the hull through the fracture occurred.

The Schenectady was built by the Kaiser Company as part of the huge World War II emergency ship building programme. This programme produced 2580 Liberty ships, 414 Victory ships and 530 T2 tankers over the years 1941-1946. Although fractures in the emergency programme ships had been reported, the Schenectady was the first catastrophic failure, made all the more impressive by the still conditions under which it occurred. Then, in March 1943, a sister ship to the Schenectady' the 'Esso Manhattan', broke in two at the entrance to New York harbour in sea conditions described as very moderate.

The US Coast Guard, who were responsible for the safety of merchant vessels, requested the setting up of a Board of Investigation into the design and construction of welded ships. The Board was set up in April 1943 and co-ordinated a major research effort into the fracture of ships. The failure of the Schenectady initiated on the deck between two bulkheads. A defective weld was present in a region of stress concentration arising at a design detail. The nominal tensile stress in the deck was calculated to be 68N/mm2. Poor welding procedures were cited by the committee investigating the failure as contributory, however, at the time, the problems were not fully understood.

The importance of weld quality was dramatically illustrated by the experience of the T2 tankers in which 50% of fractures initiated in welds not associated with design discontinuities. The investigation into the 'Schenectady' also questioned the adequacy of steel specifications for all welded ship hulls. The steel used to build the Schenectady was of a quality which was known to be acceptable for riveted ships. The final Report of the Board of Investigation was published in 1946. It considered 4694 welded steel merchant ships built in the emergency ship building programme, of which 970 sustained fractures. The report concluded that the fractures were due to the presence of notches in steels which were notch sensitive at the operating temperature and that the specifications current at the time were 'not sufficiently selective to exclude' such steels.

Research into ship failures continued with the Charpy V notch properties of casualty ship plates being investigated. The absorbed energy in the Charpy V notch test, one of the few standardised fracture tests then available, was found to correlate well with the observed crack initiation, propagation and arrest behaviour of the ship steels. By the early 1950s the 15ft lb or 20J Charpy transition temperature was being used as a reference as it appeared to define the highest temperature at which brittle fracture initiation would occur in ship quality steels. However research showed that the critical temperature for brittle fracture initiation corresponded to higher Charpy energy values when modifications to alloying elements, grain size, deoxidation methods and normalising heat treatments were made. Hence the approach to brittle fracture avoidance could not be based on a simple fixed reference Charpy energy level.

The failure of the Schenectady and other war-time ships gave a significant impetus to the study of brittle fracture. These failures highlighted the influence of temperature on material toughness and the need to specify toughness requirements for welded ships.


source CTX
type L
volume
material
dead 0
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Lane, Ships for Victory has a good photo, p523. The break is just aft of the curved portion of the gunnel aft of the fwd house. Ship has failed in hog. Crack is very clean, clearly brittle fracture.

Despite the clear requirement for a notch toughness spec, most ships are still built largely of Grade A steel which has no notch toughness requirements. Class Rules allow this. See Kurdistan.