Monday, 13 June 2016

THE CASE OF THE T2 OIL TANKER PENDLETON.

wikipedia:

The T2 tanker, or T2, was an oil tanker constructed and produced in large quantities in the United States during World War II. The largest "navy oilers" of the period, after the T3s, nearly 500 were built between 1940 and the end of 1945. Many remained in service for decades after the war, and like other World War II ships pressed into peace time service were the subject of safety concerns. A United States Coast Guard Marine Board of Investigation in 1952 stated the ships were prone to splitting in two in cold weather and they were then "belted" with steel straps. This occurred after two T2s, Pendleton and Fort Mercer, split in two off Cape Cod within hours of each other. Engineering inquiries into the problems suggested at first the tendency of the tankers to split in two was due to poor welding techniques. Later, it was concluded the steel used in the war time construction had too high a sulfur content that turned the steel brittle at lower temperatures.

 The T2 was based on two ships built in 1938-39 by Bethlehem Steel for Socony-Vacuum Oil CompanyMobilfuel and Mobilube, differing from the Mobil ships principally in the installation of more powerful engines for higher speed. Standard T2s were 501 ft 6 in (152.9 m) in total length, with a beam of 68 ft (20.7 m). Rated at 9,900 tons gross (GRT), with 15,850 long tons deadweight (DWT), standard T2s displaced about 21,100 tons. Steam turbines driving a single propeller at 12,000 horsepower (8,900 kW) delivered a top speed of 16 knots (30 km/h). 

SS Pendleton was a Type T2-SE-A1 tanker built in 1944 in Portland, Oregon United States for the War Shipping Administration. She was sold in 1948 to National Bulk Carriers, serving until 1952 when she broke in two in a storm. The ship's sinking is the topic of the 2016 film The Finest Hours.

The ship was built at yard number 49 by Kaiser Shipyards, Swan Island Yard, Portland, Oregon.[1] Assessed at 10,448 GRT, 6,801 NRT,[2] 16,643 DWT,[1] she was 504 feet 0 inches (153.62 m) long, with a beam of 68 feet 2 inches (20.78 m) and a depth of 39 feet 2 inches (11.94 m). She was driven by a steam turbine driving an electrical generator, which in turn drove an electric motor that turned the shaft. The turbine was manufactured by General Electric of Worcester, Massachusetts.[2] It could propel her at a speed of 15 knots (28 km/h).

In July 1951, Pendleton ran aground in the Hudson RiverNew York. She was refloated the next day.

On February 18, 1952, while en route from New Orleans to BostonPendleton broke in two in a gale south of Cape Cod.

http://www.uscg.mil/history/articles/pendleton_webster.asp:

The 503-foot, 10,448 gross ton tank vessel Pendleton (T2-SE-A1 or “T2”) was built by the Kaiser Company in 1944 and departed Baton Rouge, LA on February 12, 1952. It was laden with a full cargo of 122,000 barrels of kerosene and heating oil. The ship carried a crew of 41, including the master, Captain John Fitzgerald. Late on the evening of 17 February, Pendleton arrived off Boston. The weather was foul with extremely limited visibility.  The captain opted to stand off and headed his vessel east-northeast at slow speed into Massachusetts Bay into the prevailing sea conditions. The wind and sea conditions worsened throughout the night, building into a full-scale ‘Nor’easter’ gale with snow and high seas.

By 4:00 a.m. on February 18, Pendleton began shipping seas over her stern, but the vessel appeared to be riding well.  Sometime after 4 a.m., the vessel rounded the tip of Cape Cod off Provincetown, MA and assumed a more southerly course.

At about 5:50 a.m. on 18 February, after a series of explosive cracking noises, the Pendleton took a heavy lurch and broke in two.4  At the time of the break, the vessel’s circuit breakers tripped, leaving the bow section without power.  The stern section continued to operate normally, including all machinery and lighting.  


Gone with the darkened bow section were the Captain and seven other crewmen, all destined to perish.  In the stern, the Chief Engineer, Raymond Sybert, immediately took charge and mustered his 32 survivors and assigned them duties.

Alone, adrift, in mountainous seas, the stern section and its human cargo drifted south with a slight port list about six miles off Cape Cod.  The bow section also drifted south, but at a further distance offshore. No S.O.S. had been issued.

Poor welding techniques and brittle steel were thought to be the cause of the Pendleton splitting in two. We know that steel used in the construction of steamers circa 1908 was also high in sulphur content making the steel brittle in cold water conditions. Waratah had taken the ground at Port Adelaide before her final departure to Durban and into history. Captain Ilbery was reported to be visibly and verbally upset about the occurrence stating that his vessel was too heavy (to sustain such forces). One might assume that as a direct result latent hull plate and rivet damage had occurred. Note that the Pendleton had run aground prior to the disaster and might have sustained similar latent hull damage. Winter sea temperatures off Cape Cod range between 10 and 14 degrees celsius. The cold water was identified as being the straw that broke the proverbial camel's (Pendleton's) back. Waratah had come about attempting to return to Durban and left the warmer Agulhas Current, gaining the significantly colder offshore 'Sardine Current', the temperature of which can drop to 14 degrees celsius by late July. It stands to reason that the heavily laden Waratah, subjected to winter dynamic sea forces, notably pounding force (ramming oncoming swells) would have been vulnerable to a similar catastrophe. The sequence of events on the Pendleton was rapid not allowing the crew to send out an SOS message. This might explain why Waratah, prior to the two flashes of light, had not been flying signals of distress. The magnitude of a disaster involving structural failure of the hull could have accounted for Waratah disappearing within two minutes, without any hope of saving souls on board. 

Waratah may not literally have split in two but a significant rent in the hull could have allowed hundreds of tons of water to flood in within a very short period of time.   





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