T2 tanker



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 T-2s, SS Pendleton and SS 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.

T2 design
The T2 design was formalized by the United States Maritime Commission as its medium-sized "National Defense tanker," a ship built for merchant service which could be militarized as a fleet auxiliary in time of war. MarCom subsidized the excess cost of naval features beyond normal commercial standards. The T2 was based on two ships built in 1938-39 by Bethlehem Steel for Socony-Vacuum Oil Company, Mobilfuel and Mobilube, differing from the Mobil ships principally in the installation of more powerful engines for higher speed. Standard T2s were 501 ft in total length, with a beam of 68 ft. Rated at 9,900 tons gross (GRT), with, standard T2s displaced about 21,100 tons. Steam turbines driving a single propeller at 12000 hp delivered a top speed of 16 kn. Six were built for commerce by Bethlehem-Sparrows Point Shipyard in Maryland, only to be taken over by the United States Navy following the attack on Pearl Harbor as the.

T2-A design
Keystone Tankships company ordered five tankers in 1940 from Sun Shipbuilding & Drydock of Chester, PA, based on the T2 but longer and with increased capacity; Marcom would designate this design T2-A. Bigger but faster, they were 526 ft in total length, displaced about 22,445 tons, and were rated at 10,600 tons gross with — yet they attained a top speed approaching 16.5 kn. All five were requisitioned by the Navy during the war and converted to fleet oilers as the Mattaponi class.

T2-SE-A1
By far the most common variety of the T2-type tanker was the T2-SE-A1, another commercial design already being built in 1940 by the Sun Shipbuilding Company for Standard Oil Company of New Jersey. They were 523 ft long, 68 ft abeam, with and. Their turbo-electric transmission system delivered 6,000 shaft horsepower, with maximum thrust of 7240 hp, which produced a top-rated speed of about 15 kn with a cruising range of up to 12600 mi. After Pearl Harbor, the United States Maritime Commission ordered this model built en masse to supply U.S. warships already in accelerated production. 481 were built in extremely short production times by the Alabama Drydock and Shipbuilding Company of Mobile, Alabama, the Kaiser Company at their Swan Island Yard at Portland, Oregon, the Marinship Corp. of Sausalito, California and the Sun Shipbuilding and Drydock Company of Chester, Pennsylvania. During that period, average production time from laying of the keel to "fitting out" was 70 days. The record, however, was held by Marinship, which had the SS Huntington Hills ready for sea trials in just 33 days.

T2-SE-A2 and -A3
The T2-SE-A2 variation, built only by Marinship of Sausalito, was nearly identical to the T2-SE-A1 version, only with maximum thrust of 10000 hp rather than the former’s 7,240. The A3 variation was essentially an A2 built as a Navy oiler from the start, rather than converted later as many A2s were.



T3-S-A1
Despite the confusing T3 designation, the T3-S-A1s built by Bethlehem Sparrows Point for Standard Oil of New Jersey were identical to the original T2s except for having less powerful engines of 7700 hp. 25 of this design were ordered by the Maritime Commission, of which five became Navy oilers as the Chiwawa class.