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Even the most amateur historian is aware of the strategic consequences chronic fuel shortages caused the Germans and Japanese during World War II. But at the operational level, early in the war, the US also face enormous challenges supplying fuel to the fleet in the South Pacific.

The US, of course, had its own robust domestic production of oil, as well as access to large supplies in Venezuala, Aruba, and in the Middle East. The challenge was getting the fuel where it needed to be. The US had to transport crude oil to refineries, and then refined product to England and later the Mediterranean and Europe, and of course, across vast swaths of the Pacific. And to do that, it needed tankers.

Most people are familiar with the stupendous production run of the 10,000 ton Liberty ship. Less well known is the large numbers of tankers built for the war effort.

The iron rule of mass production is to fix an existing design, and build it. That means you are stuck building a design that isn’t the latest and most innovative. But it also means the production learning curve can be quickly mastered.

Prior to the war, the Maritime Commission subsidized the production of several private tankers, with the provision that their design include militarily useful features which otherwise would not have been included for economic reasons. Two such ships, Mobilfuel and Mobilube, were built for the Sconoy-Vacuum Oil Company at the Bethlehem Steel shipyard in 1938-1939.

These 9,900 Gross Rated Tonnage tankers would form the basis for what became known as the T-2 tankers. About 500 T-2s would be build by a host of shipyards during the war. T-2s would come in a variety of configurations, mostly differing in their propulsion plants.  The length of the T-2s might vary somewhat, depending on which yard built them, and what plant they used. The most common variant was the T-2-SE-A1. Four hundred eighty one T-2-SE-A1s would be built. Because of shortages of reduction gearing for steam ships, the A1’s used a steam plant to drive a turboelectric powerplant, with a 7,200 horsepower output, giving the ships a top speed of about 15 knots.

Existing yards didn’t have enough slipways to build the required numbers, so early in 1942, Marinships was formed, and began building a new shipyard in Sausilito. Even as the yard was still under construction, Marinships began building Liberty ships. But soon, Liberty ship production elsewhere was clearly sufficient, and Marinships was tasked to switch to tanker production.

It’s important to note that tankers had three major role. First, tankers were used to transport crude oil from the production fields to refineries. Second, tankers were used to transport refined product overseas. And finally, some tankers were used as oilers, that is, they were used to refuel the fleet at sea. The primary difference between tankers and oilers was that tankers were generally civilian ships with merchant marine crews, whereas oilers were commissioned ships of the US Navy, with Navy crews. They also had the appropriate rigging for underway refueling. Generally, those ships intended as oilers were built with a more powerful 10,000 horsepower plant, giving them a slightly higher top speed of 16 knots.

Marinships, and several other yards, also changed a lot of the way ships were built. We tend to think of shipbuilding as happening on the slipway. But in truth, the major part of ship fabrication takes place in the nearby shops, where plates, piping, wiring and other subassemblies are made. At Marinships (and other yards) rather than just cutting the plating in the shops, and then welding on the ways, major assemblies were built ashore, and then lifted into place on the ways. This approach allowed for specialization. That is, if your job was assembling the deckhouse, that was something you would quickly learn to do, over and over, rapidly. This greatly speeded up construction time. The average production time for a T-2 tanker was only 70 days from laying the keel to sea trials. Marinships actually produced one tanker in only 33 days.

The T-2s also suffered from the stress fractures that plagued the Liberty ships, with several suffering failures.

All of this is a rather lengthy introduction to a fairly interesting, if long, film Marinships put out at the end of the war. Mind you, with the end of the war, there was no more need for a massive shipbuilding program, and Marinships was shut down.