mixture of sea freight and railroad transport. In early 1941, 70,000 barrels of oil were moved on the railroads each day, but this method was expensive, and the bulk of the oil was moved using barges, some with a capacity of up to 15,000 barrels, operating up and down rivers and the Atlantic Coast. With the outbreak of war, the eastern sea routes of the country were attacked by German U-boat submarines. United States naval defence was very limited and largely obsolete; between January and April 1942, among other naval losses, 46 oil tankers were sunk and 16 damaged. The problem was made worse as 50 tankers had been sent to help the UK earlier in 1941. Insurers began to refuse to underwrite the remaining vessels and the volume of crude oil reaching the north-east from the Texas Gulf dropped. In response, steps were taken to better protect the tankers from attack, but losses continued to mount until, in April 1942, they were banned by the Navy from operating the north-east sea routes. The government and industry took steps to maximise the use of the railroads, increasing the amount of oil carried on them more than ten-fold, but there were shortages of rail tank cars, and the existing fleet of cars was in poor condition. Instead, the United States government began to examine options for the use of pipelines to fulfil the demand for petroleum in the north-east. Concept Transporting petroleum by pipeline from the south-west to the north-east was a potentially attractive option for the government as it would be safe from submarine attack and could operate efficiently regardless of the weather. Pipelines had been in use in the industry since 1862, but by the 1930s they were usually only wide, able to deliver 20,000 barrels of oil a day; larger pipes could be built, but due to structural weaknesses they could not operate at the regular pressures. Technologies to build high-pressure pipes at sizes larger than began to emerge during the two decades before the war, but their adoption was not commercially viable. The concept of constructing such a pipeline was first proposed in 1940 by the Secretary of the Interior, Harold Ickes, who argued that "the building of a crude oil pipeline from Texas to the East might not be economically sound; but that in the event of an emergency it might be absolutely necessary". A consortium