“American tankers cost about $50,000 a day more to hire than foreign vessels, said James Lightbourn, the founder of Cavalier Shipping, a ship financing advisory firm. Using non-American ships could cut transportation costs by about 5 cents per gallon of oil, Mr. Lightbourn estimates. The largest component of gasoline prices is the cost of oil, which has surged around 40 percent since the start of the war, as Iran responded by effectively shutting down oil exports from the Persian Gulf.”