The Green Star Line was a U.S. steamship shipping line that was created in 1919 and operated until 1923.
During and after World War I, the Shipping Board’s sales campaigns urged Americans to buy ships for wealth and patriotism. Other ethnic groups set up shipping lines by appealing to group solidarity. Irish businessmen created the Green Star Line in response to this need.
Mr. Joseph Mercadante, who led the Nafra Steamship company, became a head of the Green Star Line.
The "Nafra Line", a subsidiary corporation owned and controlled by the Nafra Company, had an enviable record for promptness and efficiency in handling, loading, and discharging ocean-going vessels. The Tidewater and Plymouth were added to the company's initial three vessels and together built a large business. In October 1919, the "Nafra Line" disposed of its vessels to a new organization, the "Green State Steamship Corporation", of which Mr. Joseph Mercadante was also president. This company, which had a capital of $10,000,000, added ten more ships to its fleet and expected to increase it to twenty-two. Mr. Robert McGregor, formerly general manager of the Federal Shipbuilding Company, was vice-president and general manager of the "Green State Steamship Company".
Another subsidiary company of the "Nafra Company" was the "Nafra Stevedoring Company", which performed stevedore work for Nafra steamers at Baltimore. The main ship used for this work was built by Northwest Steel of Portland, Oregon and was launched on 17 November 1919. The ship had been sold to the "Green Star Line" before launching and assigned the name Centaurus. The ship was completed in December 1919, and assigned the United States official number 219283 and Code Letters LTVH.