 Within a year, the NMU had more than 50,000 members, and most American shippers were under contract.Immediately after the NMU's founding convention in July 1937, Curran and other seamen's union leaders were invited by John L. Lewis to come to Washington, D.C., to form a major organizing drive among ship and port workers.The unions comprised by the CIO had been ejected by the American Federation of Labor (AFL) in November 1936, and now Lewis wanted to launch a maritime union.