War I to less than 3,000 by the mid-1930s. The revocation of ISU's charter and the loss of 30,000 seamen in July 1937 to the Congress of Industrial Organizations' newly formed National Maritime Union (NMU) signaled ISU's death knell. Leadership of AFL, one of the first federations of labor unions, understood that the ISU was near collapse. The AFL subsequently moved to replace it by issuing a charter to the Sailors Union of the Pacific (SUP) to organize the new Seafarers International Union. Harry Lundeberg, a SUP officer and seaman who was originally from Norway, became the Seafarers International Union's first president. The SUP remained autonomous for years within SIU. The AFL's action to form the SIU not only countered the threat of loss of seafaring jobs to the NMU but also served as a political block against the increasing Communist influence in the rival Congress of Industrial Organizations. NMU, a product of the economic struggles and waterfront strikes of the times, became a longtime nemesis of SIU. The two unions fiercely competed for seafaring jobs until they merged in 2001. The Seafarers International Union membership lagged behind that of the National Maritime Union during World War II. Then Paul Hall started organizing seamen on the East Coast and the Gulf. By 1948, the surge in new membership propelled Hall to the post of SIU vice president. This consolidation helped the SIU edge out the NMU whose earlier purging of Communist Party members or those suspected of CP association had left it weakened. Moreover, Lundeberg's death in 1957 ended a long-running power struggle between Lundeberg and Hall. Heir-apparent Hall subsequently was named SIU president and, later that year president of the AFL–CIO Maritime Trades Department. When Hall took over the Maritime Trades Department, it was a struggling organization made up of only six small unions. He built it into an active and effective political force in the trade union movement. At his death, Maritime Trades Department comprised 43 national and international unions representing nearly 8 million American workers. In 1967, Hall established the Seafarers Harry Lundeberg School of Seamanship in Piney Point, Maryland, to give young people the chance for a career at sea. Since then, the school has become one of the finest maritime training schools in the country. Thousands of SIU members have advanced their skills at the school. Moreover, the Harry Lundeberg School has also presented opportunities