In 1974, the Royal Netherlands Navy announced, through the Ministry of Defence's 10-year plan , that it wanted to replace its aging s. Since the 1960s, the Royal Netherlands Navy had been conducting studies and research into a suitable replacement attack submarine. This research initiative concluded that the Netherlands should build conventional diesel-electric submarines, as nuclear submarines were costly and could only be constructed, crewed, and maintained by countries with major navies such as the United States, France and the United Kingdom. Nonetheless, even with the diesel-electric submarine, the Dutch government sought to work together with international allies to reduce construction costs.