When most new U.S. warships began carrying their missiles in vertical cells in the 1980s, a crane (the "strikedown crane") was included so the cells could be reloaded at sea. But new models of the missiles became too heavy for the strikedown crane and it wasn't practical to install a larger and more powerful crane. Moreover, there were few opportunities for reloading the missile cells at sea anyway. So the strikedown crane is being omitted in new ships. This provides space for 3-6 more missile cells.