New submarines expand US undersea capabilities General Dynamics Electric Boat and HII’s Newport News Shipbuilding jointly build both submarine classes. For Columbia-class submarines, the central section also contains the missile compartment for Trident II D5 nuclear ballistic missiles. A shortage of experienced workers also pushed submarine costs higher. Long-term investment supports future fleet After two years of talks, the Navy reached an agreement on the final two Block V submarines. In April 2025, it awarded $18.5 billion for the future attack submarines Baltimore (SSN-812) and Atlanta (SSN-813), along with additional funding to support workforce wages.