Naval Station Key West was decommissioned in 1974 as part of post-Vietnam War force reductions .
The U.S. Navy had decommissioned nearly all of their diesel - electric submarines and contemporary nuclear powered submarines were too large for the station 's existing port .
Naval Station Key West was decommissioned in 1974 as part of post-Vietnam War force reductions because the U.S. Navy had decommissioned nearly all of their diesel - electric submarines and contemporary nuclear powered submarines were too large for the station 's existing port .