Maintenance delays for U.S. submarines have "resulted in an estimated $3.4 billion in costs to sustain" crews and boats that were not operational.

US Navy attack submarines face significant maintenance delays, costing billions over a decade. A shortage of dry-dock space has led to vessels waiting up to four years for…

While the report said the Navy had made progress cutting delays for operational subs, the problem would get worse — and costlier — for those destined for decommissioning.