For the first time since the design of the first nuclear submarine, the U.S. Navy has no nuclear submarine design program under way, which raises the possibility that design capability could be lost. Such a loss could result in higher costs and delays when the next submarine design is undertaken, as well as risks to system performance and safety. The authors estimate and compare the costs and delays of letting design capability erode vs. those of alternative means of managing the workload and workforce over the gap in design demand and beyond. The authors recommend that the Navy consider stretching out the design of the next submarine class and starting it early, or, if that seems too risky, sustaining design resources at the shipyards, their vendors, and in the Navy itself that exceed those supported by the demand.