The Navy’s proposed schedule for procuring 12 Columbia-class boats, and for having Columbia-class boats replace Ohio-class SSBNs, is shown below. Under the Navy’s FY2012 budget, the first Columbia-class boat was scheduled to be procured in FY2019, and Columbia-class boats were to enter service on a schedule that would maintain the Navy’s SSBN force at 12 boats. The Navy’s FY2013 budget deferred the procurement of the first Columbia-class boat by two years, to FY2021.
As a result of the deferment of the procurement of the lead boat from FY2019 to FY2021, the Navy’s SSBN force will drop to 11 or 10 boats for the period FY2029-FY2041. The Navy states that the reduction to 11 or 10 boats during this period is acceptable in terms of meeting strategic nuclear deterrence requirements, because during these years, all 11 or 10 of the SSBNs in service will be operational (i.e., none of them will be in the midst of a lengthy mid-life overhaul).
The Navy acknowledges that there is some risk in having the SSBN force drop to 11 or 10 boats, because it provides little margin for absorbing an unforeseen event that might force an SSBN into an unscheduled and lengthy maintenance action.