The procurement of four new-generation submarines to replace the Royal Netherlands Navy’s four in-service Walrus-class submarines has been delayed because discussions with the three competing shipbuilders have yielded less information and less depth than the Dutch Defense Ministry had hoped. (The original bidders for the project were Navantia, Naval Group, Saab Kockums, and Thyssenkrupp Marine Systems, but Navantia was ruled out with an announcement in December 2019.)
The first boat was expected from 2028 and at least two submarines were to be fully operational by the end of 2031 in order for the Royal Netherlands Navy to start phasing out the Walrus class.
Decommissioning two boats to keep the other two submarines operational seems a reasonable interim solution if there are obstacles to keeping all submarines operational. Decommissioned submarines will likely be used for spare parts to isolate and repair defects in active submarines in a timely manner.