Why procure SSNs for regional waters when modern conventional submarines can defend them?
Short answerSSNs provide rapid global redeployment, while SSKs can defend a fixed region more economically and in greater numbers.
NotesA navy may not need an SSN for enclosed or regional waters when a modern conventional boat can perform the local mission. SSKs make sense in the Black Sea, Baltic, Barents Sea, White Sea, and similar operating areas. Nuclear propulsion is most valuable when a small force must redeploy rapidly between distant theatres. A navy defending assets and approaches within one region does not need to pay for that same global mobility in every submarine. The same logic applies to China, where numerous conventional boats could impose a difficult local problem even if an individual SSK is less capable than an Astute- or Virginia-class SSN.