How would fifteen to twenty improved X1 cruiser submarines change Britain's Second World War?
Short answerImproved successors could add long-range raider hunting, convoy attack, resupply and commando support. Their value would depend on reliable machinery and deployment, with disagreement over the risks and opportunities in the Mediterranean.
NotesA fleet developed from X1 would probably consist of improved X2 successors with reliable powerful diesels. Their long range could allow intelligence-directed attacks on German replenishment ships and disguised raiders, while apparently routine patrols concealed how targets had been found. Deployment creates a disagreement: Mediterranean service could cause heavy losses, although another argument gives the boats a Force K-like role. They could overtake a convoy on the surface at night, dive ahead of it, torpedo the escorts and finish merchant ships with gunfire. Survivors sent east could threaten Japanese invasion traffic, especially the Malaya convoy, where lightly equipped anti-submarine escorts would be vulnerable to heavy guns. Other suggested uses include convoy escort, Malta resupply and commando insertion with supporting gunfire. These are possible missions for an improved class, and their success depends on how the boats are used. A final speculation imagines wartime success encouraging nuclear-powered gun submarines until cruise missiles offer another way to perform the bombardment role.