Swedish destroyers make every amphibious approach uncertain

Sweden used its destroyers as part of a wider defensive system. Ragnar, Sigurd, and Vidar had already served through the First World War, yet remained active and viable in the Baltic. Older and newer destroyers moved through narrow waters and archipelagos, changed radio call signs, and operated alongside torpedo boats and aircraft. An attacker could not safely assume which ships were present at a landing point or what supporting threats would appear. Coordination kept an amphibious plan expensive and uncertain. Geography, mobility, and practiced combined defence gave a small navy real deterrent value.