Losing Norway removes German forward positions against Scapa Flow, Glasgow, and northern Britain. U-boats would have to cross much more of the North Sea while exposed or submerged before reaching their patrol areas, and their return route would face the same danger. Surface raiders would also be observed before they approached the GIUK gap, making that oceanic line a secondary screen rather than the first warning barrier. Allied patrol aircraft, minefields, hunters, and Norwegian coastal observation turn the North Sea into the primary barrier, while Arctic convoys sail away from German operational reach.
Chapter · 29:56-35:43
Denying Norway's bases to German air and sea power
Without Norwegian airfields, fjords, and submarine bases, Germany faces a far more dangerous route into the Atlantic and loses leverage over Arctic convoys.