Why concentrating U-boats on Arctic convoys could backfire

Should Dönitz have concentrated more U-boats against the Arctic convoys?

Probably not; Britain could suspend the route while supplies continued to the Soviet Union through the Pacific and Iran.

A stronger U-boat focus on Arctic convoys would have raised British losses without necessarily achieving Germany's strategic aim. Britain might simply have suspended a route it valued partly for its effect on Soviet morale. Larger volumes of aid could still travel through the Pacific and the Persian Corridor through Iran. The answer distinguishes attacking a visible convoy route from actually severing the enemy's logistical system.