Both the navy and coastal artillery were fully mobilized from the first to the last day of World War I. Minefields protecting the coastal fortresses were laid and all forts had infantry protection against coastal attack. The minefields were under army control until 1936 when the control passed to the navy. In 1939, in contrast, the navy and coastal artillery were only partially mobilized, the minefields were not laid, and no infantry protection was provided for the forts.
While the neglect of defenses was serious, it was not total. There was a system of compulsory military service dating back over 300 years. The conscripts were, for the most part, hardy individuals used to outdoor life in a severe climate and most individuals had access to and were proficient in the use of firearms. However, the military training period was short and the equipment was old, if not obsolete. Antiaircraft guns were scarce and there were no tanks and antitank weapons.
Despite these shortcomings, more could have been done after the outbreak of war in Europe with the resources on hand. In addition, quick and resolute actions at the time of the invasion could have made the assault very costly for the attacker. It appears that both politicians and a number of military officials lacked the will to take effective measures.
The Norwegian Army was organized into six divisional areas in 1940. The 1st and 2nd Divisions were located in eastern Norway, the 3rd Division in the southern part of the country, the 4th Division in the Bergen area, the 5th Division in the Trondheim region, and the 6th Division in North Norway. These divisions were not expected to operate in the same manner as those of major powers. The geography of the country dictated a different and more flexible approach. The divisions were territorial in nature and the operational concepts were built around infantry regiments that were expected to operate under the decentralized control of the divisions. The 1st, 2nd, 5th, and 6th Divisions each had three regiments. The 3rd and 4th Divisions each had two regiments. In addition, there were combat units of cavalry, artillery, engineers, and so on. These units were normally parceled out to the regiments, making those units theoretically capable of operating as independent entities. There were three cavalry regiments, three artillery regiments, three mountain artillery battalions, and two named infantry battalions (Alta and Varanger) in North Norway. At full mobilization, the army was expected to field approximately 119,000 men. However, this number gives a false impression. Most of these troops were not trained and the equipment needed to sustain a full mobilization was not available.
Plans for partial mobilization relied on telegrams or letters while full mobilization called for notification by any means, including radio. The depots for the units to be mobilized were located near population centers and this proved to be a serious problem. Five of the divisional areas each had one battalion in training at the time of the invasion, but these units were located some distance from the German landing sites. The 6th Division was partially mobilized because of the Finnish-Soviet conflict, and the area from Narvik to the border with Finland and the Soviet Union can be viewed as reasonably well prepared. The total on duty strength of the Norwegian Army at the beginning of April 1940 amounted to about 13,000 troops and almost half of this force was stationed in the northern part of the country.
Training and exercises of larger formations were two of the most serious weaknesses affecting the Norwegian Army. The lack of maneuvers by larger units resulted in a reduced competence level among the higher-ranking officers in the army, an item noted by the Germans in their after-action reports. A recruit drafted into the infantry served only for 72 days, the shortest training and service period of any country in Europe. In addition, the number of eligible draftees called up each year was continually reduced, first by overly restrictive medical standards, thereafter by a raffle, and finally by the exclusion of several categories of conscripts. By 1940, there were only 20,000 draftees trained to use modern equipment and weapons. It would have taken several years to train the force adequately at that rate. In most respects, except for familiarity with the terrain and experience in the severe climate, the Norwegian Army was poorly prepared to cope with the German Army and its blitzkrieg doctrine.
The Royal Norwegian Navy, including the coastal forts, was partially mobilized at the outset of hostilities in Europe and its primary task was to enforce the neutrality laws and regulations along the extensive Norwegian coast. The navy was divided geographically into three naval districts. The 1st Naval District included the coastline from the Swedish border to a point just south of Stavanger. The 2nd Naval District included the coastline from south of Stavanger to the provincial boundary between Nord-Trøndelag and Nordland. The 3rd Naval District included the coastline from where the 2nd Naval District left off to the Soviet border. The navy was small compared to that in 1914. The total tonnage in 1914 was about 34,600 while the total tonnage in 1940 came to only 10,300. In addition, the construction program in 1914 called for eight coastal defense ships, two monitors, six destroyers, 40 torpedo boats, and 12 submarines. The building program in 1939 consisted of only two destroyers, three torpedo boats, one submarine, and one motor torpedo boat.3
The relatively small navy in 1940 consisted of two coastal defense ships (an additional two in mothballs), 10 minelayers, three older destroyers of the Draug class, four newer destroyers of the Sleipner class, three larger torpedo boats of the Trygg class, and 14 other torpedo boats. There were also six B class and three A class submarines, eight minesweepers, and six patrol ships. Another 49 leased or requisitioned vessels served as patrol boats. A significant portion of the fleet of 111 ships available in April 1940 was obsolete by the standards of the time. Only one minelayer and four destroyers could be considered modern warships. There were 5,200 officers and men on duty in the navy in April 1940.
The coastal fortifications, one of the most neglected elements of the Norwegian defense establishment, were only partially mobilized. Many of the officers earmarked for mobilization had not been on active duty since 1918 and some batteries had not fired a live round since the 1890s. Several of the main batteries were not manned and only a few of the forts had operational antiaircraft guns. The gun-pits were open and exposed to air attacks. The planned minefields were not laid. Under the full mobilization scenario, the coastal forts should have a total strength of 8,424 officers and men. The actual strength in April 1940 was only 2,403.The coastal forts also suffered from a lack of infantry to defend any inland approaches.
There was no Norwegian air force as such. All aircraft were assigned to either the army or the navy. The Army Air Corps was in the middle of reorganization and receiving new aircraft. The period of reorganization and retraining was to have been completed by July 1, 1940. The reorganization called for the establishment of two squadrons of fighters consisting of Curtis Hawk P36s purchased from the United States and two bomber squadrons consisting of Italian Ca 312s. These aircraft were delivered but they were still in their crates when the Germans attacked. Another 129 aircraft were ordered but not delivered.