Odderøya has been fortified with military facilities since the 17th century. See a separate map of the various redoubts and batteries that have been on the island.
Militarily speaking, Odderøya had its military heyday in 1905 and during the neutrality watch during the First World War. The island was then equipped with modern cannons and fortifications of the time. Fully manned, Kristiansand Fortress was to have 250 officers and 1,200 privates. The fortress organization also included the battery and minefield in Marvika/Gleodden, guard vessels and observation posts in Randesund and on Flekkerøya. The fortress then had a Main Battery with 2 x 21cm guns, 3 batteries with 2 x 15cm guns and 1 Howitzer Battery with 4 x 24cm guns. As well as Eastern beach battery which had 2 75mm guns. In Marvika were 3 15cm guns, 2 75mm guns and a minefield (which was to be laid from Gleodden to Smeholmen).
Throughout the ages, there have been eras where the Armed Forces were given a lower priority. This also applied to Kristiansand Fortress, which was placed in reserve in the 1920s. This meant, among other things, that not enough personnel were trained. No exercises were carried out and the equipment was only slightly maintained. This was a deliberate policy, Det Brukne Gevær. This deprioritization of the Defense Forces and the coastal fortresses had disastrous consequences on 9 April 1940. Although they fought a heroic battle on Odderøya and drove the Germans back twice, they would not have been able to stand against the superior force for longer than they did. The German invasion force was let through unhindered on the 3rd invasion attempt because someone from the fortress mistook a signal flag for the French flag. 8 were killed and approx. 40 injured during the attacks which lasted from 0500 to about 1130.
During the war, the Germans moved the best guns to Randøya and Flekkerøya and some further west. The howitzer battery was left behind and was fired at once. They moved Cannon 2 to Western Battery and established a communications center in Cannon 2's ammunition magazine and cover room. Odderøya was used by the Germans as a recruit school. They built a number of barracks and improved the road network. Likewise, they built two gun emplacements in the south of the island for some armored guns. These were dismantled in the 1960s.
The howitzer guns remained, without being used, until the mid-1950s when they were sold as scrap.
In 1945, a 2-cannon battery of the 10.5cm K33 type was installed on Odderøya in the former Middle Battery. The measuring station and command post were in the former main battery's command post.
In the early 1950s, the cannon was replaced with x-German 10.5cm SKC/32 and in 1961 the 3rd cannon was mounted in Eastern Battery.
The battery's task was to protect the minefield that was to be laid between Grønningen and Oksøy lighthouse in the event of an armed conflict. The battery was also supposed to be able to provide artillery support to the neighboring forts Randøya and Krossodden (on Flekkerøya). The cannon had a rate of fire of approx. 17 shots per minute and the firing range was 15,000 metres. From 1985, old ammunition was replaced with modern ammunition that was more effective against vessels than the old x-German ammunition. The battery was closed in 1994.
The coastal artillery's organization on Odderøya
After the war, there were 5 cohorts that had not been in for initial service and an intensive training of commanders who could train these large cohorts of soldiers was initiated. One had for periods herds on Odderøya, Randøya and Flekkerøya. The initial service was initially 16 months, then 12 and at the end (1993) 9 months. Kristiansand Fortress changed its name to Kystartilleribrigade Sør then back to Kristiansand Fortress. In 1962, the Coastal Artillery transferred to the Norwegian Navy and the name of the fortress was changed to Norwegian Naval Command Sørlandet and after a few years became known as Southern Naval Defense District, a name they kept until the closure in 2000.
On Odderøya, in addition to a recruit school with 1,000 soldiers a year right up until 1993, the Naval District's management and operations department as well as personnel and station departments had a large workshop organization which consisted of, among other things, an artillery workshop, searchlight workshop, exchange maker, servo workshop, carpentry workshop, plumber, welding workshop, painting workshop and a sanitation department and transport department, car workshop, tailor, shoemaker as well as a sanitation department and welfare office. In 1905 there was also a bakery and pub on the island. Many warehouses housed equipment, weapons and ammunition for the mobilization departments.
The task of the district was to keep plans up to date, maintain material and equip the war crew, which numbered 3,000 men.
In the 1950s, the Naval District's communications department was located in an extension to the Commander's Residence. Later, the department was moved to the basement floor of the administration building and then in the 1970s was moved to the Cold War facility at the top of the island. There it was until closure.
The recruit school was supposed to give the soldiers basic skills in military disciplines within 3 months, after which they were distributed to duty stations mainly in Northern Norway. The recruits were housed at the Main Barracks, the Union Barracks (at the Odderøya kindergarten), the Eastern Barracks and the Top Barracks (demolished).
In addition to the aforementioned departments, driving courses and cooking courses were conducted on Odderøya for each contingent. When the recruit school was closed and the Naval District (the few positions that were left) moved to Marvika, the Maritime Guard (SHV area) moved into the Command Place at Odderøya Fort and eventually the SHV section moved into the district's Command Place (Cold War Facility). They stayed here until 2006.
The Shooting School for the Coastal Artillery (SSKA) was from 1953 located on Odderøya. During this time, many family homes were built on Odderøya. The shooting school also required classrooms and an artillery hall. SSKA was responsible for all regulations in use in the Coastal Artillery and conducted courses for professional and conscription officers. The shooting school was located in the building before the kindergarten before they moved down to Quartbrakka. They stayed there until they moved to Bergen. The fact that the Shooting School was located on the island contributed to the fact that the forts on Randøya, Flekkerøya and Odderøya had modern fire control systems that coastal artillery commanders received training on. The shooting school was moved to Bergen in 1997.
In 1999, almost all military activity on Randøya, Krossodden and Odderøya was closed. Many positions disappeared from the peace organisation. The little that was left moved to Marvika where they remained until this department was also closed down.
