HSwMS Svea was the lead ship of the of first-class coastal defence ships (Pansarskeppen) constructed for the Swedish Navy. The ship was armed with two guns provided by the British manufacturer Armstrong. The vessel was launched in 1884 and was subject to a number of armament changes over a service lifespan that lasted until 1915, including, in 1903, replacing the main armament with a single Bofors gun. During the upgrades, the redundant guns often found a role in Swedish coastal defence batteries. Although available during the First World War, the warship saw no action. In 1918, the ship was recommissioned as a submarine tender, serving in this capacity until 1941, after which Svea was decommissioned and broken up.
Svea was the lead of the first-class coastal defence ships, the first vessels of the type to serve in the Swedish Navy. Designed in response to a proposal presented to the Riksdag on 26 June 1880, the new design was approved by the King of Sweden, Oscar II, on 7 December 1883 and a contract for the construction of the new ship signed with Motala Verkstad on 14 January 1884. The design followed the pattern of the Royal Navy ironclad battleship . The boilers, engines, steering gear and torpedo room were all placed under the armoured deck and protected by coal bunkers. The hull was divided into 194 watertight compartments, including 72 in a double hull. The vessel was the first to be built of steel for the navy.
Svea had a waterline length of , a beam of and a standard draught of . Displacement was normal and full load. Power was provided by six cylindrical marine boilers feeding steam to two horizontal marine steam engines. Rated at , they drove two shafts to give a design speed of . During sea trials, on 8 September 1886, Svea achieved a speed of , later increased to from . Two funnels were fitted. A maximum load of of coal could be carried, although normally the full load was . Coal consumption was per horsepower hour at . Range was at . The ship had a complement of 252 officers and ratings.
Armament consisted of two single Armstrong M84 guns mounted in turrets able to rotate 136 degrees to each side and mounted on the ship's centreline, one fore and the other aft. Each of the gun barrels weighed and had a length of 34 calibres. They could fire a shell every five minutes at a muzzle velocity of , giving a maximum range of . Secondary armament initially consisted of four Armstrong guns mounted singularly aft that could fire from a shot every two minutes at a muzzle velocity of . Each secondary gun had a barrel that had a length of 28 calibres and weighed . They had a maximum range of . For protection against torpedo boats, the ship was armed with two M84 and four M77 Nordenfelt guns, with an additional Nordenfelt gun mounted on the top of the unrigged mast. Four extra 25 mm guns were carried to be used by landing parties. A single submerged torpedo tube for six torpedoes was mounted in the bow.
The ship was the first in the Swedish fleet fitted with compound armour. An armoured belt was fitted that was thick at the bow, reducing to amidships and then increasing to at the sternpost. It was mounted on a wooden batten that measured thick, increasing to at the waterline and below it. The main turrets were protected by armour 297 mm thick at the front, on the sides and at the rear. The secondary armament sat behind shields that were 254 mm thick with a cover that was thick. Armour that was thick protected the deck. The armour was manufactured in Le Creusot by Schneider & Co.
Svea, named after the personification of Sweden, was laid down in March 1884 by Lindholmens in Gothenburg and launched on 12 December 1885. The cost of the construction, without armament was SEK 1,134,000. The ship was officially commissioned on 20 September 1886.
On 1 August 1890, the ship led a training mission to visit Härnösand. Later that year, the ship's armament was upgraded with two single Bofors guns mounted alongside two searchlights that were carried on semi-circular platforms on the ship's sides. Two steam sloops were added. Between 1896 and 1897, the secondary armament was replaced by four Bofors guns. Each could fire between five and eight shells a minute at , giving a maximum range of . The 38 mm and 57 mm guns were also replaced by four upgraded 57 mm M/89B guns. The 152 mm guns found a second use, with two being relocated to the coastal defence battery at Karlskrona and one to the gunboat . On 11 August 1898, the upgraded vessel joined a flotilla of ships that also included the coastal defence ships and on a visit to Copenhagen. While there, the flotilla hosted Christian IX, Crown Prince Frederick, Prince George of Greece and other royalty, returning to Karlskrona on 19 August.
In 1899, the Riksdag authorised the modernisation of the Svea class at a cost of SEK 4,920,000. The original concept was to upgrade them to the same armament as the s. The main guns were removed but it was only possible to mount a single Bofors M98 gun rather than two. The new gun fired shells at a muzzle velocity of to a range of at a rate of fire of one shell per minute. A new secondary armament was fitted with seven 152 mm M98 guns mounted singly in turrets, three lining each side and one aft. These weapons could fire shells over at a muzzle velocity of and a rate of fire of 2.7 shells per minute. The new guns were mounted in lighter turrets that offered greater protection as they used compound armour. The main armament was protected by turrets that were thick and the secondary armament with armour thick. Displacement was increased to . The ship's complement was reduced to 232 officers and ratings. Svea was taken out of service on 27 May 1903 to be modernised, returning to active duty after 22 days of work. Once the work was complete, little of the original ship remained apart from the hull and engines.
Between 24 September and 4 October 1912, the ship hosted the British Second Cruiser Squadron, led by the battlecruiser , which was moored at Trälhavet near Vaxholm. At the start of the First World War, the Swedish Navy was mobilised and Svea was assessed for brought back into service. However, the rapid progress in marine technology meant that, on 10 April 1915, it was declared that Svea was no longer fit for an active role. The battleship was removed from service and two of the secondary guns were transferred to a coastal battery.
The decision was made on 15 February 1918 to convert the ship to a submarine tender with the remaining 152 mm guns removed, work that was complete in 1921. Displacement was decreased to . The armament was replaced by four 120 mm M94 guns and two 57 mm M16 anti-aircraft guns. It was decided on 22 April 1932 that the latter be replaced by Vickers guns. The 120 mm guns were subsequently removed, as were two of the boilers and one funnel. The aging ship provided a service as a target for the Swedish submarines. In 1939, the ship was briefly recommissioned as part of the defences against possible invasion in the Second World War. When it became clear that this was not going to happen, on 9 October 1941, the vessel made a last voyage and, on 30 December 1941, was decommissioned. Svea was broken up at Karlskrona between 1943 and 1944.