Finnish coastal defence ship Ilmarinen Ilmarinen was a Finnish Navy " Panssarilaiva " ( " Armored ship " ; a coastal defence ship by British classification ) . The unit was constructed at the Crichton - Vulcan shipyard in Turku , Finland , and named after the mythological hero Ilmarinen from the Finnish national epic , the Kalevala . " Ilmarinen " was the flagship of the Navy from 1 May 1933 until her demise on 13 September 1941 . History . During the early inter - war period the Finnish Navy consisted of some 30 ex - Russian vessels , most of them taken as war - trophies following the civil war . Never ideal types for the navy ' s needs , they were generally old and in poor condition . In 1925 , a tragic incident highlighted the sorry state of the navy . An old torpedo boat was lost in a fierce storm , taking with her the entire crew of 53 . A heated debate started , and intensive lobbying led to the adoption of a new Finnish Navy Act in 1927 . Prior to World War II , the fleet renewal program led to the acquisition or construction of five submarines , four torpedo boats , and two coastal defense ships . Among the last of their kind , the " Väinämöinen " and " Ilmarinen " were two of the most concentrated naval artillery units ever built . They were designed by the Dutch company NV Ingenieurskantoor voor Scheepsbouw , and were optimized for operations in the archipelagos of the Baltic Sea . Their open sea performance was de - emphasized in order to give the vessels their shallow draft and super - compact design . Coastal defence ships were particularly popular in the Nordic countries , and began serving in the navies of Denmark , Sweden and Norway early in the 20th century . These vessels typically had heavy armament and good armor protection , but were relatively slow . Their sizes were around 4 , 000 tons , main armament consisted of guns between 210 and 240mm , the armor corresponded to that of armoured cruiser s , and speeds were between 15 and 18 knots . A coastal defence ship was somewhere between a cruiser and a monitor : slower than a cruiser but better armed , faster than a monitor , but with smaller guns . The coastal defence ships also varied among themselves ; some of them were closer to cruisers , and others , such as the Finnish ones , were closer to monitors . Being the second of her class , " Ilmarinen " was launched at the Turku shipyard on 9 September 1933 . The ship went through its finishing trials and was handed over to the Finnish Navy on 17 April 1934 . Her sister ship " Väinämöinen " had preceded her by two years . The vessels had a compact design , with a high mast and large turrets for main and secondary artillery . Foreign comments on their design ranged from puns to praise . Not truly designed for open sea operations , the ships had a tendency to roll slowly and widely even in moderate seas . Travel on them was unpleasant , but deemed safe . Additional keels were later fitted , which improved the situation somewhat . The " Väinämöinen " and " Ilmarinen " had a displacement of 3 , 900 tonnes , a maximum length of 93 metres , and a draught of 4 . 50 metres . Requirements of speed and range were moderate , as they were expected to operate near their home bases . Both vessels were equipped with four diesel engines that powered two electrical engines . These generated a total of 4 , 800 hp . There were also two smaller 100 hp auxiliary diesel engines . Maximum speed was 14 . 5 knots , and range was further limited by the vessels ' carrying capacity of only 93 tonnes of diesel oil . The four 254mm Bofors guns were massive for vessels of this size , and they could hurl a 225 kg shell up to 31 km . The secondary artillery consisted of eight 105mm dual - purpose Bofors guns in four turrets . These were the primary defense against fast torpedo boats and aircraft . Additionally , the ships were equipped with four 40mm anti - aircraft guns ( initially British - made " pom - pom " guns , which , after mediocre performance in the Winter War , were replaced with Bofors guns ) and two 20mm Madsen auto - cannons ( later increased to eight ) . The purpose of the coastal defence ships was to prevent landing operations and naval blockades that threatened vital sea trade . Thanks to the construction of vast defensive systems during the czarist era , Finland had strong coastal artillery in permanent positions . These defenses were to be supplemented with minefields in times of unrest . One of the main purposes of the navy was to buy time for ground forces to deploy to the islands in the Archipelago . In these confined spaces , coastal defence ships armed with 254mm main artillery would have been a tough opponent for any ship of the era . The Soviet Baltic Fleet was the obvious threat , and the Finnish vessels were meant to deter the largest Soviet ships , such as the battleships " Marat " and " Oktyabrskaya Revolutsiya " , as well as the cruiser " Kirov " , from venturing too close to Finnish shores . Operational history . During her first years " Ilmarinen " made a few journeys to different ports in Finland , once running aground near Vaasa . When the Winter War erupted , " Ilmarinen " and her sister ship " Väinämöinen " were dispatched to the Åland Islands in order to guard against a possible invasion . Due to a decree by the League of Nations , the Ålands were to be demilitarized in peacetime . The Finnish Navy was to transfer resources there when conflict arose . The threat against the Åland Islands receded after thick sheet - ice began covering the Baltic Sea in December 1939 . The two coastal defence ships sailed to Turku where they provided anti - aircraft support for the city . They were painted white to prevent Soviet bomber crews from spotting them , but were targeted by aircraft on several occasions , resulting in one death and several injuries . During the Continuation War the two ships shelled the Soviet base at Hanko Peninsula on five occasions in July – November 1941 . " Ilmarinen " fired twenty shells at the Soviet airfield at Täcktom on 12 July 1941 . The airfield had previously been bombed by German Junkers Ju 88s of " Küstenfliegergruppe " 806 . The two Finnish coastal defence ship participated in Operation Nordwind on September 13 , 1941 , in which German forces were to take the Estonian islands of Saaremaa and Hiiumaa . A group of Finnish and German ships were to be used in a diversionary operation to lure the Soviet fleet into battle – away from the real invasion force coming up from the south . Another German fleet , including the cruisers " Emden " , " Köln " , and " Leipzig " , waited further away to join the battle if the Soviets turned up ; however , the northern fleet remained unnoticed and an order was given to turn around when they had reached a point some 25 nautical miles south of Utö . The formation was led by minesweepers , but some mines had escaped being swept . The crew of " Ilmarinen " failed to take proper notice of the dragging paravane cable . It is likely that the ship had caught one or two sea mines in the paravane , and when the ship turned , the mines struck the bottom of the hull and exploded . The explosion blew a large hole in the ship , which soon developed a strong list and keeled over . It sank in just seven minutes . Only 132 men of the crew survived , and 271 were lost , most of them trapped inside the hull . Fifty - seven were rescued by the patrol boat VMV 1 , which had maneuvered to the capsized hull and took on as many of " Ilmarinen ' s " crew as she could . During this time she too was at great risk of being obliterated if " Ilmarinen ' s " magazines would have ignited . The survivors were later known as " Ilmarisen uimaseura " ( Ilmarinen ' s Swimming Team ) . Amongst them was Lieutenant Viljo Revell , later a renowned architect . The loss of " Ilmarinen " is the greatest single loss of the Finnish Navy to date . The military command tried to keep the loss secret , but Swedish newspapers soon reported the incident , and the numerous sailor obituaries in Finnish newspapers could also have alerted the Soviets , who soon also reported the loss . The ship was located in 1990 . It was found upside - down , deeply embedded in mud , resting at a depth of 70 m . It is classified as a war grave . The wreck of " Estonia " is found some 15 km away .