Finnish Coastal Defences Part I
Moving on from the Ilmavoimat, this and the next two or three Posts will focus on the Finnish Coastal Artillery through the 1920's and in to the 1930's. One of the first Posts in this Thread mentioned the purchase of a number of additional naval guns from the French - that purchase and what use is made of the naval guns so acquired as well as some other changes to the Coastal Artillery defences will be covered in the last Post of this series on the Coastal Artillery. In this series of Posts we will also cover the progressive strengthening of the defences over the 1920’s and 1930’s, the defense cooperation with Estonia (with regard to coastal artillery defenses only) and the ongoing problem of the defence of the Åland Archipelago.
Finnish Coastal Defence in the 1920s
In this Post, we will review the origins of the Coastal Artillery defences, and start on the positions themselves together with the artillery allocated.
On independence, Finland had inherited a considerable and effective coastal defence system from Tsarist Russia. This system had been designed and built to block access to the old Russian capital of Saint Petersburg via the sea, a threat which reached back in time to the founding of the city by Peter the Great. Prior to WW1, the most recent manifestation of this threat from the Baltic Sea confronting Russia goes back to the Crimean War in 1854-1855, when a combined British-French fleet entered the Baltic. Although it was too weak to threaten St. Petersburg, it did engage in a series of smaller harassing actions, shelling Sveaborg (Viapori) fortress near Helsinki and the Russian coastal fortresses at Bomarsund on the Aland Islands. In the late 19th century the Russians had already built a series of coastal fortifications along the Finnish coast, stretching from the fortress at Bomarsund on the Aland Islands eastward along the mainland.
The decision to start construction the naval fortress line came after the disastrous events at Tsushima, where the whole of the Russian Baltic Fleet had been annihilated by the Imperial Japanese Navy. The road to Saint Petersburg was left unprotected and open. The quickest and cheapest way of dealing with this problem was to protect Saint Petersburg with a seemingly impenetrable zone of coastal artillery until a new fleet had been constructed. The idea was presented for the first time in 1907. According to the defence plan of that time, the task of the weakned Baltic Fleet was the close-up defence of St. Petersburg from a fortified position. The Kohtlajärvi - Suursaari - Kotka line was chosen as the first such position in the defence plan of 1907-1908. However, this position had several drawbacks. It did not have enough artillery, it was situated in the widest part of the Gulf of Finland (fig. 1), which was hard to defend and it was too close to St. Petersburg. It would also leave the rest of the Gulf of Finland open to the enemy. Because of the drawbacks a suggestion to move the defence line to the narrowest part of the gulf, i.e. the Porkkala - Tallinn (Reval) line, was made for the first time in 1907.
However, it took some further years before anything concrete happened. The plans were studied in several further committees before being endorsed by Tsar Nicholas II in August 1909. However, there was no money available for this plan, and it was not implemented at this time. The defence plans were again referred back to various committees. One of the questions discussed was the numbers and calibres of the guns of the different forts. This plan was called the “Ddefence Plan of 1910”, although the plan was far from completed at that time and the construction of some defenses had begun before that. The Central Defence Line between Reval (Tallinn) and Porkkala was scrutinised again between 1911 and 1912 and finally approved by Tsar Nicholas II on 5th July 1912 with construction beginning soon thereafter. Changes to the plans were made even after that however. While work had first begun under the defence plan of 1910, following the Tsar’s approval of the “final”plan in 1912, this work extended to incorprate an elaborate in-depth naval defensive system focused on the Gulf of Finland. In the following years, work was carried out on an extensive series of naval bases, coast artillery forts and mine barriers on both sides of the Gulf, in southern Finland and along Estonia's northern shores.
The plans for the fortress lines included heavy coastal artillery pieces along the northern and southern shores of the Gulf of Finland, with the emphasis put on the defences of the gulf's narrowest point, between Porkkala (in current day Finland) and Tallinn (in current day Estonia). This was a strategic point, as the two fortresses of Mäkiluoto and Naissaar were only 36 kilometres apart. The coastal artillery had a range of about 25 kilometres and could thus "close" the gap between the shores, trapping enemy ships in an effective crossfire. Furthermore, Tsarist Russia had constructed a major new naval base in Tallinn (Reval) shortly before WW1.
The system consisted of several zones of defence:
1. The innermost zone consisted of the fortresses at Kronstadt, Krasnaya Gorka, Ino and the land and coastal fortresses near Vyborg. The latter were to prevent that the enemy bypassing the Kronstadt line by landing near the Bay of Vyborg.
2. The Rear Defence Line Kohtlajärvi - Suursaari – Kotka was between Kotka and Narva, along the islands that lay between these two points.
3. The Central Defence Line was between Tallinn (Reval) and Porkkala.
4. The Forward Defence Line Hangö – Dagö was between Hiiumaa and the Hanko Peninsula.
5. The Far Forward Defences between Aland and Dagö.
Each line was guarded by a combination of coastal artillery batteries, minefields and mobile surface and submarine units from the Baltic Fleet. The entire system was under command of Admiral Nikolai von Essen, Commander-in - Chief of the Baltic Fleet (Baltiskij Flot) of the Russian Imperial Fleet (Rossiskij Imperatorskij Flot). The mining was extensive. During WW1 approximately 35 000 mines were laid by the Russians in these defensive positions, and 3,500 in the western Baltic. In the Gulf of Finland, most of the sea-mines were laid along the Central Defence Line, Reval - Porkkala. By 1918, a total of 10,000 mines had been laid there. The Rear Defence Line received about 5,000 mines and the Forward Defence Line about 7,000. The minefields were, in turn, protected by mobile forces of the Baltic Fleet. The headquarters and main base were under construction, but as this was not completed during WW1, the bulk of the warships operated from Helsinki.
Admiral Nikolai von Essen, Commander-in-Chief (1909-1915)of the Baltic Fleet of the Imperial Russian Navy. He was widely regarded as the most able of Russian admirals in WWI. Essen urged far-reaching reforms and moderization of the Russian Navy. He recognized early the importance of submarines and aircraft, and sought to promote younger officers based on their knowledge of modern strategy and tactics, also establishing a naval training academy at Kronstadt. Above all, he pushed for operational autonomy of the Baltic Fleet. On 9 August 1914 Essen led part of his fleet towards Gotland to contain the Swedish navy and deliver a note of his own making which would have violated Swedish neutrality and may have brought Sweden into the war. He was ordered back before his plan could be executed. Essen died unexpectedly after a short bout with pneumonia in May 1915.
Russian warships overwintering in Helsinki during the first world war.
At the outset of the war, the far Forward Defence Line was patrolled by four cruisers of the Cruiser Brigade. Behind them, covering the Forward Defence Line and ready to sally forth in support if necessary, was the patrol area of the 60 destroyers, divided into two Flotillas based at Hanko and the Estonian islands. The submarine brigade, operating eight submarines, was divided into two divisions, based at Reval and in the archipelago off Turku respectively. Finally, an offensive naval base was under construction at Libau, but had to be abandoned as it was too expensive. Further, Helsinki and Tallinn were ringed with defensive lines on land, consisting of hundreds of kilometers of railways, bunkers connected with tunnel systems and artillery firing positions. The fortification around Helsinki, Krepost Sveaborg, was centered on the old fortress of Suomenlinna. The construction of the defensive system was slowed down due to the outbreak of WWI.
The General Principles of the Russian Fortifications in Finland
In the early 20th century and during WWI the Russians placed the guns about 20-30m apart in each battery. The gun emplacements were made of concrete and sometimes even reinforced concrete was used. The magazines were made of concrete. Almost all ceilings were covered with iron beams or similar (see later Mäkiluoto). Only in some of the casemates was a rubber-asphalt mix used between the beams and the concrete. If asphalt was not used the roofs usually leaked. Almost no attention was paid to snow, and the entrances to the casemates were normally rather big and were blocked by snow in winter. The casemates were normally drained, but the outlets were often clogged, especially in autumn. There was normally no proper ventilation in the magazines, only small ventholes. Thus the casemates were rather damp almost all the year and no heaters were used. The shells and charges were brought to the guns by hand-operated hoists.
The guns were exposed in open positions. The casemates and magazines provided a low protection from the front, but were too far from the guns and there was no protection from the rear. The command posts were generally strong, low concrete towers. There was no integrated measuring network, but each battery had its own fire command posts. The searchlight shelters were made of concrete. The searchlights were elevated by an electric motor and were often placed on a railroad wagon. Some searchlights had a rock shelter.
An example of a Coastal Artillery Battery
An Example of a Fort - Mäkiluoto
Fort Mäkiluoto (Makilo / MacElliot) was a typical coastal artillery fortress of the early 20th century, although the deployment of the guns differed from the pattern normally used and the fortifications were better made than normally. Mäkiluoto will be used as an example to describe the building of the defences. The reason for choosing this fort is that it was perhaps the most important of the forts of that time. In September 1913 Sergeij von Langskoj was chosen to manage the construction work at Mäkiluoto. He did not get detailed plans of the fort, but had to prepare the final plans after the preliminary work had already begun. The plans were endorsed by various authorities in St. Petersburg where they had been finalised by the summer of 1914. The fort was to have four 8 inch guns in two turrets and six 14 inch guns in three turrets. The 14 inch and 8 inch guns had been ordered from different factories in Russia. None of the guns were on site when work was begun.
The sizes and shapes of the different casemates and bunkers were easy to resolve because there were standard drawings available from earlier projects or the vendors of the guns, power plants and other equipment. The hardest decisions were those concerning the deployment of the batteries and their casemates. Finally it was decided not to place the guns in a "normal" battery, i.e. in a row close to each other (20-30 m apart), but in separate two-gun turrets on different horizontal levels. This enabled a 360 degree azimuth for most of the guns. In addition it was decided to join all casemates and bunkers with covered passages. The searchlights were to be remotely controlled from the fire control station.
One of the hardest problems to solve was how to join the concrete with the bedrock of the island. It was known that a thin layer of concrete would firmly attach to the rock, but not a thick layer of a casemate. In this case the different expansion coefficient of the rock and the concrete would cause problems i.e. cracks in the concrete. To overcome this it was decided to make the outer parts, which were exposed to weather changes, detached from the bedrock. This was achieved by using different layers of concrete and clay on which the outer parts of the casemate could slide in case of expansion. A passage was also made in the wall to encircle the whole casemate. This passage would also help to keep the walls dry. The principles mentioned above could not be applied to all the lower rooms in the casemates. That is why it was decided to apply a 6 inch layer of rubber-like asphalt between the walls and the rock as well as below the floor of these rooms. Unfortunately, there was not enough of this asphalt available because of the war, and as a result water later penetrated some of the walls causing much damage. All ceilings were covered with an "iron-cover", i.e. using I or U-shaped iron beams. On top of the beams was a 6 inch layer of rubber-asphalt. This arrangement prevented concrete fragments falling from the ceilings during an enemy bombardment. To prevent water from condensing inside the casemates they were equipped with a central heating system. This had to be used in the summer to keep the temperature inside the casemates on the level of the outside temperature to prevent the condensation.
Some details of the construction work itself are known. Rather weak concrete was used for the inner parts of the casemate walls. The vaults and the outer parts of the walls were made of strong concrete. Only slow-drying concrete was used. Not very much water was used for the concrete. It was laid 20 cm at a time and manually stamped hard by using groups of men (soldiers) to walk over it at least fourteen times. Mechanical devices could not be used because they would make the lower layers too dry and prevent them from hardening. It was imperative that the concrete factory produced as much concrete as needed to avoid any interruption in the work. When the walls were ready and almost dry the uppermost layer was coverd with cement plaster. When this was dry and the I- and U-shaped beams had been attached and the rubber-asphalt applied, the vaults were filled with concrete as was done with the walls. In order to prevent cracks in the concrete, artificial "cracks", i.e. gaps between thick layers were made. The surfaces of the gaps were plastered with cement and then covered with a thin layer of clay. To prevent water from intruding into these gaps the top of the gap was shaped.
When the revolution broke out in Russia, work was more or less stopped at Mäkiluoto. The fire command post had only been planned. It would have been very interesting as all guns were to be laid and fired from it. The theoretical rate of fire of the 8" guns would have been 10 shots/minute and the 14" guns four shots/minute. In addition to the work completed, an additional casemate for the fort crew, a concrete shelter for armoured cars and a road around the island had been planned. Finally trees and bushes would have been planted to camouflage all the defences. Only about half of the work planned had been completed at this time and even before the work was started, the location of the 14 inch guns was criticised. Mäkiluoto was considered too small for such guns and another larger island was suggested for them, but because the Tsar had approved the plans no changes could be made.
The naval fortresses were only partly finished when both Finland and Estonia declared their independence, following the Russian October revolution. The German Navy performed one major landing operation on the shores of the Gulf of Finland during World War I. In April 1918, following a request from the Vaasa Senate in Finland, the German Ostsee Division, commanded by Rüdiger von der Goltz, landed in Hanko, joined the Finnish Whites in the fight against the Reds and captured Helsinki. The heaviest batteries were supposed to consist of 356 mm/52 m 1913 guns. However, at the time of the Russian revolution of 1917, these were still under construction and were not finished.
The Coastal Fortifications after 1918
Following independence, the coastal defence positions falling within Finland’s borders became a critical component of the defences of the new nation (and many of these positions remain so today, incidentally). The Coastal Artillery became a component branch of the Finnish Military, falling under the aegis of the Merivoimat (Navy). At first Russian fortification principles continued to be used, because most of the Finnish Coastal Artillery officers had been trained in Russia. Positions were in many cases strengthened, new positions were built, artillery was added or relocated and a new defense line was built along the northern shores and islands of Lake Laatoka (Ladoga), with new batteries with two guns being built. The guns were still only 20-30 metres apart. The gun positions and casemates were made of concrete, often of a poor quality. The gun positions were open with no cover at the rear. The magazines were built some tens of metres behind the batteries. The casemates were often not as thick as those built by the Russians. Normally no shell hoists were used. The fire control posts were built as in the Russian time at the ends of the casemates. Normally the coastal defences built in the 1920s had to be partly reconstructed in the 1930s or later.
In the 1930s a new generation of officers were in charge, and their way of thinking was different from that of the old generation. The guns were not emplaced close to each other, but several hundred metres apart. The guns were often modernised to give them a full 360 degree azimuth. Some of the gun positions were installed in the old Russian fortifications, some were rebuilt. Because the guns were improved to give a much longer range than during the Russian times, the old fire control posts were not high enough. A network of new, higher fire command posts was built. In addition, over the 1930’s, defensive ties with Estonia were renewed and strengthened with a considerable emphasis placed on tieing together the Coastal Artillery defences of the two nations, but now with an emphasis on bottling up the Soviet Baltic Fleet in Krondstadt rather than on protecting it.
Thus by the Second World War the former Russian coastal artillery had been extensively modernised. However, the old fortifications were almost all used as such either in their original function or slightly rebuilt. Overall, the Russian-made fortifications proved to be well made. Without the Russian "heritage" a small country like Finland would never have had the necessary resources to develop such a strong coastal defence network. In addition, it also made Finland use "traditional" coastal defence, i.e. based on guns and not missiles, longer than most countries in the world and even today most of the Russian-built coastal defences are still ine use by the Coastal Artillery.
Maps showing the Coastal Artillery Defence positions as of Nov 1917.
The following are a series of Maps showing the Tsarist Russian Coastal Artillery Defence positions located in Estonia and Finland and around St Petersburg as of Nov 1917. It was these positions that formed the basis for the Finnish and Estonian Coastal Defences of 1939.
Map: Russian coastal fortresses in the Gulf of Finland and northern Baltic 1917. Note: At this time Finland and Estonia were still part of Russia. Dots are batteries and arches are approximate firing sectors. (Some battery firing sectors and ranges are unknown, there sectors are drawn based on rough estimates). Range of small caliber cannon and anti-aircraft guns are excluding the map.
Åland Archipelago Positions
Fortresses from Hanko to Helsinki
The Estonian Archipelago Positions
Positions in the Inner Gulf of Finland
The Fortesses of Viipuri and Krondstadt
The Sea Fortresses of Krepost Sveaborg (guarding Helsinki)
The Land Defences of Krepost Sveaborg (guarding Helsinki)
And n the 1920’s, Finland made a major effort to build sea defences along the coast and islands of Lake Laatokka
Krepost Sveaborg - The Land and Sea Fortress of Helsinki During WWI
In this section, we will take a detailed look at Krepost Sveaborg (the Fortress of Sveaborg). The fortress covered the area of present day Helsinki and part of the cities of Espoo and Vantaa. Today the name Sveaborg or Suomenlinna means only six small islands outside Helsinki harbor. The building site of Krepost Sveaborg during WWI was one of the biggest construction sites ever in Finland. The building of the fortifications was supervised by Russian engineering officers. Most of the workers were Finnish wage workers, but there were not enough local workers for the building sites after the war industries started gearing up for war production. More employees from the Finnish countrysidewere coerced into working on the site. Prisoners were also used as lumberjacks and for other manual labor. It is impossible to say with any exactitude the total number of fortification workers in the Helsinki area, but one calculation is that 15,000 workers were used.
The fortification work slowed after the revolution in Russia in March 1917. Finland declared independence 6 December 1917 but work on the mainland front defenses continued until early 1918. After the Civil War broke out in Finland, the Helsinki fortifications were controlled by the Finnish Red Guard. German troops supported the Finnish White Army and landed in Hanko in April 1918. When the German troops attacked towards Helsinki, the Red Guard manned the western land fortifications of the fortress. There was some fighting, but soon German troops together with White Army soldiers captured Helsinki. Most of the Russian forces had left the city earlier (Russia had made separate peace with the Central Powers in March 1918). After the Civil War, the sea front batteries with all other accessories like search lights etc. were transferred to the control of the Finnish Coastal Artillery. While the fortified islands kept their strategic importance, the landward fortifications lost their significance and the landward facing artillery was transferred to the Finnish Army. Some of the landward facing fortifications where sold where possible as scrap. Many parts of the fortress have disappeared under the new suburban areas and roads. Despite that, everywhere in the Helsinki district can still be found trenches, shelters and fire positions.
As we have seen, numerous coastal defense positons were contstructed along the Gulf of Finland. The importance of Helsinki however was it’s use, along with Tallinn (Reval) as a forward naval base. With the growing strength of the German and Swedish Fleets in the Baltic, and the loss of the Imperial Russian Baltic Fleet to the Japanese Navy at Tsushima in 1905, the fortifications of Helsinki (and Tallinn) were a key component in the defensive system for Saint Petersburg (then the capital city of Russia). (The Finnish city of Viipuri was also protected with mainland fortifications).
Fortresses around Helsinki
In the middle 1700's, when Finland was part of Sweden, the fortress of Sveaborg was built on the six small islands outside of Helsinki by the Swedish Army to protect the important naval base. Sveaborg surrendered to the Russians in 1808 and Finland was occupied by Russia in 1809. During the following decades the fortress was developed into a modern naval fortress. The fortress expanded from the main islands of Sveaborg to include several further islands of the Helsinki district. On the outbreak of WWI in 1914 Sveaborg still defended the naval port of Helsinki but the defences were incomplete and there was an urgent need to finish the fortification work that had been started on the islands. There were also some new battery building sites. New concrete batteries were finished rapidly and recieved the proper armaments. The building of field fortifications was started on the hills around the city. The fortification line’s distamnce from the naval port was approximately 7 kilometers but this was found to be too short distance. There was a fear that an enemy army could fire on the harbor in a siege as had happened in Port Arthur ten years earlier in the war with Japan.
The naval port area is located north from the main islands of Sveaborg (below). The main naval base is in the end of the cape (upper left corner). (Russian topographic map from 1911).
At the end of the first year of war, the Gulf of Finland was so strongly fortified and mined that it was improbable that the Germans could have landed near St Petersburg. It was however anticipated that German forces could land from the Gulf of Bothnia on the west coast of Finland. As a result, fortifications were built on the main traffic junctions of southern Finland facing west. The idea was that a defending army could slowly withdraw to south-east Finland while fighting a delaying action and wait for help from Russia. In this kind of situation it would be very important to keep Helsinki in the defenders possession.
The field fortifications in Finland at the end of 1917: Note that these are west-facing – after Independence, these fortification lines all faced in the wrong direction and were of no use as defensive positions against the new threat – Soviet Russia.
As a result of the fears for Helsinki, the land defences were enlarged. The new fortification line was 10 kilometers distant from the main islands of Sveaborg and the harbor. Also a third fortification line on the north and east side of the city was built during the war. The pace of work on the fortifications slowed after the Russian revolution of March 1917, however work continued even after the Finnish declaration of independence on 6th December 1917 and was ongoing evn in early 1918.
Krepost Sveaborg - the sea and land Fortress of Helsinki during WWI. Main roads and railroads are marked. The Naval port is marked by an anchor.
Landward Defensive Lines
Frontlines of different periods. Red lines - old roads, dash lines – railroads
Field Fortification Installations
The first fortifications around Helsinki were temporary field fortifications. Banks were built on the higher hills using sand, stones and soil and small pits were dug into the banks for machine guns. Artillery batteries were temporary field batteries. Therefore there are no battery positions left from that fortification period. Twenty batteries were planned to be built around the city. The strongest guns were planned to be the 229mm (9") artillery type mortars. After the strategic importance of Helsinki was increased the Russians decided to abandon the line on which work was started in 1914. It is unclear how many of the planned batteries were built.
Permanent Fortifications
Atthe beginning of 1915 the Russians decided to build the fortifications further from the city. It was also realized at this time that the fortifications should be stronger and made for permanent use. Wood and stone blocks were the most important building materials before concrete began to be widely used. Towards the end of 1915 there was a decision to build a third defense line on the northern and eastern side of the fortress. Building of that line was started at the beginning of 1916.
A trench is reinforced using stone wall.
A concrete defensive position at Paloheinä
The positions were completed gradually. Plans and methods of constructions continually evolved developed during the war. The philosophy of fortification constructions is that the work never ends and defense lines can be continually strengtheed. During the war, more attention was paid to building stronger firing positions and shelters and the last positions built towards the end of the war were strong systems with several meter thick concrete roofs. When the Russian revolution of 1917 slowed work on the fortress there were only a few unfinished positions. By this time the landward line was divided into three sectors: the eastern, northern and western fronts, with 36 key forts. There were approximately 55 batteries (the exact number cannot be determined) with about 200 artillery pieces.
Sea Island Fortifications
When WWI broke out in August 1914, most of the sea front batteries dated from the end of the 19th century. The sea front started from the island of Melkki and continued through the old Sveaborg (Viapori) to Santahamina. Batteries had been constructed using stones, bricks, soil and sand. The first concrete batteries dated from the beginning of the 20th century. The guns were old, from the 1870's. There were less than a dozen modern 152 mm (6") Canet cannons and 57mm (6 pounder) rapid fire cannon.
The 152 mm (6") 190 puds coastal artillery gun was the most common artillery piece in the fortress of Helsinki. During WWI most of these guns were moved from the sea front to the land front. The picture is from the Sveaborg Fortress Museum on the island of Kustaanmiekka.)
Work on the building of new batteries started a couple of weeks before WWI broke out. New batteries were located on the outer islands of Pyöräsaari, Miessaari, Rysäkari, Katajaluoto, Harmaja, Kuivasaari, Isosaari, Itä-Villinki and the cape of Skatanniemi. The older 19th century batteries belonged to the inner sea front. Some islands also had rapid fire guns and anti-aircraft guns of the 57mm and 75 mm calibre. Older guns were moved to the land front after new guns arrived for the sea front batteries. Most of the Russian troops left the islands in 1918. The Sea Front batteries with all equipment were transferred to the Finnish Coastal Artillery. The fortified islands have retained their strategic importance almost to the present and most of the islands are still military areas. However a few batteries are in public areas - the older batteries on the island of Harakka and in the Sveaborg-Suomenlinna museum area and some newer concrete batteries on Skatanniemi and Pihlajasaari.
Sea Front islands during WWI. The main fairways are marked, as are the Artillery Batteries.
Armament of the Sea Front Batteries -
Outer Line Island Batteries
Pyöräsaari - 2 batteries – 2 x 57/48 Nordenfelt 6 pounder quick fire coast defense gun.
Miessaari – 4 x 152 mm (6") Canet 45 caliber coastal guns. Also land front battery number 115 with 6 x 152 mm (6") 22 caliber guns model 1877 (barrel weight 190 puds) on the Durlacher coastal carriage.
Rysäkari – 4 x 254 mm (10") Durlacher 45 caliber coastal guns.
Katajaluoto – 4 x 254 mm (10") Durlacher 45 caliber coastal guns.
Harmaja - 4 x 152 mm (6") Canet 45 caliber coastal guns.
Kuivasaari - 4 x 254 mm (10") Durlacher 45 caliber coastal guns and 4 x 75 mm anti-aircraft guns
Isosaari – 2 batteries: One of 4 x 254 mm (10") Durlacher 45 caliber coastal guns and one of 4 x 152 mm (6") Canet 45 caliber coastal guns.
Itä-Villinki - 4 x 254 mm (10") Durlacher 45 caliber coastal guns and 4 x 57mm (6 pounder) quick fire Nordenfelt coast defense guns.
Vuosaari, Skatanniemi (unfinished) - 4 x 152 mm (6") Canet 45 caliber coastal guns
Armament of the Sea Front Batteries -
Inner Line Island Batteries
There were changes in the armament of the inner line batteries between 1914-1917. Some batteries were disarmed and the guns moved to the land front.
Melkki (later moved to Itäinen Pihlajasaari) – 4 x 75 mm anti-aircraft guns
Itäinen Pihlajasaari – 4 x 75 mm anti-aircraft guns
Harakka – 4 x 152 mm (6") Durlacher 22 caliber gun, model 1877 (barrel weight 190 puds) and 4 x 57mm (6 pounder) quick fire Nordenfelt coast defense guns.
Länsi-Mustasaari – 4 x 280 mm (11") coastal guns (model 1867 or 1877), 4 x 152 mm (6") Durlacher 22 caliber gun, model 1877 (barrel weight 190 puds) and 4 x 57mm (6 pounder) quick fire Nordenfelt coast defense guns.
Kustaanmiekka – 3 x 280 mm (11") coastal guns (model 1867 or 1877) and 4 x 57mm (6 pounder) quick fire Nordenfelt coast defense guns.
Vallisaari - 4 x 280 mm (11") coastal guns (model 1867 or 1877) and 4 x 57mm (6 pounder) quick fire Nordenfelt coast defense guns.
Kuninkaansaari 4 x 280 mm (11") coastal mortars, model 1877.
Santahamina – 2 Batteries, each of 4 x 152 mm (6") Durlacher 22 caliber gun, model 1877 (barrel weight 190 puds).
Vasikkasaari - 75 mm anti aircraft battery
To be continued in Part II............