About Sveaborg Sea Fortress



The Suomenlinna Sveaborg Sea Fortress, built to protect the entrance to Helsinki harbor, is as close to nirvana as military, fortress and artillery aficionados will ever get.

One of the largest sea fortresses in the world, Sveaborg has enough militaria attractions to keep you entertained for the best part of a day. Here you’ll see several gun batteries, a museum covering the construction of the fortresses, another museum filled with ship models and weapons, another packed with coastal artillery, and a military museum crammed with tanks, artillery, uniforms, weapons and dioramas, and a 1933 submarine that you can walk through.

Sveaborg was a bastion fortress, formed by six enclosed fortresses, on a several islands. Through a wide screen presentation, reader boards, exhibits of uniforms, paintings and other historical artifacts, one can learn that construction of the fortress started in 1748 by the Swedish, who at that time occupied what we now know as Finland.

Until 1808 Sveaborg was the largest fortress in the Swedish realm. Until that date it was the region’s main defense center for protecting Sweden’s interests, also housing a large naval base. After the 1808-09 War between Russia and Sweden, it changed to Russian hands for the next 110 years.

Starting on August 9, 1855 during Crimean War between Great Britain and Russia - the fortress was fired upon continuously for 46 hours by British-French Naval ships that were out of range of the fortress’ guns. The fortress was blasted by kilograms of incoming ammunition, with spectators standing on the shore at Helsinki describing the scene as “ a frightening spectacle of muzzle flames and billowing smoke, flares and numerous fires”.


Continuing through the island’s history, You can see that Finland finally gained her independence in 1918, and the fortress became a Finnish garrison. Today several hundred Finns live on the islands—a kind of maritime suburb—and it’s one of the country’s most visited tourist attractions.


The fortress visitor can find all the elements of a classical European bastion in the island’s four fortresses: sloped fortress glacis, artillery platforms, covered ways and moats, bastions, caponiers, traverse walls and counterguards, and vaulted connection corridors and galleries for short-range defense. Most of the fortresses have at least four parallel defense lines situated one behind the other, usually at different levels, that enabled their guns to be fired simultaneously. And most of these fortifications are interspersed with ditches. Formidable defenses indeed.


On the western edge of Gustavssvard Kustaanmiekka Island,You can find the Russian sand banks and gun batteries; a special coastal defense line built in the latter half of the 19th century. It’s a long sandbank with adjoining gun batteries and ammunition cellars dug into the sand banks. The guns are placed on masonry bases behind the sand bank. Three of these coastal mortars are 11-inch, the eight others 9-inch, set on gliding mounts, placed on an upper and a lower section transverse wedge. The lower section moves sideways on wheels and is fixed to the base by a large pivot. When the gun is fired, the upper section glides back and upwards on the lower one, absorbing the recoil. The redesign of the larger rear diameter of these Russian mortars obviously had this in mind. These were originally German (Krupp) inventions and sold to Scandinavia and Russia. Eventually the Russians adapted and manufactured them under license—in this case N. Maijevskiy designed them—and they were manufactured in the Perm gun works in 1873.


The 9-inch guns had a range of 6.4 kilometers for their 122.8 kg steel shells, and 10Kilometers for the 250 kg shells from the11-inch bore. The rifled gun barrels have several steel mantles within each other. The rate of fire was 1 round every 3 minutes. Technically, these guns are a bit long to call mortars, and they did not elevate enough to drop projectiles downward onto enemy ships, but they were often called mortars to strike fear into the enemy.


On Suisaari Island there is Submarine Vessikko museum. This 250-ton monster was built in 1933 for the German navy, but transferred to the Finnish Navy in 1936. It saw some patrol and convoy action in World War Two from its shipyard base here on the Island. You can walk through the entire submarine and see its well-preserved equipment.


You can spend an entire day clambering over the fortresses, admiring the guns, and strolling through the excellent museums on these islands. There are a number of restaurants spread though the islands.Book a guided tour from Sveaborg Historical Society for a memorable experience.

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