Naval Fortifications

♖ Naval Fortifications – The art of coastal defence

Harbour defences, sea forts and fortresses, naval batteries and naval sieges in history.

Naval Fortifications is quite a wide topic, spanning centuries and even millenia. When defenders saw a strongpoint on the coast to defend the entrance of a bay or harbor, the reflex was often to create a fort. The sea is the best moat available, perfect in combination with cliffs and solid walls on top.

The first naval forts went back to the antiquity and even the bronze age. The ancient Mycenanean dotted the coast with forts. The Greeks and later Romans built castra (forts) to deal with piracy for example after General Pompeio Magno (Pompey the Great) “cleaned up” the Mediterranean in 60 BC; notably the Adriatic, Aegean sea, and Asia minor, down to the Syrian coast. Many of these strongholds were later converted into medieval forts.

The medieval era is well known for its castles, like those William I of England built to rule his newly conquered island after 1066, but it’s really when the age of gunpowder commenced before the Renaissance, that gunnery started to appear on coastal forts, seen as a way to sink or repel ships better than past catapults, ballistae, mangonels or trebuchets.

The idea was to use these “unsinkable man-o-war” to defend restricted access to harbours and coastal cities, often created in naturally protected bays. A couple of well-placed naval fortifications indeed could interdict an entire area to whole fleets, the gateway to a country, or its trade.

In the XVIIth Century when fortifications became a science (and the art of building them and taking them), naval fortifications multiplied as well, at an age of global empires and fleets in being. When better guns in the XIXth Century (Industrial era) outmatched fortifications, naval forts were refined and never completely lost their potential.

The American Secession war in 1860 started by the assault of Fort Sumter, and the Crimean war was mostly a naval assault on fortifications (Russians), as well as in WWI, the same allies assaulted Turkish Ottoman forts… to be defeated by mines.

In the interwar, fortifications were still relevant and still built or modernized, just as the Maginot line or Eben Emael and many other modern forts were constructed at great cost and ingenuity. At sea, the USN invested much in naval fortifications and perhaps reached the pinnacle of the genre with its “concrete battleships” of the Philippines. Fortifications stayed active even in the age of the atom, during the cold war, but today, they are definitely seen as a relic of a bygone era, after being in service for a thousand years in some places.

Antique fortifications:

Archimedes directing the siege of Syracuse

Before the age of gunpowder, forts were just coastal garrison cities, but could offer some protection against an aggressors with their slings, bow and arrow, and later and ballistae and catapults when they appeared in the Vth Century BC. The Greek and Phoenicians built commercial empires and harbors all around the Mediterranean, placed on the best covered bays, often using narrow entrances. The latter were the best places to built at least an observation tower, to warn the defenders of the city state of an approaching fleet, such as Troy when the unified Greeks arrived on their shores. Famous city-states of the classical era drove their wealth and power from trade, and affirmed their mastery not only by their fleets, but their high walls. Like Athens which created a whole “fortified corridor” between the city and the Piraeus harbor also fortified. It was so feared by the Lacedemonians that peace conditions at the issue of the Pelopponesian wars included their dismantling.

When Alexander the Great tried to conquer the Persians, he tried to eliminate the all-powerful Persian fleet by taking coastal cities by land, one by one. The siege of Tyre (332 BC) showed how far a coastal fortified city of that era could withstand and assault. Later, Rhodes was also besieged and held off all attackers. The diadochi era saw a flurry of siege and fortifications building, with sometimes continuity between a coastal city and harbour, like the long walls running from ancient Athens and the Piraeus, destroyed by treaty at the end of the Peloponnesian wars, won by Sparta backed by Persia. One of these prominent warlord was even called Demetrios “poliorcete”, the “city taker”, and the size and capabilities of siege engineering reached an all-out summit. The Romans would later leanr a great deal about these technologies and improve them.

The “hand-claw” allegedly designed by Syracuse to defeat Roman ships

In between the second and third Punic war, naval fortifications reached perhaps an all-out peak with the fortified harbour of Carthage: The famous round harbour which protected the fleet, virtually impossible to take for any assaulting force. A wonder of construction of the antiquity, it was completely embedded on the city walls itself, the only access by sea was through a narrow passage that could be blocked by a chain, fortifications with archers and ballistae on both sides, and then the civilian port, and the military port inside a circular precinct. During the same era, the siege of Syracuse (214–212 bce) showed how far could be pushed the defense of a besieged coastal city, led by Archimedes himself. Although a part of the Roman tale is dubious at best, we can wonder how Archimedes contraptions were effective. Fact is, they were never repeated anywhere else.

The military port of Carthage in 147 BC.

Medieval Sea fort:

The Roche Goyon Fort in Britanny (1340). Its location made it impregnable and it played an important role during the hundred years war.

Preventing sea invasions involved two types of forts: Primitive “castra” partly in wood close to the coast or back to a cliff corner, in order to reduce the land surface to defend, and river forts, that can defend an inland city. Such forts were built upstream near Paris during the Viking invasions and contributed to repelling these. But another way to defend the land was to have a major fort deep inland and coastal outposts with a string of alarm fires along the way. Once an invasion was detected, the alarm fire was the quickest way to mobilize the army. Well before the Vikings, the Aegean sea “sea peoples” became a nuisance and coastal defences probably erected by civilizations neighbouring the Mediterranean.

The main problem of riverine or coastal forts was with bow and arrows only, it was difficult to interdict a sea invasion of any sort. Ballistae and Catapults were probably required to get the extra reach to do some harm to the approaching ships. The idea of using a chain to block access in a natural bottleneck is another fairly old idea, as well as using a boat barrage across the river. At sea however, there was little ways to block the access of a fleet. The Fort La Latte (1340) was an interesting fort of the late medieval period, in stone and built over granite in a spectacular location, more usable to see the surroundings and defend itself than to prevent a fleet to pass by. Other examples includes the Crusaders’s 1228 Sidon Sea Castle in Lebanon, Mt St. Michel in Normandy, Bodrum castle in Turkey, Mackenzie castle in Scotland and others.

XVII-XIXth Cent. Naval Fortifications:

A Vauban fort: The typical close quarter fortification built from the XVII to the early XIXth centuries.

Around 1327 the first cannons appeared in Western Europe, and in time, they not only revolutionized naval warfare, but also land warfare, and naturally they became the main reason why naval fortification mattered again, and this until WW2. For once, cannons could reach ships at a distance no other medieval weapon was capable of, including a trebuchet. There was a newly-found interest to fortify specific points protecting a bay, an island, a natural passage towards a port or cove. This came in addition to another benefit: Contrary to a ship, a castle cannot sink. Al long as technology allowed forts artillery to stay relevant against ship-borne artillery, this was an even match.

The spectacular Fort Louvois (1690), protecting the Charentes inlet, main way to Bordeaux. It was opposite to the Oleron island citadel for a crossfire, and one of the many first build under Louis XIV. Louvois was replaced by Vauban which dotted the coast with more citadels and sea forts, protecting the entrance to the seine river.

A late 1880s naval fortification: Heavy guns are using an hydraulic recoil system allowing them to be quickly back in position after loading, the latter made just as the barrel ended its recoil course. It allowed to quick fire heavy guns, but the installation was too extensive to be installed in a cramped turret or even barbette, so better suited for naval fortifications. The British had two such guns defending Gibraltar in case of an attack by the Italians, which in 1882 had the largest naval guns ever on a ship, the barbette ironclads Italia and Lepanto.

Naval fortifications played their role at multiple occasions, especially when the Ottoman Navy was head and shoulders in one of the most fantastic and decisive sieges in history: The Fall of Constantinople. Naval fortifications played a huge part in this, especially as the city was basically split in two, controlling access to the black sea. For once, the walls were nearly impregnable, and the Byzantine created a chain barrage at the entry of the golden horn. Further below, on reclaimed Turkish-held shores, the Ottomans built two forts, one on either side, with powerful artillery to impose a blockade. To circumvent the problem of the barrage, ships were hailed outside the walls of Pera, on the Asiatic side, across wooden ways, and to the gold horn, and a boat bridge was bridge further north. After the fall of the city, largely due to the land siege, the Ottomans learned their lessons and fortified not only the golden horn but also the Gelibolu (Gallipoli) peninsula. Old forts were rebuilt and modernized with German Krupp guns before 1914 (see later).

The siege of La Rochelle, in 1627. Painting by Henri Motte in 1881. The protestant stronghold, bolstered by British forces, held the French Catholics led by Cardinal Richelieu (which plays a large part in the funding and organization of the French Navy), lasted for about a year, from 10 september 1627 to 28 october 1628. To prevent supplies by sea, Richelieu started on November, 30 the construction by 4,000 workers of a dike 1,500 meters long and 20 meters high with foundations on sunken, backfilled ships and guns positons pointed towards the sea were to counter any reinforcements. Meanwhile a French fleet led by admiral Marino Torre blocked the harbour entrance. That was basically a repeat of the siege of Alesia by Caesar, but at sea. Indeed, the british soon sent reinforcements, 80 ships under command of George Villiers, 1st Lord of Buckingham, which took the nearby Island of Re, and later a second force by William Feilding, 1st Earl of Denbigh, in April 1628, arriving in May with 60 ships and 6 armored barges. Both failed and the last was sent in August by admiral Robert Bertie, 1st count of Lindsey with 29 warships and et 31 merchant vessels. He battled against the Dike and withdrawn in September. The city capitulated one month later. Richelieu showned a fortfied, gun-armed dike could hold its own against fleet assaults. The lessons were well laerned.

During the The Russo-Swedish War of 1741–1743, naval fortifications also played their part. Vyborg and St Petserburg were not only strategic harbors and arsenals, their approaches were also riddled with Vauban-style fortifications. For the Russians, the waterways in the Gulf of Finland became of strategic importance and small islands constituted unsinkable battleships, trigerring the construction of specialized artillery forts during the XIXth century (see later). The Fort Alexander I, defending the access to St Petersrburg was one of these Kronstadt string of fortifications, quite important at the time, built 1838-45. It was active during the Crimean war, which took place both in the baltic and black sea (sevastopol).

Scandinavian Fortifications

Sweden’s naval fortifications

Fort Frogn Kaholmen, Oscarborg

In 1901 was created the Kustartilleriet, born from traditionsgoing back to the old coastal fortresses in use around Sweden since the 15th century. The command structure subordonated until then to the fortress artillery department. This became an independent branch, starting with the Vaxholm Artillery Corps in 1889. Both coastal defence fortresses and city fortresses were formerly under command of Artillery branch. But with the arrival of the fixed mine defence units the question of an independent branch returned to manage both mines, torpedo and artillery in coastal fortifications, ending with the constitution of the Coastal Artillery in 1902, the fusion of the Vaxholm Artillery Corps, Karlskrona Artillery Corps and fixed mine defence units.

Reforms were numerous but mostly followed a simple rule: Early fortifications were created in the 14th-16th centuries for self-governed provinces and later as Sweden became independent, redundant forst were simply closed and decommissioned. Among these were the oldest, like Bulverket, Visborg and Vyborg Castle, the latter deactivated as embedded in a dense urban landscape. In the tense 17th Century and conflict with Russia, the Kalmar war and 30 years war, New Älvsborg was rebuilt, Carlsten, Dalarö, Gothenburg, Karlsvärd, Kastellet, Nyenschantz, Skansen Kronan and Skansen Lejonet and the Varberg Fortress was ebuilt to new standard of artillery and as star forts. In the 18th Century, Sweden concentrated on new modern fortresses like Suomenlinna and Svartholm.

With the cost of new technologies to assume in the XIXth Century, Fårösund, Karlsborg, Vaberget were built and Vaxholm rebuilt. The last fortifications were erected in the early 20th century: The Boden Fortress, Femöre battery, Järflotta, Kastellet (rebuilt, definding stockholm) the Skåne Line and the Älvsborg Fortress. Reforms were applied to the Swedish Coastal Artillery, and now this patrimony is managed by the Swedish Fortifications Agency. The largest of these was the Skåne Line, erected in WW2 against both Germany and USSR. It was called the “Maginot line of the north” and comprised some 1063 fortifications. The last were discarded in 1990.

Norway’s naval fortifications

40,6 cm Adolph gun at Harstad Battery

With numerous narrows and fjords, Norway was almost impossible to attack by sea and the topography naturally the best place to install fortresses, since 1600, with perhaps the oldest being Akershus Fortress in Oslo. All major ports were towered by their own fortress and artillery battery. With time, artillery positions were installed alongside Fjord entries, well hidden in the landscape. From the XVIth to the XIXth centuries, new constructions were done more specifically to interdict fjords: Fredriksberg, Fredriksholm, Fredriksta, Fredriksværn, Kongsvinger, Basmo, Blaker, Christiansfjeld, Munkholmen, Staverns, Christiansholm, Christiansø, Kristiansten, Altenhus Fortress.

With modern lighting and lectric power a new generation of modern fortifications appeared in the late XIXth century to the 20th century. They will be covered more in detail as contrary to Sweden, these would play an important wartime role with the German invasion: Operation Weserübung:

Hegra Fortress (1908-10):

Built to block Swedish advances into Central Norway: 2x 7.5-cm (3.0 in), 4x 10.5-cm (4.1 in) in pits. Reserve WWI, deactivated 1939.

Helgøya Fortress (1942):

German-built fort to protect coastal traffic and the west entrance to Kristiansand. 4x 10.5-centimetre (4.1 in) coastal artillery.

Kvarven Fort (1895-1902):

Built to defend Bergen harbour and naval installations at Marineholmen and Wallemsviken. The fort was completed in 1899 with four 21 cm St. Chamond cannons and three 24 cm St. Chamond howitzers, three 75 mm QF guns and two machine guns. Later was installed a torpedo battery, fired from above ground. This positions was shelled by the cruisers Königsberg and Köln and assaulted by 1900 troops during Operations Weserübung on April, 9, 1940.

Kvarven Fort, June 11, 2006

Odderøya Fortress (1815):

It was situated on a natural island which creates a division between the eastern and western parts of the port of Kristiansand. This strategic post was attacked by sea, with KMS Karsruhe (which was hit by its defense), the Luftwaffe and 2000 men by land.

Oscarsborg Fortress (1846):

Certainly the most famous. Built in Drøbak Sound, Oslofjord, and thus protecting the entry to Oslo harbor in natural narrows, it was preceded by another fort dating back to 1644, and was rebuilt and modernized the last time from 1890. This “uninkable battleship” had three Krupp 28 cm (11 inch), batteries of 15 cm and QF 57 mm, two underwater barriers and a torpedo battery, dating back from 1890. It was kept “in its juice” until 1940. Unknown the Germans there was also an underground torpedo facility built in 1898–1901. The torpedo battery wasn encased in a concrete construction, inside a natural cave, on the north Kaholmen island. Two torpedoes turbes side by side in open steel frames could be lowered lowered like an elevator, down into the water. The battery has three torpedo tunnels and thus could six torpedoes without reloading, nine torpedoes being stored, made ready for use, with a 100 kg TNT warhead. Targeting was done from three observation bunkers above the battery. The Fort played a vital part in the defense of Oslo at the Battle of Drøbak Sound, by sinking the heavy cruiser Blücher at the head of a convoy. This was the most serious loss of the Kriegsmarine for the whole campaign, except the destroyers savaged by HMS Warspite. This efficient defense, despite being 40 years old equipments, threw back the German naval force heading for Oslo and saved the capital for some time.

Trondenes Fort (1943):

Built by the Germans as part as the “northern atlantic wall”, in the Finnmark, and certainly the most potent close to Harstad. It was equipped by the largest coastal guns at the time, four 40.6 centimetres (16.0 in) Schnelladekanone C/34, also colloquially “adolf guns”, with a range of about 56,000 metres (35 mi).

Meløyvær Fortress (1983):

Basically among the very last naval fortifications in Europe: It defended the entrance of the Andfjorden from a possible Soviet attack. It cosisted in three turreted 120 mm Bofors guns. The whole installation was deactivated and turned into a museum.

Møvik Fortress (1941-44):

Built by the Germans as part of the northern Atlantic wall: This coastal artillery fortress on the Skagerrak was named Batterie Vara (MAB 6./502 Vara), armed by four guns, including a single 38 cm SK C/34 gun (same as a Bismarck class battleship). It was turned into a museum, now called the Kristiansand Cannon Museum.

Spanish Naval Fortifications

Spain in 1210 at the start of the final Reconquista
Spain did not lacked forts and fortresses but had few foes at sea justifying construction of coastal forts, that is until the Muslim arrived at the scene. The Moors succeeded to a fractured country previous ruled by the Visigoths. “Al Andalous” almost covered the entire contry at its greatest extension of the Umayyads in 720 BC. They were contained beyond the Pyrhenees by the powerful Carolingian Empire (battle of Tours) and by a narrow band of territory in the mountains, encompassing the Basque country: The Kindom of Asturias, capital Oviedo. The reconquista took centuries, and in 1200, the now Almohad dynasty only ruled half the country. The north was now divided between several kindoms (see map). The focus of Christian forces was not the sea, but to continue this reconquista until its term under Queen Isabella, with the fall of Algesiras, the last moor stronghold.

Spain, more united until the Crowns of Castille and Aragon (not forgetting nearby independent Portugal which started to capitalize on the sea), started to built a trade and military Empire, using notably a flurry of new warship innovations in contructions and soon exploiting the recent discovery of the Americas, an enterprise originally funded by Isabella and Ferdinand and led by Cristobal Colon. From there, development of naval fortifications commenced in the south to defend the coastline against further muslim invasions, with Cartagena as the linchpin of local defence.

Later as trade and more expeditions transformed south america into the “new world”, local first were built to secure conquistadores and colonists against indigeneous hostility. In the 17th century in particular, the danger of piracy became such as issue that many colonial outposts between the Carribean and south Americas were properly fortified.
This will be the object of a separated section on the “new world sea forts”. Let’s see a few examples:

Castle San Felipe de Barajas

The impressive Cartagena Fortress, created to defend the new strongpoint of the Armada in the new world, in Colombia. The Castillo San Felipe de Barajas is a fortress protecting Cartagena, Colombia, built in 1536 on the Hill of San Lázaro, a strategic location dominating all approaches to the city, by land or sea. The fortress took part in many battles in late 17th to early 19th centuries. The fortification comprised several walls, wider at the base, narrow toward the parapet which protected one another. It had a spectacular grand entrance and complex maze of tunnels. In fact, it was the most formidable defensive complex of Spanish military architecture, towing 41 meters (135 ft.) above sea level. There were more than a hundred heavy bronze guns served by a permanent garrison of circa 4000 men. Even if besieged, rainwater was collected and there was a secret passage for supplies.
To the triangular Castillo de San Felipe, were added batteries Santa Barbara, San Carlos y Los Apostles, Hornabeque, Cruz, Redencion, and San Lazaro which combined 68 additional guns.

San Luis de Bocachica Castillo

Castle of San Luis de Bocachica, definding the approaches of Cartagena, Colombia, built in the 17th century as a star fort. Also known as the Fort of San Luis de Bocachica, is another colonial fortification, located on the island of Tierrabomba, and defending the approaches of Cartagena de Indias in Colombia.
Built between 1753 and 1770 to protect the entrance to the Bay of Cartagena from British and French pirates and privateers it was named after King Louis IX of France (San Luis) and had thick walls, a drawbridge, a moat, and a series of ramparts and towers. It was armed with a battery of cannons and mortars, and was designed to withstand prolonged sieges.
The castle played an important role in the defense of Cartagena during the various wars of independence in the early 19th century. In 1815, it was captured by the forces of Simon Bolivar, who used it as a base to launch his final assault on the city.

Fortín San Juan de la Cruz

Fortín San Juan de la Cruz, also known as El Cañuelo, is a historic fort located on the eastern tip of the island of Vieques, Puerto Rico. It was built in the 19th century by the Spanish government to protect the island from invasions. The fort is named after Saint John of the Cross, a Spanish mystic and Carmelite friar who lived in the 16th century. It was constructed using local materials, including coral blocks, and its design includes a central courtyard and several defensive structures, including a watchtower and a gunpowder magazine.
During the Spanish-American War in 1898, the fort was briefly occupied by American forces, and it remained under their control until the end of World War II. Today, the fort is part of the Vieques National Wildlife Refuge and is open to the public as a tourist attraction.

Peñón de Vélez de la Gomera

Peñón de Vélez de la Gomera is a small rocky islet located off the northern coast of Morocco, but it is a Spanish territory. It is known for its historical significance as a military fortress and strategic point for control of the western Mediterranean Sea. The rock, which rises to a height of 27 meters above sea level, is located about 120 km east of the Spanish city of Melilla and about 95 km west of the Moroccan city of Al Hoceima. It is uninhabited except for a small garrison of Spanish military personnel.
The Spanish first established a fort on the rock in the 16th century to protect their commercial interests in the region. The fort was later rebuilt and expanded in the 18th century and again in the 20th century, and it has been maintained as a Spanish military outpost ever since.
In recent years, the rock has been the subject of territorial disputes between Spain and Morocco. Despite the challenges, the Spanish have maintained their presence on the rock, and it remains an important symbol of Spain’s historical and strategic ties to the region.

Peñón de Alhucemas

Peñón de Alhucemas is a small rocky island located off the northern coast of Morocco, but it is a Spanish territory. It is part of a group of islands known as the Alhucemas Islands, which also includes the larger islands of Isla de Alhucemas and Isla de Tierra.
The rock is located about 300 meters off the coast of Morocco and is about 220 meters long and 84 meters wide. It is uninhabited except for a small garrison of Spanish military personnel.
The Spanish first established a presence on the island in the 16th century to protect their commercial interests in the region. The current fort was built in the 18th century and has been maintained as a Spanish military outpost ever since. Like Peñón de Vélez de la Gomera, Peñón de Alhucemas has been the subject of territorial disputes between Spain and Morocco. However, the two countries eventually reached an agreement in 2002 that recognized Spain’s sovereignty over the island while granting Morocco fishing rights in the surrounding waters.
Today, Peñón de Alhucemas remains an important symbol of Spain’s historical and strategic ties to the region, and it is still used as a military outpost by the Spanish armed forces.

Chilean Fortifications

In Colonial times the Spanish Empire diverted significant resources to fortify the Chilean coast, after being rampaged by Dutch and English privateers. The alarm was sounded after the Dutch occupation of Valdivia in 1643. Spanish authorities ordered the construction of the Valdivian Fort System from 1645. During and after the Seven Years’ War, the Valdivian Fort System was updated and from 1764 considerably reinforced, including Chiloé Archipelago, Concepción, Juan Fernández Islands and Valparaíso, this time to face English raids. The former governor Santa María drawn and advises to built a standardized “city-fort” based on Ancud in 1768 placed later under the Viceroyalty of Peru.

Portuguese Fortifications

(To come next)

Russian/Soviet Fortifications

Shlisselburg Fortress, one of a series of fortifications built on Orekhovy Island, Lake Ladoga, well before St. Petersburg was founded by Peter the Great. The first fortress was built in 1323, the scene of many conflicts between Russia and Sweden, changing hands many times.

The history of Russian naval forts and fortresses is linked to the development of the Russian Navy under the impulsion of Peter the Great in the XVIIth Century for the Baltic, an initiative pushed forward in the black sea by Queen Catherine the Great in the next century and compounded all along the XIX century. They played a great role in the Crimean war, but also the Russo-Turkish wars, the Russo-Japanese war, making Port Arthur seemingly impregnable, or also the civil war between the red army and the Russian “whites” supported by Western powers. They even played a role in WW2, notably with the long attrition war at Sevastopol, fixing substantial axis forces for more than a year.

Although the story of medieval and renaissance Russia, wether concerning the principate of Kiev and Moskow, great rivers were also part of the way the country was shaped. The “Rus” Vikings which came from the sea settled there. Their later successors also travelled by rivers down south, and reach Byzantium, becoming the famed Varangian Guard and the trade between the Mediterranean and Baltic spawned dozens of cities along the Dniepr and further Est, the Don, country of the Cossaks. Many large fortresses were built there, including main Cossaks strongholds called “Siech”. They played their part in the XVI-XVIIIth Century. Moskow itself was smack-bang between the Volga and the Oka, used also as mean of fast transportation and trade lanes and controlled by many forts.

Sviyazhsk, built in 1525 to control the Tatarstan

Boyars built small fortresses on some topographical features giving them some advantages. In particular, Sviyazhsk, located in the confluence of three rivers, the Volga, the Sviyaga and the Schuka. In 1586 for example, was constructed the “Samara township” fortress on the Volga. Large Cities like Kazan and Nizhni Novgorod were themslves originally strong fortresses along the Volga, but Saratov (1590) was specifically designed to control trade; the large and fearsome Porkhov Fortress had a whole trading city developing around. As for the middle Volga, a whole serie of Cossack fortresses were erected in the 18th century, armed with cannons to control the river, something older forts can’t do. The famed Ivan the Terrible Sviyazhsk castle proved instrumental in securing Moscow’s victory over the Golden Horde, but so was Wozdwizhenskaya Fortress.

Peter the Great’s Naval Fortress

Fast forward and the founder of the Russian Navy, Peter the Great, started with a fortress, but not a Russian one. Instead, Swedish colonists built Nyenskans at the mouth of the Neva River in 1611. Later called Ingermanland it was also inhabited by Finnic tribe of Ingrians and the town of Nyen grew up around it. On 12 May 1703 (Great Northern War), Peter the Great captured Nyenskans and considerably improved and enlarged the fortress.

On 27 May 1703, closer to the estuary on Zayachy (Hare) Island, he create the massive Peter and Paul Fortress, the first brick and stone building of the new city, which was drawn using a rectangular grid of canals, based on later renaissance plans. In fact the whole city developed around Trinity Square on the right bank of the Neva, near the Peter and Paul Fortress. Later a military port and yards were added, and so new forts were installed to protect the approaches of the new city.

Peter and Paul was obsolete and in XIXth cent. used as prison and attacked during the Revolution of 1917. Taken by the Bolsheviks and after the signal blank salvo of Aurora at 21.00, her guns fired 30 shells at the Winter Palace and later returned to her role as prison. In 1924 she was mostly converted to a museum.

Kronstadt Fortress

Demidov Battery Today

On 5 April 1784, Admiral Greig signed a plan for the Admiralty in Kronstadt and under Catherine II, transferred it from Saint Petersburg due to the development of the city manwhile. Kronstadt was an island and it was planned, in addition to a fortress, to raise there an office and residential buildings, warehouses and hospitals. The harbor was also dredged. It was catastrophically flooded, fortifications destroyed, cannons washed away in 1824. But she was rebuilt on a new, more modern plan under engineer–lieutenant colonel Lvov.

It took the shape of an irregular quadrangle, protected on the Kotlin Island side by a wall with towers and escarpment. The rest also had an escarpment wall partially replaced by walls of the 1st Western defensive barracks and half–tower rebuilt in 1903–1906, plus the 2nd Western defensive barracks built 1826–1829 also in 1906. The Kronverksky canal was dug and northern city defenses were formed by four Defensive Barracks built from 1831 to 1871, some with semi–towers. There was also the east fifth Eastern Defense Barracks. Breakwaters with platforms for cannons on the sea side were completed by the Knyaz Menshikov battery, protecting the entrance to Srednaya and Kupecheskaya harbors. In 1856, a largely Britsh fleet shelled Kronstadt but was forced to retire, as part of the Crimean war.

In 1904-1905, Kronstadt joined the general uprising after the Russo-Japanese war. The fortress was still troublesome in 1915 but Russians sailors were still patriots and held their position. The fortress was not worried by developing events, the German fleet being busy securing the gulf or Riga; So close to St Persburg, the revolution in Kronstadt in February 1917 was rapid and violent. It was soon claimed by the Bolsheviks and also fought in 1919 against a Royal Navy incursion in support to the white Russians. It was put in the front line of the civil war by Yudenich’s White North-Western Army in May 1919. During the interwar, modernization was limited to the addition of more modern guns, and some AA batteries. But the original fortifications were ill-prepared to sustain modern heavuy artillery or bombs above 500 kgs.

Kronstadt under attack by the Luftwaffe, 1st June 1942

In the late 1930s, the city was the base of the Soviet Baltic Fleet, an important training centre while its dockyard overhauled and repaired surface ships and submarines. Forts and batteries were reconstructed with modern reinforced concrete and the process was still ongoing in 1941. At 23:37 on June 21, 1941, Baltic Fleet Commander Vice Admiral V. Tributs, on order of the People’s Commissar of the Navy Admiral N.G. Kuznetsov mobilized the fortress, hours before the Luftwaffe started to dropp mines into the canal. First lieutenant S. Kushnerev commanded the anti-aircraft batteries and shot down three and damaged several other on 27. The 1st Air regiment of the southern forts would have to repel more raids by the Luftwaffe in August 1941. Stuka ace Hans-Ulrich Rudel took part in it and famously sank the battleship Marat anchored nearby.

To prevent landings, 13 artillery batteries were established and nine more outside the city on Kotlin Island, manned by two infantry regiments. Tallinn was evacuated later and a submarine subdivision organized in Kronstadt, leading 82 naval operations and the Germans tries to block them with anti-submarine nets and mines. by In 1942, the Kronstadt sub fleet sank 29 German vessels and they cooperated with reconnaissance aircraft. Later for the protection of Leningrad, 10 brigades of naval infantry, four regiments, and 40 separate battalions and companies were formed in Kronstadt. The fortress continued to be pounded by field artillery and the Luftwaffe, especially by September 1941 when the dockyard wa ravaged, whereas workers were still on duty 18–20 hours a day. Kronstadt avoided the the destruction of Leningrad, and obtained postwar the title of “City of Military Glory” by Dmitriy Medvedev on April 27, 2009.

Sevastopol Fortress

The 1854-55 siege of Sevastopol

Since the humiliation of the Crimean War, Russia had extended the defences of Sevastopol, the main arsenal and base of the Black sea fleet established by Catherine the Great. It was founded already on February 10, 1784. An admiralty and a military settlement were erected first on the deserted shores of the Akhtiarskaya Bay. In 1830, two forts were built, bristling with guns, and completed in 1854. Approaches were defended by two “stone battleships”, the Konstantinovsky and Mikhailovsky forts, erected in 1840 and 1846. Located on both sides of the entrance to the Sevastopol Bay, protecting it from approaching enemy ships.

The Siege of Sevastopol (1854–55) carried out by the British, French, Piedmontese, and Turkish troops during the Crimean War lasted for 11 months and saw pre-ironclad vessels duelling with forts, a distant prologue to the Dardanelles. Decision however was obtained when main forts were taken, and after Malakoff fell, the Russian retired. The following humiliating peace treaty led to severe measures to enhance the defences of the whole area.

In WWI Sevastopol played little role during WWI, apart for the 29 October 1914 back sea raid when the ex-Goeben and Breslau (Yavuz and Midilli) came to bombard the coast. Yavuz shelled the port for 15 minutes, exchanging fire with the pre-dreadnought Georgii Pobedonosets and shore batteries before retiring.

The Black sea in 1905 and Odessa already had been the scene of a famous revolution and the Potemkine mutiny, and naturally was not long to take arms after the 15 March 1917 abdication. It did not fell in the hands of the Bolsheviks however and on contrary, sailors committees were formed on the ships of the Black Sea Fleet commanded by Vice Admiral Alexander Kolchak, later failing to maintan discipline, was recalled by the Kerensky’s provisional government. The city became a “red” stronghold in November-December 1917, the start of the “red terror” with all officers on sight rounded up and shot on 28 December 1917 on Sevastopol’s Malakhov Hill. It was followed by the civil war and fierce fighting with monarchist Whites, lasting until November 1920.

In the interwar, the Soviet naval base was beefed up for more than 15 years and became perhaps the strongest naval fortification in the world. The site presented already a deeply eroded, bare limestone promontory which formed a naturally ideally placed to built fortifications at the southwestern tip of the Crimea. Approach by land forces was very difficult, far more than Port Arthur. High cliffs overlooked Severnaya Bay and protected the anchorage. The Navy modernized the port and placed heavy coastal batteries armed with 12-in and 7-in (180mm) re-purposed battleship and cruiser guns. With their fully revolving turrets they could fire inland as well. Emplacements were protected by a ring of reinforced concrete fortifications for their approaches, plus 9.8-inch thick armored turrets.

A ravaged Sevastopol in 1942

The axis attack started in October 1941 and the battle would rage until 4 July 1942. The fortress was manned by the “Separate Coastal Army” under Ivan Yefimovich Petrov, already reinforced by evacuees from the the siege of Odessa while the The Black Sea Fleet sent 49,372 personnel to fight as infantry. The defence of the city was really a Navy affair through and through, and the blmack sea fleet (One battleship, two heavy cruisers and a Light Cruiser, two Flotilla Leaders and six Destroyers, nine Minesweepers and a Guardship plus 24 Submarines) played little role but AA defense, being sunk with few exceptions by the Luftwaffe. This became one of the largest battle of attrition of WW2, with more than 320,000 losses on the Soviet side, most wounded, and 36,000 on the axis side, including 8,400 Romanians. Even the regia Marine played a role in it, trrying to intercept reinforcements from the Kola Peninsula (which was also attacked).

The attack proper on the fortifications was the fiercest from 16 June 1942, the Wehrmacht committed its largest artillery pieces of the war, between giant mortars and the massive 800 mm “Schwerer Gustav” (Dora) special railway gun, concrete-busting special bombs, sappers and special remotelly operated demolition vehicles like the Goliath. In this grinding match, Forts Maxim Gorky, Molotov, Schishkova, Volga and Siberia were eventually overrun. The fall was completed on 30 June-4 July by the Wehrmacht taking forts Oktyabrsky and Petrov. On this last leg, for the June 1942 alone, German field artillery claimed to have spent 67,278 tons of ammunition. The defence os sevastopol gained after WW2 an aura of desperate heroism that still echoes today especially in the Russian-Ukrainian context today.

Vladivostok Fortress

Vladivostock fortress main turret,

Long dubbed the “most powerful sea fortress of all times”, was a the complex of long-term defensive works constructed at the end of XIXth century, expanded and modernized at the the beginning of the XX century. Its construction was 2/3 completed when WWI broke out, and long stopped due to the October revolution. This was indeed a gigantic asset, a complex network over 400 square kilometer territory, with some 130 fortifications, strongholds and shore batteries. In the interwarn, they boasted 1,400 heavy guns alone, absorbing a significant portion of what Obukhoff and other manufacturers was able to produce.

In WWI they never fired a shrt, but for sure deterred any approach from the sea. In 1923, the fortress was sidelined under the terms of the agreement with Japan and permanently abandoned. By the early 1930s however under the impulsion of Stalin the formation of the Marine forces of the Far East had the fortress considered an important linchpin of Soviet defense on the area and the Pacific fleet as a whole. Import efforts were made to rapidly modernize and improve the quarters and installations. Quality and durability of constructions and modernization made it still relevant in WW2.

The Japanese government in fact was deter to not enter war against the Soviet Union outright. In 1934, the Voroshilov battery was built on Russky island after two years of construction. It was largely underground, with state of the art reinforced concrete domes and buried turrets. Two towers were supported by an underground support base under 15 meters. The concrete vault was 3.5 meters thick, bomb proof for almost a ton. The towers were connected also by an underground passage of 200 meters. The massive 12-inches naval guns (305 mm) weighted 51 tons apiece, but traverse was manual; No power generator or steam engine was installed. The battery fired its first shot in 1939. It should be noted that, being over 63 years on action station, the battery fired only practice shots.

In 1941, the fortress boasted on the land front 1290 guns, 268 machine guns, 572 ranged weapons, 64 mortars and 36 rocket launcher, and for the coastal front 316 guns, 56 machine guns and 36 rocket launchers. Until 1997, the Voroshilov battery was still listed as active, now part of a museum, the Voroshilovskaya Batareya Museum which exposes a full triple turret, and the three other salvaged barrels. The other turret was removed and recycled.

Port Arthur

After seeing Kronstadt (Baltic), Sevastopol (Black sea), and Vladivostock (Pacific), the defensive assets of each Russian Imperial Fleet was covered. Or so it was ? Due to the peculiarities of epilogue of the 1st Sino-Japanese war in 1895, Russia seems to reap the fruit of Victory from Japan, obtaining concessions and eventually four years later, signed a 25-year lease on the Liaodong Peninsula. There was a natural anchorage there, on which a new naval base, ideally placed to control Korea and the sea of Japan, was placed. Thus place, with the old fortified city of Lushun, became the naval station named “Port Arthur” (Оборона Порт-Артура, Oborona Port-Artura), turned into the southern dependency of the Pacific Fleet.

Needless to say, it contained, in addition to the 1902 alliance of Japan with Great Britain to counterbalance the growing weight of Russia in the far east, the germs of war. Between 1898 and 1904, so just six years, not a lot in terms opf fortification contruction helped by the first railways lines established to this region, Port Arthur was beeffed up in a matter of a few years with fortifications of a level never seen in Asia, using the latest technologies of reinforced concrete and pillbox, blockhaus bristling with guns of all caliber, 506 in all.

On the other hand, the city was basically a garrison of around 87,000 souls, whereas in 1904, the Russians amassed there 50,000 professional troops, 44,000 volunteers mostly from the nearby city, 12,000 sailors from the Pacific fleet, and 7,000 recruits, mostly Korean and Chinese auxiliaries. The latter made the largest construction effort and to make progresses, troops were commited to the works.

Russian Battery in open air

Ishunkou Fortifications

Tiger’s tail promontory main fort

The main Port arthur Fortress. Most of the gun emplacements are in open air. No turrets were present.
Large batteries turned towards the sea were installed first to protect the approach by sea. However these heavy guns, mostly or 10 inches and 8 inches caliber, were still not covered by casemates. They were in open air at the time of the Japanese attack, unfinished. However the major weakness was access by land behind. Russian improvements therefore included a multi-perimeter layout, with overlapping fields of fire to protect the approaches erected in hill ridges, making the best possible use of the natural terrain.

Many of the redoubts and fortifications were still unfinished in 1904 whereas efforts has been made to improve the fortifications at Dalny further north, for little gain as history shows. Nevertheless some of these hills of the inner perimeter were the best prepared, with a few heavy caliver guns on top, mostly 6 and 4 inches plus mortars, and entire concrete walls along the ridges dotted with embrasures all along bristling with Maxim machine guns. In all perhaps 2,000 of them had been deployed on these approaches.

The main fortress, backing the harbour was buried with a large ditch in front of it, called the “Keekwanshan break”, and the whole facade was dotted with machine gun emplacements. In fact, 1.5 kilometers (0.93 miles) behind this hills defensive lines, the original stone Chinese wall encircling Lushun from the south, to the Lun-ho River (northwest). The Chinese wall was extended to the west and south to completely enclose the approaches to the harbor and New Town of Port Arthur. It was all dotted with with concrete forts with many machine gun emplacements and connecting trenches.

The natural approaches of the hills were barren, featurlesss and devoid of any tree, enhanced by barb wire, for the first time used in a massive way. Mines, whenever possible, were also used. Without any protection, attackers would have to simply charge the Russian defences, which had a perfect arc of fire. For the first time, the Russians turned modified naval mines into land weapons. To avoid surprises by night, electric fences were combined with arc lamp and searchlights. To bolster the land defence at some point, Major-General Baron Anatoly Stoessel decided to strip the damaged Russian vessels in the port of their guns during the siege.

However they underestimated the Japanese response: In addition to Admiral Togo’s night attack of Port Arthur which started the war on 25 July 1894, the Japanese Third Army, about 150,000 strong, backed by 474 artillery guns under the command of General Baron Nogi Maresuke soon landed and started its advance to besiege port arthur by land, on August, 1st. It proceeded first with the Battle of the Orphan Hills from August, 7, to the Battle of 174 Meter Hill on the 13th, and the siege itself, with the Battle of 203 Meter Hill which proved decisive for the Japanese as they could bring on top of the hills their heavy 28 cm mortars, overlooking the port. From there, they destroyed the remnants of the Pacific fleet, which failed to pierce the blocklade and join the rest of the fleet in Vladisvostock. Then, they proceeded to bombard the new city and port installations into submission. Soon after the remainder of Russian forces surrendered. See the Russo-Japanese war in detail and battle of Tsushima for more.

Lessons of the conflict, in many ways determined what a modern fortification could achieve, but also how much modern artillery could be deadly. For the first time also, the conflict saw tactical radio signalling and, in response, radio jamming. Grenades were used very liberally in assaults, and would the siege last a bit longer, the Japanese worked on an early flamethrower and even a portative machine gun. In comparaison the war in the Balkans and the Italo-Turkish only saw more primitive defenses involved, but the concepts elaborated at Port Arthur were well studied by the French Military engineers given reports as per the Franco-Russian alliance, and lessons were passed onto the design of Verdun’s ring of fortifications back in France…

All in all, the assault indeed cost the Japanese far more they had anticipated: They lost 57,780 casualties plus 33,769 sick over a total of 150,000 engaged, thrice the number of Russian defender, according to the old and well-known rule about the prortion of troops needed to overcome a well entrenched enemy. Losses were such that chief commander, Baron Nogi Maresuke wept when explaining his losses at the Emperor, and when the latter passed out, committed seppuku the very day of his funerals, as he was denied to do so as long as the Mikado was alive. Nevertheless it was a painful souvenir for the Chinese too, as the whole population was massacred. A stark anticipation of atrocities to come in the second Sino-Japanese war, 32 years afterwards. The place is now the port and arsenal of Dalian, well known by US analysts. Read more and this.

Naval Forts in the Americas

(In writing)

⚠ Note: This post is in continuous expansion, with more sections planned in 2023-24 and beyond. Stay tuned !

Italian Naval Fortificationss

Modern harbour defence

Typical harbour the the early XXth century. Yards, cranes, warfs, rail, were all interconnected, large hangars were used for smaller ships construction, large storehouses for provisional bulk storage, large fuel tanks, oil tanks, captain’s shack and administrative buildings, were all part of the landscape, but no fortifications. Since these vulnerable installations were located inside a cove or bay, the field of fire would have been less than optimal, and if the ship reached that point, that was over already.

But this was only due to the development of long range artillery during the late industrial era. At the start of the XIXth Century, cannonballs and smoothbore muzzle-loaded cannons were the norm and both accuracy and range were limited to 5 kilometres at best. This made harbour fortifications useful, and most of the old coastal cities of Europe were both walls, and fortified on the seaside as well. Ships went into anchorage literally “under the guns” of the harbour in that case. In the Caribbean, at the height of the piracy in the XVIth Century, pirate fleets went duelling with such fortifications, or pound the city itself.

Most of colonial outpost, when grown enough, gained such fortress battery towering over the harbor, this was pretty current in the Carribean, and the Empire-builders of the XVI-XVIIIth Centiry dotted their new possession with these and a good measure of deterrence, even though artillery progress made a 3 battery strong warship plenty of arguments -starting the number of guns- to silence them.

Fortified Lighthouses

The lighthouse is another specific site narrowly linked, and strategic to coastal operations. We will not go back to the “pharos” of alexandria, perhaps the most illustrious of all, but concentrate here of strategic and tactical considerations about the use of lighthouses. There are currently 21,600 lighthouse today, most still in use, but a large part are being decommissioned and/or converted for touristic purposes. Originally these structures had a specific functions, of marking dangerous coastlines, alerting on nearby hazardous shoals and reefs or rocks, as well as providing a safe entries to harbors in heavy weather and poor visbility. Today they even play a role in modern digital and satellite guided navigation, by ptoviding beacons and assisting in aerial navigation, like auxiliary ACTs.

The Punta San Raineri fortified lighthouse, controlling the strait of Messina (Charles Quint)

The idea of blasting out a lighthouse, or just capturing it in wartime was seen as a way to cripple enemy navigation and could enter in the set of blockade strategy in any Navy. There were thousands of “fortfied” lighthouses, but the immense majority were just part of an existing fortification, rather than a self-contained fortfied site. Placed on strategic rocks, often controlling bays or entrances, they were also a tempting site to place artillery. In some cases, they were just the tipping top of an artillery tower, although the blast of artillery could be sufficient to topple over or break the fragile mirror components used.

The Torre del Oro in Seville (painting by David Roberts)

The Torre de Belem, a landmark of Portugal.

Closer to the XIXth Century, the fortified lighthouse of Wisłoujście Fortress was a regular tower with a permanent fire on top. In Northern France also, Dunkirk, Gravelines and Calais lighthouses were all fortified in the Vauban-style fortess.

Here a late XXth century Lighthouse

In more modern times, and both world wars, lighthouse were soon found in strategic place surrounded by batteries to prevent their capture. The “fortfication” were merely posterior additions of blockhaus and trenches, with barb wire, light projectors, machine guns nests and artillery batteries. Their only goal was to prevent an enemy landing.

During WW2 the the White Cliffs of Dover covered themselves with naval guns batteries, AA batteries, acoustic detectors, and anti-aicraft projectors. One site in particular, the South Foreland lighthouse complex, was found itself at the forefront of this “Channel war”. It should be nother that the Geneva Convention stopped lighthouses being used for military means. The grounds of South Foreland as a result became an island surrounded by batteries, its light turned off to prevent German shipping direction the tower itself being camouflaged. It was known by the Germans however, well reported in maps, and therefore fired upon at several occasions. Heavy batteries on both sides of the Channel were not only able to criplle any ship passing by, but also to fire almost on the other shore. This particular battery also fired on the escaping German battleships during the ‘The channel dash’ in 1942, with little success due to poor weather. In all the white cliff batteries in the Channel sank or seriously damaged 29 enemy vessels during WW2.

The Hanko Lighthouse, surrounded by fortifications was a focal point in the baltic, between the Finns and Soviets, for the control of the Gulf of Finland during WW2.

Famous Naval Fortifications of WW1

A Typical fortified bunker and associated AA. This was a widespread type or naval fortifications, especially in Scandinavia.


(In writing)

The Dardanelles Forts

(In writing)

Famous Naval Fortifications of WW2

Singapore, the Gibraltar of the Pacific

The Philippine’s “concrete Battleship”

The famous “concrete battleship”, Fort drum (diagram), built on the island of El Fraile, already used as a base of artillery by the Spaniards in 1898.

Located south of Corregidor, between the peninsulae of Cavite (south) and Corregidor (north), which protected the outskirts of Manila Bay, was one of three concrete forts by the Americans in the 1910-1917 years, with Fort Hugues (Caballo) to the north and Fort Frank (Carabao) to the south, equipped with firing positions and firing direction, heavy artillery turrets (Turrets with 356 mm gun pairs).

Fort Drum, begun in 1909, was completed only with the replacement of its old 12-inches (305 mm) cannons by 13 in (356 mm) gun turrets in 1916. The Fort was shaped like a ship and had a “crew” of 320 men with complete living quarters, electric generators, forge, bunkers And stores that allowed him a near-autonomy.

Fort Drum (photo).

Fort Mills and Fort Hughes were built on Caballo just south of Corregidor, a quarter of the island rising to a height of 116 meters on its western side, armed with 17 pieces ranging from 12 to 3in (305 to 76 mm). Four miles south of Fort Hughes was located Fort Drum.

To build Fort Drum, the engineers cut the entire summit of the island of El Fraile to the level of the water; Using rock as a foundation, they built a massive 106.70 m long by 44 meters wide bunker, battled with concrete walls up to 11 meters thick. This giant blockhouse was armed with four 305 mm (from reformed battleships) guns in two double turrets, four 152 mm, and a three-piece anti-aircraft defense of 76 mm.

The southernmost of the fortified islands was Fort Frank on the island of Carabao, just 500 meters from the shore of the province of Cavite. Carabao was 30 meters high, straight out of the sea and was armed with 12 and 3 inches guns, covering the beach of Cavite. And sout of the Bataan peninsula was Corregidor.

On paper, Corregidor looked formidable. Fifty-six coastal guns ranging from 3 to 12 inches (75 to 305 mm), all in fortified bunkers or positions. Two 12-in guns covered 15 miles, twelve 6-in were deadly accurate at 2 miles, and the area was also covered by ten mortars of the same caliber. Nineteen other 5.5 in (155 mm guns) the “long tom”, also had a reach of 17,000 meters. AA artillery consisted of twenty four 3in (76 mm)/48 caliber, many 0.5 in cal. (12.7 mm) heavy machine guns cal, and five 3in night projectors.

The Westwall

(In writing)

Naval Fortifications of the cold war

(In writing)

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