Herdla Torpedo Battery – Defending Bergen in WWII and the Cold War

Despite overshadowed by the natural beauties of Norway, the heritage of the rich war history of this Country would really deserve a dedicated trip. Thanks to its geographical location, this Scandinavian Nation had a primary strategic role both in WWII and the Cold War.

Hitler’s Third Reich military forces conquered Norway early in WWII (Spring 1940), gaining an effective stronghold for launching sea and air patrolling missions over the Norwegian Sea and the northern Atlantic. The long coastline stretching from the Skagerrak strait up to North Cape was made impenetrable to enemy invasion, building anew a capillary network of fortifications – the Atlantic Wall. This masterpiece of military engineering was based on an extensive catalog of reinforced concrete standard elements (Regelbau in German), ranging from fortified casemates to radar towers, to observation and target range finding stations, to bunkerized gun batteries, etc. These elements were assembled in larger fortified compounds, placed in key strategic locations along the coast or in the narrow firths reaching to major ports and towns, like Bergen or Trondheim.

Typically run by the Kriegsmarine (Navy) or Luftwaffe (Air Force), these forts may comprise measuring stations, anti-shipping guns, anti-aircraft cannons, plus barracks, services, ammo storages, and even airfields in some cases. They were built not only in Norway, but having been originally planned by the Third Reich to protect the entire coast of conquered continental Europe, they were erected along the shoreline also from Denmark down to France.

As a matter of fact, many of the Norwegian fortresses of the Atlantic Wall rank today among the most massive and well-preserved of the entire line (see here for some highlights).

But the war history of Norway, and of its mighty military infrastructure, didn’t stop with the end of WWII. With the start of the Cold War, Norway became a NATO founding member, and once again of great strategic value. It found itself in close proximity to the USSR, and with a long coastline facing the sea corridor taking from the highly-militarized Murmansk and Kola Peninsula (see here) to the northern Atlantic.

Most of the Atlantic Wall forts, especially anti-shipping and anti-aircraft gun batteries, were obsolete by the 1950s, and were soon deactivated. Some were abandoned or, when retained by the Norwegian military, they were modified to cover new functions.

In a few cases, the original mission of the site by the Third Reich was retained by NATO forces in the Cold War. This is the case of the torpedo battery in Herdla.

The fortress of Herdla was a major strategic fort in the Atlantic Wall, allowing to keep a watch on the entry point to the inner waters leading to the large industrial and military port of Bergen. Thanks to the morphology of the area, featuring a rare spot of flat land nearby a steep and rocky cliff, an airfield was installed by the Third Reich besides a set of bunkers, effectively hidden in the rocks. A land-based torpedo battery, consisting of a range-finding and aiming station and torpedo-firing tubes, was part of the fort.

During the Cold War, it was decided that the torpedo battery could be still a valuable asset, and Herdla was retained by the Norwegian military – by comparison, the airfield, too short for the requirements of the jet-era, was not. Over the years, the torpedo battery was potentiated to keep up-to-date against the technological offensive capabilities of the Eastern Bloc, and to exploit the most modern identification and surveillance techniques.

The torpedo battery was part of a larger naval fort, which controlled also the barrier of sea mines implemented to stop a sea-based intrusion towards Bergen.

As a matter of fact, the area control functions and the offensive capability of Herdla were retained until the early-2000s, when the fortress was deactivated following the end of the Cold War and defense budget cuts.

Luckily however, the often neglected Cold War chapter of warfare history has in Herdla a valuable asset – an accurately preserved fortress regularly open for a visit. A modern visitor center welcomes the more curious travelers, leaving Bergen towards the remoteness of the coast. It retraces the WWII heritage of the Herdla site, thanks to an exhibition centered around an original Focke-Wulf FW190, recently salvaged from the bottom of the sea, and with a special history to tell. Then a visit to the battery, looking like it had just been left by the military staff, is a unique emotion for both the specialized war technology enthusiasts and the general public as well.

The following report and photos is from a visit taken in Summer 2022.

Sights

As outlined in the overview, the Herdla site today is centered on two major highlights. One is the visitor center, with the preserved relic of a unique Luftwaffe Focke-Wulf FW190. The other is the former torpedo battery and Navy area command bunker, Norwegian facilities installed during the Cold War in bunkers dating to the Third Reich era.

Visitor center & Focke-Wulf FW190 exhibition

The relic of a Focke-Wulf FW190 A-3 German fighter from WWII is hosted in a dedicated room, where a scenic lighting makes this impressive exhibit literally shine.

This exemplar of the iconic Third Reich fighter, produced in some thousands examples, and now almost impossible to find especially in Europe, is ‘Gelbe 16’ (which can be translated in ‘Yellow 16’) of 12./JG5, and its history is deeply related to Herdla.

It took off on December 15th, 1943, from the airfield the Luftwaffe had established on the flat area now lying ahead of the visitor center, at the time a very active German airbase.

Following troubles with the engine, it ditched in the cold inner water near the island of Misje, some ten miles south of Herdla, the pilot being able to abandon the doomed aircraft, and being saved by local fishermen – and returned to the Luftwaffe, who had a Norwegian resistance prisoner released in acknowledgment.

The aircraft sank to the bottom of the sea, but its memory was not lost by some of the locals, who clearly remembered the events. The Focke-Wulf remained there for 63 years, but it was finally located and pinpointed by the Norwegian Navy, instigated by local interest, in 2005. After preparatory work – including exploration dives, to assess the condition and to set-up recovery operations – the fairly well-preserved wreck was lifted to the surface on November 1st, 2006, and loaded on a tug. Conservative restoration work then took place in Bergen.

Instrumentation and the machine guns were all recovered, together with many further fragments of equipment. Interestingly, evidence of repaint was found during conservation, retracing some previous assignments. Yet the history of this very exemplar remains difficult to write in its entirety.

Finally, following completion of conservation works, a new home for the aircraft was prepared in Herdla, where a hangar was built anew – and this is where you can see it today.

The aircraft is in an exceptional state of conservation, considering it spent 63 years in sea water. The fuselage, wings and tail are not significantly damaged, with just some paneling having disappeared on tail control surfaces, due to corrosion. The swastika on the vertical stabilizer is still perfectly evident, like other painted details.

The propeller blades are all bent downstream, as typical for an emergency landing carried out without the landing gear and the engine still running. The tail wheel is there with its original tire, the emblem of the German brand ‘Continental’, still in business today, being clearly noticeable.

The instrumentation from the pilot’s control panel has been put on display separately. Also a gyroscope has been found. Everything is only slightly damaged. Similarly, the two machine guns, dismounted prior to lifting the aircraft from the sea, are little damaged, and displayed with some ammo.

Complementing the exhibition are a few other pieces from other wrecks, as well as some quality scale models and dioramas portraying Herdla in the days of Third Reich tenancy.

Torpedo Battery

Access to the torpedo battery, which was built in WWII just above sea level, is from a gate on the land side. From outside, the bunkers in the fortress of Herdla appear especially well-deceived in the rocks of the cliff.

What is seen today inside, however, dates to the years of Norwegian tenancy. The facility was updated in several instances during the Cold War, the last in the 1990s. Immediately past the gate, you get access to a modern and neat mechanics shop, where a partly dismounted torpedo allows to have a suggestive look inside this marvelous weapon.

Interestingly, Norway inherited and went on operating a significant number of German G7a (TI) torpedoes. This was the standard torpedo employed by the Kriegsmarine since 1934, and with some modifications (‘TI’ standing for ‘first variant’, the later variants bearing other codes), for the full span of WWII.

Propulsion power for this torpedo was from a piston engine, fed by high-pressure vapor obtained by the combustion of Decaline with compressed air stored onboard, mixed in a heater (i.e. a combustion chamber) with fresh water, similarly stored in a tank. The resulting mixture fed a 4-cylinder radial piston engine, driving two counter-rotating propellers. The exhaust in the water produced a distinctive contrail of bubbles, and the presence of a high-frequency moving mechanism had the side-effect of a significant noise emission. The head of the cylinders can be clearly seen in the dismounted exemplar.

Guidance was provided by rudder steering controlled with the help of gyros, whereas depth was controlled via a mechanical depth sensor. The torpedo could stay close to the surface or keep an assigned depth. In WWII the torpedo had no homing device – i.e. it was ‘blind’, thus requiring carefully putting it on a target-intercept trajectory. It could however cover pre-determined trajectories of some sophistication. The set-point selection for guidance and the yaw regulation gyro assembly have been taken out of the torpedo, and can be checked out in detail.

The range could be selected before launching, and was traded off with speed. It could be between 5.500 and 13.200 yards, and the speed ranged between 44 kn and 30 kn correspondingly. The German origin of the torpedo on display is betrayed by the writings in German on some parts.

Leaving the workshop through a gate towards the inner part of the bunker, a roomy supply storage area can be found, with some interesting material including torpedo parts, as well as a torpedo launching cannon.

This item represents the primary way of launching torpedoes in the early Cold War from land-based batteries or ship decks. This was a technology inherited from WWII, when coastal batteries of the Atlantic Wall ejected torpedoes from slots in the bunker wall, shortly above the surface of the water, employing cannons similar to this one (which dates from the Cold War period), thanks to a burst of compressed air. This cheaper, but less ‘stealthy’ and accurate launching procedure, was replaced by underwater launching tubes only over the years of the Cold War, featuring an increase in the level of sophistication of warfare. Correspondingly, the slots in the side of the torpedo battery bunker facing the water were bricked up, and torpedo cannons were retained mostly for use from the deck of warships.

From the storage room you get access to the core area of the battery. This is through a decontamination lock, with gear for anti-contamination testing, including paper strips for checking contamination from poisonous gas.

The battery features two diesel generators for electric power, employed in case of disconnection from the regional grid.

Less usual – for a military facility – is the presence of two air compressors. Compressed air is relevant for torpedo operation, being employed for the launch burst from the torpedo tube, as well as for propulsion and gyros in the G7a torpedo. The air compressors in Herdla are made by Junkers, solid German technology from 1961!

A few bunkerized resting rooms for the staff manning the battery can be found in the same area, besides the power/compressed air supply room and the torpedo room. The resting rooms are minimal as usual, with suspended berths, and much personal military equipment on display – coats, blankets, medical kits, and more technical material.

Finally, the core of the battery is the torpedo room. This is much longer than wider, access is via the short side. In the Third Reich years, the launching slot was on the short side to the opposite end of the room, right above the water. Today, this slot has been bricked up, and there is no window at all.

The torpedoes are aligned on racks along the long sides of the room. The launching system is via two underwater tubes, which are accessed via obliquely mounted hatches, one to each side of the room at the level of the floor. The section of the racks closer to the entrance door is actually a pivoting slide. The slide could be pitched down, thus allowing the torpedo to slip through the hatch in the firing tube. The original launch control console can be found to the right of the access door – in a mint condition, it looks really like it had just been put in standby following a drill!

Over the years, the stockpile of G7a TI torpedoes was upgraded especially in terms of guidance. The major modification was the adoption of wired control. This is based on a thin electric cable unwinding as the torpedo proceeds along its trajectory, keeping it linked with the launching battery. This upgraded model is called G7a TI mod 1. Control via a steering joystick and trajectory monitoring system could provide manual guidance to the torpedo, thus sharply increasing the chance of target interception. This technology is still in use today. Wire tubes can be found on top of the rudder of torpedoes.

Besides the G7a, Herdla battery received the TP613 torpedo, a weapon developed in Sweden in the early 1980s from previous designs. Exemplars of this torpedo, still in use, are visible in the torpedo room. In terms of mechanics, the piston engine of this torpedo is powered by the reaction of alcohol and Hydrogen-peroxide. In terms of guidance, this torpedo features improved wired communication for guidance and power setting (i.e. changing torpedo speed during the run), as well as passive sonar homing. A dismounted section exposing the engine can be found on display.

The wire tube installation on top of the rudder is featured also on this model, and examples of the wire are on display.

The original guidance console, made by Decca, with a prominent joystick on it, is on display as well!

Training and proficiency checks are typically carried out without a warhead, but with an instructional head. Distinctively painted in shocking red, and with powerful lights in them – to show their position to simulated targets during training exercises, when needed – these are on display in a number. Since the torpedoes, just like missiles, are very expensive, a way of recovering them after instructional use has been envisioned, in the form of inflating bags coming out of the head, increasing the buoyancy of the emptied torpedo and forcing it to surface when reactants tanks are empty and power is off.

Offensive warheads can be exchanged with dummy ones for training, bolting them to the body of the torpedo, which remains totally unchanged. A warhead with a 600 lbs explosive load, triggered by a proximity pistol, was typically put on G7a torpedoes. The proximity pistol was made of four petals, which on contact with the target were bent towards a conductive metal ring around the nose cone of the torpedo, closing an electric circuit and triggering the explosion.

Leaving the torpedo room and the bunker is via the same way you came in.

Sea Mines & Area Control Center

But your visit is not over. As mentioned, the Herdla coastal battery hosts an area control center, with provision to manage target detection facilities and the minefields in the waters around Bergen.

This part was built in a facility strongly potentiated with tight doors, typical to the shockwave-proof military construction syllabus of the Cold War. A sequence of roomy vaults carved in the rock hides a number of containerized modules, together with an exhibition of sea mines and related apparatus.

Most notably, an L-type Mk 2 moored mine and a Mk 51 bottom mine are on display, with a understated control panel. The latter is actually a portable controller for triggering the mines. Already before WWII, sea mines were often put on the bottom of the sea in shallow waters, or moored in deeper waters, to control access inner waters, firths, ports, etc. The Germans made extensive use of this technique in Norway, and following WWII this strategy was inherited by Norway to protect its waters from (primarily) Soviet intrusion.

Despite contact mines were still popular in WWII, they have been surpassed and gradually replaced already in that age by proximity mines, based on noise and – especially – magnetic sensors. Today, proximity fuses activated by the magnetic field of ships or submarines passing nearby are standard technology. Onboard electronics allows to distinguish between the magnetic signature (i.e. fingerprint) of different ships, thus avoiding any issue for civilian or friendly traffic, and activating only against enemy shipping. Degaussing techniques – i.e. the ability of military ships to hide their signature – have forced to improve detection technology, which is today extremely sophisticated.

Furthermore, for the protection of ports and friendly waters, sea mines are typically controlled and triggered by hand, upon detection and localization of enemy shipping, by means of dedicated detection facilities on land or water. This improves precision and allows more flexible defensive-offensive tactics, since a human chain of command has control on the minefield, instead of a pre-determined computer program.

To trigger the mines, consoles like that on display are employed, where a trigger for each mine allows precise control over the minefield.

The first containerized control center hosts a similar, yet much more modern, dedicated console. Everything in this movable control center is very neat, and really looking like reactivation might take place in just moments! Of interest is also the situation map, covering the area around Herdla and the water inlet to Bergen.

A nearby container reveals berths and a small living area for stationing staff.

Yet another container hosts a complete situation room covering the area. Similar to the coastal battery in Stevnsfort, Denmark (see here), a careful eye was constantly overlooking the shipping in the area.

In the same container, a console for steering torpedoes, more modern than that previously seen in the torpedo battery, is on display.

All in all, Herdla is a one-of-a-kind destination, of primary interest for those interested in Cold War military history, enjoyable and easy to visit. Totally recommended for everybody with an interest in history, with much to see and learn for the kids as well.

Getting there & Visiting

Herdla fortress features an official visitor center with a large parking area, and amenities including a small restaurant and a shop. The official website is here. It can be reached about 27 miles north of central Bergen, roughly 45 minutes by car. The address is Herdla Museum, Herdla Fort, 5315 Herdla.

The torpedo battery and control bunker can be visited only on a guided tour. Visiting from abroad, we scheduled an appointment, and were shown around by the very knowledgeable guide Lars Ågren, a retired officer of the Royal Norwegian Navy. He joined the Navy in the late 1970s, in time to gain a substantial, hands-on Cold War experience during the final, high-tech part of that confrontation. He was promoted to tasks in the NATO headquarters in Belgium, later returning to Norway, and totaling more than 37 years in service. He is strongly involved in the management of the Herdla site. Chance is for you to embark on a visit with this guide, or other very competent guides who will satisfy the appetites of more committed war technicians and engineers, being capable of entertaining also the younger public as well.

A visit to the torpedo battery and control center may last about 1 hour. Seasonal changes to opening times may apply, as common in Northern Countries, therefore carefully check the website.