Minelayer Submersible (1925-44)HSwMS Valen (1925) was a unique boat in class, and only minelayer submarine of Sweden when WW2 broke out, but she was a prioneer leading to the construction of six more during the war. She was based on the Bävern design, that is, based in turn on the German WWI UB-III design. It was designed entirely in Sweden and had the French Normand-Fenaux minelaying system in place, with two mines per well, ten total in external ballast tanks between the pressure and outer hull, She was tested abundantly to demonstrate the concept and stayed in service from 1925 up to October 1944 when decommissioned as a new generation of minelayer submarines, the Neptun class, was entering service. In between her design inspired the Delfinen class (1934).
Development
The concept of minelayer submarine was pioneered by Sweden’s old rivals, the Russians, all the way back to 1905 but the Krab only entered serive later in WWI and in between the concept had been superbly demonstrated in WWI when the Germans unveiled the small but deadly UC-I class. The latter were rail-transportable submersibles based on the UB-I design, they were short range and carried only a handful of sea mines, yet the tonnage they sank in two years came as a shock to everyone. However not everybody jumped in the bandwagon. By 1919, Sweden like other nations got more informations on both the UB-III and UC-III designs, which helped creating its post-Holland designs such as the Hajen and Bävern classes, the first launched in 1917 and the second in 1921.
Back in 1921 also, the naval staff expressed the need of a minelayer version of the new Bävern design, which seemed large enough for the task. The task was given to the Royal Karlskrona Navy Yard and arsenal design bureau (engineer name unknown).
The Hajen (left) and Bävern class (right). The second design was used as base for the Valen.
What was done essentially was a Bävern class modified with with ten vertical mine-laying tubes of the French Normand-Fenaux system (itself based on war reparation UC-III type and used on the later “jewel” class (1928). These tubes were installed along the ballast tanks and their integration was the main task of the engineers, which otherwide kept the Bävern hull largely unaltered to gain time in research and development. Amazingly, HSwMS Valen would keep its main armament intact, with four 457 mm (18 inches) bow torpedo tubes and a 75 mm (3 inches) deck gun and add to this later a 25 mm AA gun to boot. So on paper, such submarine could mine restricted Swedish waters to interdict access to an enemy force, like the island maze of its Baltic southeast coast, while keeping its patrol capacity intact. If it works, Sweden was likely to order more of these, even make it its main “do it all” submarine type instead of relying of specialized submarines. However on an engineer’s perspective there were still tremendous challenges.
First off, the space for these ten tubes had to be found, and depending if they were wet or dry wells, in addition to the the right delivery system, the remote fuse setting with the technologies of the 1920s would be problematic, and the buoyancy needed to be completely reworked to not loose the submersible’s balance. The weight of the mines for example, once dropped, needed trimming ballasts to compensate and avoid broaching the surface. Some systems like horizontal mines tubes allowed a surface night minelaying operation, but if used more agressively to blockage an enemy port or close important waterways like river mouths and estuaries, clandestined operations were necessary, so it needed to be done underwater, like the Germans did, going far into the Thames estuary for example.
However these questions were resolved, without the help of the German clandestine submarine design bureau at the Hague (IWs) and the new design was approved in early 1923, for a laying down of the keel later that year (date unknown), a launch and completion in 1925, with fitting out between May and September. As seen above, the experimental groundworks had been laid and the trials of HSwMS Valen would help creating the next design, the Delfinen class (laid down 1933) using the same system whereas the general hull design was updated to the Draken standard (1926).
Design of the class
Hull and general design
Model of the Valen, Public domain in Sweden, credits: digitalmusem.org and kulturnav.org
This design was very similar to the Bävern, with an overall length of 57.10 metres (187 ft 4 in), a beam of 7.11 metres (23 ft 4 in), and a draught of 3.10 metres (10 ft 2 in). Lenght was the same but the beam went from 5.82 m (19 ft 1 in) to 7.11 metres due to the integration of the mine wells into the outer hull. Due to this extra buoyancy, the draft was reduced, since it was of 3.51 m (11 ft 6 in) on the Bävern. The great unknown was about the choice of powerplant, since a wider hull would cause extra drag, and thus, reduced top speed. The displacement was unsurprisingly superior as well, going from 472/650 tons to 548/730 tons which was quite substantial. To be exact she displaced 501 tonnes surfaced, unloaded. 47 tonnes more when loaded, surfaced, and 730 tonnes submerged. For the general outlook, see the Bävern class.
Powerplant
She was propelled by two propellers, bronze, 3-bladed, fixed pitch, and the shafts were driven by a pair of Atlas diesel engines rated each for 670 bhp (500 Kw) for a total of 1,340 brake horsepower (1,000 kW)
In contrast the Bävern class had 2,100 brake horsepower (1,600 kW) with their 6-cylinder diesels. The Atlas diesels were Swedish, from a venerable engineering company founded in 1873 as Atlas (renamed Atlas Diesel in 1917) that eventually became the global industrial group Atlas Copco in 1956 after ending its diesel engine production. They had been designed by Jonas Hesselman, who worked for AB Diesels Motorer (which merged to become Atlas Diesel in 1917). Hesselman pioneered the airless (direct) fuel injection system for 2-stroke and 4-stroke marine diesels. Known commercially as “Polar” diesels, these engines were globally renowned in the 1920s for being remarkably lightweight and power-dense for their time, making them highly desirable for the cramped engine spaces of submarines and polar exploration ships.
They procured Valen a top speed of 14.8 knots (27.4 km/h; 17.0 mph) surfaced and a range estimated to 3,000 nautical miles or 5,556 km at 14 knots. When submerged she had two electric motors from Luth & Rosén Elektriska AB which were rated for 350 hp, or 700 horsepower (520 kW) total for a top speed when submerged of 7.4 knots (13.7 km/h; 8.5 mph) and her batteries provided a range of 54 nautical miles (100 km) at 6 kts underwater. For her batteries of Lead-Acid (“ackumulatorer”) they came either from Tudor or Jungner and to keep consistent with UB-III layout they likely had 120 cells divided into two separate battery banks of 60 cells in the forward and aft sections under the deck. Valen could dive circa 60 m or 180 feet.
Armament
75mm/49 K/50 m/12 or 75mm/23 m/16
75 mm/23.7 cal. kanon M/16 was a Swedish naval deck gun manufactured by Kongsberg Våpenfabrikk or associated Scandinavian contractors, featuring a barrel length of 23.7 calibers. It was used on the Hajen II-class Submarines and Bävern, fitted as primary deck artillery on Royal Swedish Navy submarines to povide warning shots or engage unarmored targets when surfaced. No specs details.
Torpedoes
Exact same arrangement as for the Bävern, with four bow tubes, four torpedoes in reserve. Either the Torped 14, or its derivative the Torped 27 for submarines in the interwar. Both were thread-steered, with a plate of a thin copper wire through which it was able to provide control signals to the torpedo. However they might be the 45cm UV Stävtub m/93, 3 meters long (453 mm exact diameter) or the m/04 for practice and more likely the m/12 1
Mines
She had ten well, or tubes, wet type, of a derivated design from the French Normand-Fenaux system. Each tube held two mines stacked vertically, giving her a total capacity of 20 naval moored contact mines—specifically variations of the Swedish m/22 (Model 1922) submarine-launched mine series and its immediate successors. Two per tube. These were wet-tube gravity drops, external to the pressure hull but inside the outer casing. They were held in place inside the vertical shafts and upon reaching the drop zone, the submarine would release them mechanically. The only issue is like the German UC types of WWI they were preset before departing port. Meaning if there was a change of minefield location it should be similar or close enough as the mines would be preset the same to achieve the desired depth. However the system was reliable enough to be repeated on the next designs.
25mm/55 K/58 M/32 (1930s)
Installed in the later 1930s this AA gun was manufactured by Bofors and located not on her aft platform, of the CT fairing but on deck aft as seen in the museum’s model.
Barrel Length originally 64 calibers /55 or L/64 depending on measuring conventions.
Rate of Fire: 160–180 rounds per minute.
Muzzle Velocity: 850 m/s.
Ammunition: 25×205mmR rimmed cartridge. Later shorter 25×187mmR casing
The M/32 scaled down the foundational architecture of the 40 mm Bofors, employing the same long-recoil operating principle and a hydro-spring recoil mechanism. It was fed continuously from the top using 6-round clips placed side by side into a vertical feed frame. The clips were designed in splitting halves that fell away as the cartridges slid into the breech, preventing interruptions to sustained fire.
Sensors
Hydrophones, no detailed type provided. Perhaps German Atlas type.
⚙ specifications |
|
| Displacement | 548 tons surfaced, 730 tons submerged |
| Dimensions | 57.10 x 7.11 x 3.10 m (187 ft 4 in x 23 ft 4 in x 10 ft 2 in) |
| Propulsion | 2 shafts Atlas diesels 1340 bhp, 2 EM 700 hp |
| Speed | Surfaced 14.8 knots, Submerged 7.4 knots |
| Range | est. 3000 nm/14 kts and 54 nm/6 kts |
| Armament | 1x 75mm/49 K50 gun, 4x 450mm TTs(8), 20 mines |
| Max depth | c60 m (180 ft) |
| Sensors | Basic Hydrophones (Atlas?) |
| Crew | 31 officers and ratings |
Career of HSwMS Valen
The launch of HSwMS Valen in May 1925. Public domain in Sweden, credits: digitalmusem.org and kulturnav.org
Unfortunately no creative commons of this submarine yet.
There is not much on this topic, like most interwar Swedish submarines. Valen was laid down at the Karlskrona Navy Yard in 1923, launched on 5 May 1925, commissioned on 4 September 1925 and started working out and training, soon followed by mock minelaying missions to test the concept. It was proven and by 1930 was formulated the need for new minelaying submarines which became the Delfinen-class, launched 1934 and their own successors by 1942, the Neptun-class trio, all retaining the same twenty mines Normand-Fenaux derived system pioneered on Valen. No details for her exercises, she was formally attached to the Bävern squadron for logistics and maintenance, but operated indepedently under direct HQ control. For nearly two decades, her career was largely peaceful but strategically valuable. She served as a proof-of-concept; her successful implementation of minelaying machinery. When WW2 started she joined regular patrol lines, with two white line markings on her hull. Photo records shows she was still in her original light grey livery. He wherabouts are not known but by 1943 already she was recoignized as worn out and since more moder submarines were inconstruction, her crew was required elsewhere. She was formally decommissioned on 6 October 1944, mothballed and sold for BU, likely in 1945 or postwar.
Read More/Src
Books
Hofsten, Gustaf von & Waernberg, Jan: Örlogsfartyg – Svenska maskindrivna fartyg under tretungad flagg. Luulaja: Svenskt Militärhistoriskt Bibliotek, 2004.
Fontenoy, Paul E. (2007). Submarines: an Illustrated History of Their Impact. Santa Barbara, California: ABC-CLIO.
Miller, David (1991). Submarines Of The World. Salamander Books.
Conway’s All the World’s Fighting Ships, 1922-1946. London: Conway Maritime Press. 1980.
Links
navypedia.org
vhfk.se
wiki EN HSwMS_Valen_(1925)
hhogman.se/