Spiggen 1958. Ref 1
Spiggen 1958. Ref 1
Swedish submarines since 1904
Text and pictures Björn Bellander Pictures current 2013
Swedish version  Back
since 060105

© Björn Bellander


Brushnell's TurtleHajen IHvalenDelfinenAborrenHajen IIBavernUlvenNordkaparenSjoormenU1 - U9Hajen IIIDraken ombyggnadSjoormen II, NackenSodermanlandSpiggen I-IIGotlandHedemora V12AUBHedemora Ran V18BUBHedemora Industrial enginesLinks

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Swedish version

Nordenfeldt's first trials and others

Thorsten Nordenfeldt. Ref 49
Thorsten Nordenfeldt. Ref 49


Diver clock




Below pictures from Marin museum Karlskrona.

Leonardis undervattensbåt. Ref. 1
Leonardo ritdring construction of a submarine boat. Ref. 1.
Leonardis båt?. Ref. 1
Copy of the Leonardo sub? Ref. 1
Info om Leonardi och ubåtar. Ref. 1
Info about Leonardo and submarines. Ref. 1
David Bushnells båt. Ref. 1
David Bushnells sub. Ref. 1
H.L.Hunley konstruktion från 1860. Ref. 1
H.L.Hunley construction from 1860. Ref. 1
John Hollands ångbåt. Ref. 1
John Hollands steam cub. Ref. 1
Dykarklocka. Ref. 1
Diving clock. Ref. 1

Brushnells submarine. Ref 49
Bushnell´s trial to fasten a bomb on the ship Eagle 1775 in the harbor of NewYork.

First some history.

The interest to investigate sunken submarines and eventually bring up valuable things have always been actual.

Most part tell about in the 1700 th. From these years there are written reports. In this era the merchants and warships had been developed and there are also economy in salvaging.

Sweden was well ahead and written reports have shown, but the knowledge had to been taught by traveling in Europe in order to study the technics which was found.

The very first ideas can be found from 384-322 b.c through written papers by Aristoteles. He had ideas about a clock which was used under water.

A paper from Rome 1599 describes one trial to salvage the ship of Caligula which was wrecked on the lake of Niemi in Italy.

This construction of sub water clock was improved and 1616 Franz Kessler had ideas with round windows and the diver sitting inside. As many other ideas it was not realized.

The first known which was used was in England 1665. The wreck was a Spanish ketch, which had explode1588 in Tobermory Bay. Of course the interest was to find guns. They were supposed to be very valuable.

1689 the ideas showed to supply the clock with fresh air from above. The way it was carried through was to pump air from the surface. The technics was by using bellows to force air into the clock. But this important thing with oxygen was not understood until 1796 when the Swedish chemist discovered this matter.

The first one in Sweden who used an user friendly clock was Mårten Triewald 1728. He improved the idea from the astronomer Edmund Halley.

There was the possibility to salvage the Ship of the line Wasa. But they didn't knew this until 1956 when trials started to salvage the ship for real. It was found that most guns had already been salvages and that there were also documents which showed that guns had been exported 1665.

Albrecht von Treileben had got the privilege from Karl X to act with diving on scene of the accident.

This was as far as the under water clock could be used. Modern trials were done 1980 on the place where the Ship of the line Kronan exploded outside south cape of Öland. This clock was newly manufactured after an old original. It was proven to be useful.

I Connecticut USA David Bushnell manufactured a variant of a diver's clock 1775. This was manual driven by outside screws. The meaning was that just under the water surface  move it up to an English ship in the harbor and there fasten one time controlled bomb. This he had invented. Sorry to say all his trials were in vain. The equipments to fasten the bomb didn't function. A copy of this invention is exhibited at US Submarine museum in Groton. Bushnell died 1824.

In England 1878-79 two prototypes of submarines were built equipped with steam engines. No 2 sank when moved. A copy of this boat made 1997, called Resursgam, can be seen at Birkenhead, Wirral.

Ideas in Sweden about vessels which was able to move under water are documented 1840 by Claes Rudolf Carslund. He wrote to the Marine ministry that he had such an idea. One model was built later but the whole project was judges a unrealizable.

First known, when a prototype was build was made by Sandahl, who on the navy shipyard build a submarine called "Sandahl's canon". He built several different variants, but none could show the functions which were expected.

Not until Thorsten Nordenfeldt started to make reality of his ideas things begun to be interesting. From his office in England where he spent time to import iron and he came in contact with a vicar, Garret. He had ideas about submarines. This boat was later built at Bolinders at AB Palmcrantz & Co in Karlsvik Kungsholmen Stockholm 1880.

This man Nordenfeldt was one of the great inventors in Sweden and developed working methods for Swedish works and factories for weapons. This was done from his office in England.

His submarine with his Garret cooperation was ready 1883. and the power supply was from a steam engine. This sub could only be able to sail on the surface and had difficulties to stay under water. It was later sold to Greece. Another two submarines were constructed and built by Garret in England. They were sold to Turkey. No 4 was manufactured for the Russian marine, but it sank outside Denmark during transport to St. Petersburg. Must be able to salvage.

Nordenfelt was forced to bankruptcy in England and moved then to France. Here he produced supplies for canons. 1903 he moved back to Sweden, withdraw and died 1920.

There are many more sub pioneers, but these were some. Several authors have written about the first one under water. If one read these there are almost as many firsts as authors.

The Resursgam. Ref 49
The Resursgam. Ref 49

Nordenfeldt submarine sold to Turkey. Ref 49
Nordenfeldt submarine sold to Turkey. Ref 49

Page 1


Swedish version

Hajen 1 1904


AB Atlas

JV Svenssons


Vasa bridge

Info about submarine no 1 1904. Ref 1
Info about submarine no 1 1904. Ref 1
Info Shark no 1. Ref 1
Info Shark no 1. Ref 1
Prop, rudder Sub 1. Ref 1
Prop, rudder Sub 1. Ref 1
Hajen 1 i ubåtshallen. Ref. 1
Hajen 1 moved into the new submarine hall. Ref. 1
Nya ubåtshallen på marinmuseum. Ref. 1
Overview over the submarine all at marin museum Karlskrona. Ref. 1
Submarine  no 1 The Shark outside Marine museum in Karlskrona. Modenized 1916. Ref 1
Submarine no 1. The Shark outside Marine museum in Karlskrona. Modenized 1916. Ref 1
Useful submarines were not to be interesting until the technical knowledge about joining of iron constructions and power supply had reached the level which could make the ship able to use. This was not until beginning of 1900. Earlier almost all warships had been built by wood.

1902 the Swedish navy got a provision of 400000 Skr to build a submarine. During building of war equipments all orders always follow changes in specifications and equipments.

The engineers at Marine ministry had now to construct a sub. This team was led by Carl Erik Richson.

Richson was born Eric Ericsson and changed name 1882. His youth is alike Gustaf Dahlén who also was born in a farmer's family. Richson was talent and his education was arranged by the owner of farming land around. General Lieutenant Sprengtporten.

One of his first works was at Atlas Works in Nacka. Here railway components was produced. This firm became later the owner of the similar producer in Sodertalje. The future Scania-Vabis.

In Stockholm the bridge Vasa Bridge was going to be built 1878 and the design which won the contest came from Atlas. The order went there. This work was done by Richson. He used the new technic to cast under water. This was a patent from USA which was sold in Sweden.

All drafting stuff was manufactured at Atlas Works. This bridge was main and important for traffic in Stockholm until 1935 when Central bridge was built. This bridge is as many know a temporary arrangement, still 2014.

Richson emigrated to USA. Here he got different engagements and lastly at the marine yard in New York. Here he worked as the chief of drawing office.

He returned to Sweden 1897 and became engage at Marin ministry 1899. Now he was sent back to USA in order to study buildings of submarines. This because that a new type of sub had been constructed.

This journey became the main knowledge for his work when his came back to Sweden, in order to construct the sub Shark 1901-1903.

His work in the future became to handle the basis for every submarine in Sweden up to 1928.

The main principle for Shark no 1 was the kerosene engine. It was manufactured by
J. V. Svenssons Car factory in Augustendal. This producer was specialized in kerosene engines. In Sweden over 3000 boats had this kind of engine. The factory had also a large export for Russia. May be it is understandable that Gustaf Ericsson in Surahammer chose a Kerosene engine for his first car. The only producer of cars in Sweden was Scania but they chose petrol engines. The fundamental unit for JV Svensson was the patent of Primus burner.

It was not hard to understand that Richson chose kerosene engine for the sub. Later it showed that this fuel had large problems. When this first sub was updated and rebuilt 1916 it was replaced by a diesel engine.

The Shark no 1 was active during Union disintegration of Norway. The sub had to move over to west coast  through Gota Chanel by it's own machine and connect with the Swedish rearmament towards Norway. But the military leaders didn't dare to put the sub in active duty. Instead it was at place for power demonstration.

From this moment when the Shark no 1 had showed itself within Swedish marines and also been rebuilt with a diesel engine 1916, it is considered that the Swedish submarine weapon was created.

Page 2


Swedish version


Ub No 2
Ub No 3
Ub No 4

Info Hvalen manufactured in Italy. Ref 1
Info Hvalen manufactured in Italy. Ref 1 Info Submarine 2-4 Swedish produced. Ref 1
Info Submarine 2-4 Swedish produced. Ref 1 Submarine type Ub 1-4. Ref 1
Submarine type Ub 1-4. Ref 1


Ub No 2

Hvalen manufactured in Italy. Ref 1
Hvalen manufactured in Italy. Ref 1

Now it was good times for Marine ministry and it put lots of money on submarines. They had the same problem as the army how to use air force. With the new submarines the ministry got something to be responsible for.

During the first years it was the same uncertainty how to use it. It was lucky that the torpedo already was invented and Shark no 1 was equipped with one.

The development went fast and soon there were many changes how to construct new submarines.

The marine ministry now understood that they had no more new development ideas. An investigation were done where to find the submarine new ideas. One commission with 3 persons including Richson travelled to Italy to discuss an order for a new submarine. This was done at the Fiat San Giorgi Yard. This sub got the name Hvalen.

At the same time another two boats were built. One ordered from Denmark "Dykkeren" and one for the Italian Marine. All three were equipped with petrol engines. The Italian sub explodes later.

Two Swedes made themselves to be experts in U-boats. They controlled the whole production and often didn't accepted bad workmanship from the Italian yard personal.

It was Captain Magnusson and machine man Strandlund. These two should be the leaders for system developments for U-boats, at different levels.

Why Hvalen got a petrol engine was mostly depending on that the Yard offered a speed of 15 knots on surface. Very restrictive stipulations were introduced how to act with engine and with petrol. The boat had 3 propellers and the engine was divided in 3, 4 cylinders carburettor engines. These gave a power of 275 ps from each.


The transport of the ship home to Sweden which Swedish crew under the command of Magnusson and Strandlund carried through. They sailed 4000 nautical miles, are an important. memory within the Swedish Navy. This sail was an adventure and took two months.

Already after 10 years the sub Hvalen was withdrawn from active service 1919. The ship was sank somewhere at Hårsfjärden 1924. Anyway the ministry had got good experiences from this submarine construction and the type became leading for all future boats during the lead of Richson.

The knowledge of Magnusson was  very much impressed by people at the Italian yard. and 1911 he accepted to be there representative in Argentina. He stayed there till 1914 when the WWI broke out. He returned to Sweden and worked some time at Marine ministry. 1916 he devoted to private business. He died in Stockholm 1930.

Gustaf Strandlund worked at several levels within Marine ministry during 25 years. He got several distinctions like Vasa medal and Svärdsman. Gustaf ended with pension 1932 and was appointed lieutenant.

A discussion arose what type of submarines Sweden needed. After that UB 2-4 were built. They were also equipped with 4-stroke 6 cylinders kerosene engines giving 225 ps built according to Diesel's patent. The newly started Atlas works produced them. Atlas had bought license for this type  from Germany for 100000 Sk. Note that these engines were run on kerosene. These early boats were built at Motala yard.

In February 1910 Marine ministry got a letter from Kockums yard. In this they informed that they had acquired the sole rights to produce submarines according to the patent of Fiat Laurentius. Kockums had judged that Sweden was on the way to produce many submarines.

That was the case.

Page 3


Swedish version

1914 - 1915


Reconstruction 1916 of
Hajen 1
Ub No 2
Ub No 3
Ub No 4

Info Svärdfisken, Tumlaren. Ref 1
Info Svärdfisken, Tumlaren. Ref 1 Info U-Sub Laxen and Gäddan. Ref 1
Info U-Sub Laxen and Gäddan. Ref 1
Info Ubåt Delfinen 1915. Ref 1
Info Ubåt Delfinen 1915. Ref 1
U-Sub Laxen. Ref 1
U-Sub Laxen. Ref 1
U-Sub Delfinen. Ref 1
U-Sub Delfinen. Ref 1




About MTB engines

Svärdfisken or Tumlaren. Ref 1
Svärdfisken or Tumlaren. Ref 1

Now everything happened quickly and in a few years 5 U-Subs were built. The production was at different yards. Kockums got orders for 2, both through license agreement of the Italian type. Karlskrona built 2. Furthermore Bergsund got one order to built a U-sub constructed by Kockums.

The rivalry between yards was big and the development was improving fast. Any problem to get crew was not any problem anymore. People could count to survive a underwater mission.

Kockums started to produce the U-subs Särdfisken and Tumlaren by using the license agreement with Fiat Laurentius. The drawings from Italy were already ready 1910. The name Laurentius was the name of the Yard's main constructor. Richson was the similar i Sweden. Both had total control of the submarine construction in each country.

The both Italian subs had got a modernized hull. This was divided in several pressure secure parts. Displacement was 252 ton and 2 torpedo tubes. They were equipped with two diesel engines acting on each propeller over one electrical motor/generator, from Atlas Diesel. The engines were built over the diesel agreement and were produced in Nacka outside Stockholm. This started the "weight-race" and it showed in the future new buildings up to 1948. This race stopped at about 500 tons. Both boats were decommissioned 1936.

It was decided that Sweden should have two types of submarines. Class 1 and Class 2. The first was aimed for open sea and considerably bigger. Class 2 were aimed to be used as coast boats.

The sub Laxen and Gäddan were manufactured at navy yard in Karlskrona. They were aimed to be class 2 subs with the displacement of 140 tons. Both were decommissioned 1935.

The last ship which was built during these years was named Delfinen. It was completed at Bergsunds Mechanical Works in Stockholm with the help of drawings from Kockums, which had cooperated with the Dutch yard IVS.

It was a mixture between Swedish single hull construction and the Italian double hull type. The weight became 260 tons with two torpedo tubes and was a class 2 type. It was decommissioned 1933.

In the same time all previous kerosene ships changed 1916 over to diesel fuel engines. There were 4 ships which got the new 6 cylinder diesel engines. Note that Hvalen was used lifetime with petrol fuel and carburettor engines.

The engines which Atlas had developed had 6 cylinders and got the name Polar. Amundsen had ordered this engine type for his research ship Fram.

Svärdfisken and Tumlaren got 2 engines each. They worked on each propeller axles directly. They could be reversed. This was done by changing position of camshafts just before the engine is stopped. This got the engine to run counter wise. It was only done when the need to move backwards. The electrical engine needed direct current and could only run one way. This was a system which Sweden used on one type of Torpedo boat with Isotta Fraschini engines. See Swedish link

Page 4


Swedish version



Info U-sub Aborren. Ref 1
Info U-sub Aborren. Ref 1


HMS Abborren

U-sub Aborren. Ref 1
U-sub Aborren. Ref 1

The development of submarines was now come so far that demand were forced to make areas and good conditions of living must be able for the crew. Furthermore there was a need for higher weapon capacity.

Still there was a length restriction which was forced by the possibility to move through Göta Chanel to Gotenburg.

This type got a displacement of 174 tons, equipped with 2 torpedo tubes, but also extra torpedoes for reloading.

The engine became the the well proven Polar engine from Atlas works. It had one 6 cylinder fully reversing 320 ps engine. This meant that the engine was acting directly on its propeller shaft, but on the way coupled to a generator for under water drive and one electrical engine.

Page 5


Swedish version


Hajen II

Info Hajen II class. ref 1
Info Hajen II class. ref 1


Hajen II. Ref 1
Hajen II. Ref 1

Money for these three boats had already 1914 been allowed. The ships got the displacement  of 422 tons and equipped with 4 bow torpedoes.

The engines were the new diesel motors from Atlas. They were 6 cylinders and had the power of 650 ps for 2. They could be directly reversed. This was done by a operating handle of Hesselman system.

Hesselman was manager engineer at Atlas and hade developed a type pre chamber diesel. This system gave less knockings and could give a more silent run.

For this the new fuel injection was needed. This was done by pressurized air. When starting pressurized air was used to get the engine to rotate.

These boats was built after the Fiat type and drawings were fetched during the war 1915. All were laid on keel at Kockums yard.

Sälen was launched 1918 and Valrossen in April the same year. It is notable that the Swedish panzer ship Gustaf V was launched the same year.

The cause of WWI the building of these ships were delayed and could not be delivered until 1921.

Page 6


Swedish version



Three  Bävern ships. Ref 1
Info Three Bävern ships. Ref 1


Submarines between the wars.

Mine layer Uttern. Ref 1
Mine layer Uttern. Ref 1

The ministry had sent a delegation to Germany in order to study new developments of submarines.

This journey was meant to result in an order for Krupp-Germania yard in Kiel. They could not accept because large orders of warships from the German Reich.

Instead this order went to AG Weser i Bremen. This ended with boats of Bävern type and the displacement 472 tons. It was double hull ship divided into 5 pressure secured units. It was equipped with 4 bow torpedoes.

This ships were later built at Karlskrona yard and Kockums got because they had lack of fundaments one. This last fundament was aimed for smaller ships, but it was rebuilt to take the last Bävern boat.

All these boats got the same engines 2 of total 650 ps at 459 rpm. Just like Hajen II.

All were decommissioned 1943-44.

Page 7


Swedish version

1926 - 30 Valen 1925

Submarine Ulven. Ref 1
Submarine Ulven. Ref 1 Mine layer Valen from 1925-44. Ref 1
Mine layer Valen from 1925-44. Ref 1


Submarine Ulven. Ref 1
Submarine Ulven. Ref 1

Between Bävern and the Draken boats, the interest came to get mine laying boats. Richson constructed 1922 this type as a development from Bävern type. They became a bit larger with 548 tons 4 torpedoes, 25 mm machine gun, two folding down periscopes and 10 places for 20 mines.

Valen was built in Karlskrona and delivered 1925 and was decommissioned 1944.

All these boats got 6 cylinder diesel engines built at Götaverken on license from Burmeister&Wain. They had in turn license from Augsburg-Nürnberg-MAN. This engine type had 900 ps at 450 rpm and were started by compressed air. These engines were the last engines that didn't were equipped with exhaust turbines for inlet air.

On these submarines for the first time torsion oscillations caused by the engines revolution. The power on these boats had reached a critical border.

One crankshaft break happened also. This problem caused great activity and was later solved by rotating weights in the ends of crankshaft.

The ships had a displacement of 667 tons and considerable more powerful armed. 4 bow torpedoes tubes 540 mm. One directed rearwards, 540 mm, one 10,5 cm canon placed on front deck and one 25 mm air defense canon.

Earlier the submarines were equipped with a telephone a breathing system device in order to be used when free saving.

These ships were delivered 1928, 29, and 31. Ulven became the most well known one when it sank by an exploded mine outside Gothenburg 1943. Gripen was used after 1947 as a rescue boat. The Draken was the boat on which snorkel trials were done after the salvage of the German sub 3504 1946 . It was decommissioned 1948.

Page 8


Swedish version


Delfinen II

Delfinen class. Ref 1
Delfinen class. Ref 1
Springaren. Ref 49
Springaren. Ref 49



Delfinen II


Hunting boat Delfinen. Ref 1
Hunting boat Delfinen. Ref 1

After the building of mine layer Valen it was realized that one of this type was not enough for the needs.

The Valen showed to by a good combined mine layer build on the knowledge from Bävern. Construction drawings were now ordered from IVS in Holland on the alike torpedo sub boat, minimized in weight and dimension.

The result became a 540 tons heavy boat of which 2 were build at Kockums. Another one was ordered next year.

They were built on the same security level as Valen equipped with salvage lock for use in an accident.

For defense there was one 57 mm and one 24 mm canon. The 4 torpedo tubes were arranged that 2 were direct forward and 2 rearwards. Furthermore 2 rescue, 2 dingy for rescue.

The ships were equipped with license diesel engines built at which Kockums had license from a Man construction. Two 7 cylinder were mounted in each boat. They gave a power of 570 ps at 490 rpm each. They were equipped with direct injection by pumps working at high pressure.

These submarines were decommissioned 1953 except Nordkaparen which was rebild beginning of 1960 and 1988 spared as a museum boat in Gothenburg.

The developments of diesel engines have now reached almost the end as they were equipped with all those extra parts future engines later got. The rpm was now over 500, fuel injection was done during high pressure.

All these system had now to be updated. One disadvantage became that the more cylinders the longer engine. This was solved by constructing V engines.

Page 9


Swedish version


Svärdfisken II

Info type Sjölejonet. Ref 1
Info type Sjölejonet. Ref 1


Svardfisken II
Tumlaren II

Sjohunden and Harsfjadern

Hedemora Diesel

Sjölejonet. Ref 1
Sjölejonet. Ref 1

The world was in a state of agitation and Marine ministry had an agreement from 1927 to build another 3 boats as compensation.

There was a newly developed submarine on the ground from Delfinen. This construction had reduced dimensions down to 580 tons. 3 were ordered from Kockums 1934.

This type had 3 torpedoes in bow and one in rear end and also one double unit external the hull placed in the rear part of the ship. Totally 6 torpedo tubes. In the rear part of the sub tower  there were 2 40 mm canons which were able to be sunk down in a store part of the pressure secure area.

All boats now got 2 8 cylinder (Delfinen 7) MAN-Kockum diesel engines, giving 950 ps at 510 rpm. They had the possibility to perform 17 knot surface positions and 9 knots sub surface. This boats was alike the German  VIIC, which was the workhorse for the German submarine fleet.

The first three were delivered 1938-39. When war broke out all were in a hurry. A program for more boats to be built at Kockums was activated and another 6 of the Sjölejon type started to be built 1940-52.

Because of the large series, according to submarines, it became short delivery times. These boats were built in record breaking time, 12-15 months each.

All these boats of the type Sjölejon were rebuilt during the 50th and the experiences from the salvage German 3503 were used. Snorkel device, hydraulic steering and others. These rebuilding were made at Kockums, Eriksberg Mechanical works and Stockholm Navy yard.

Already 1959-60 the boats were decommissioned, after only 5 years been updated. Probably this decision was a political one in order to reduce the Swedish defense

These names were used again when 5 new boats were produced 1965-68 except Sjöborren. 1992-94 Sjöhunden and Sjölejonet were life time prolonged. These boats, built during the first part of 40th and equipped with the old pressure type of hull, still was left, for an active time up to 2000.

Page 10


Swedish version


U1 - U3

Rebuild to coast U-Sub 1949 and 1963
U4 Forellen
U5 Abborren
U6 Siken
U7 Gäddan
U8 Laxen
U9 Makrillen

Mine layers 1943

Info coast submarines U1 - U9. Ref 1
Info coast submarines U1 - U9. Ref 1Info submarine Näcken type. Ref 1
Info submarine Näcken type. Ref 1Najaden. Ref 1
Najaden. Ref 1Coast submarine MAN-diesel. Note 4 valves and pushrods. Ref 1
Coast submarine MAN-diesel. Note 4 valves and pushrods. Ref 1Coast U-sub U3:s torpedo room. Ref 1
Coast U-sub U3:s torpedo room. Ref 1Telephone boye to be used in emergancy. Ref 1
Telephone boye to be used in emergancy. Ref 1




Coast submarine U1 - U9. Ref 1
Coast submarine U1 - U9. Ref 1

There were very large resources to build submarines during WWII. Swedish defense and and Parliament understood that for Swedish defense submarines were the best alternative contrary to normal warships. Furthermore submarines were cheaper to produce than large armored vessels and cruisers as Sweden also was provided with.

The solution with submarines were of course an economic benefit which parliament thought was good.

The maximum plan of displacement pro boat could now be achieved. It was at 500 tons. But no one knew that those boats which would come in the 60 th reached 1000 tons and over. But in this case it was not about diver boats and instead real submarines. But could those large boats really act in the narrow Baltic Sea?

New technology had showed. It was welding. A riveted boat was much more sensible for pressure impulses. Welding was on the way to change this. Sweden was one of the first countries to to change for welding. A revited armored car when hit, the rivets were like rifle bullets. Now it became possible to open a submarine hull, which later was done several times when rebuilding.
Engine housings were normally casted and when such was cracked there were no possibility to change to a new one. The main submarine opening could not take a new housing.

Now the ministry wanted a new type. The coast ships. They were not supposed to act in the open sea. They should act around islands were they could get protection. This was primary on the Swedish east coast.

This type was constructed by marine office and got a displacement of 367 tons. Three bow torpedo tubes and one rear outside mounted torpedo. Furthermore one 20 mm air canon. this was kept on poop deck.

The ship was equipped with single hull and three pressure secure parts. Each had one gate for rescue. Engine arrangement  was 2 MAN-Kockums 8 cylinder, giving  950 ps at 6600 rpm each. Each shaft had one generator and electrical propeller engine.

For safety the ships were adapted to connect to a rescue unit. The new rescue ship Belos was aimed to act with this arrangement.

U1, U4-U7 were built at Kockums, U2, U3, U8 and U9 at Karlskrona Navy yard.

After the war an extensive rebuilding was done 1949 concerning U4-U9. At this opportunity the ships were named. U1 and U2 were decommissioned 1961 and U3 was reserved as a museum ship at Malmo Technical museum. 1963 another new update were done by 6 of the "number" boats. This rebuild meaning was that the boats were updated with varying equipment from the German submarine 3503, primary snorkel system.

The forced building of building submarines during the war gave also 3 mine laying torpedo boats. Neptun, Näcken och Najaden. These were based on the Delfin type and got 3 tubes in bow and 3 in rear. Delivered 1943. The displacement was increased to 550 tons. They were later changed in the middle of 1950 according to the same principle as the Sjölejonn. They were decommissioned 1960.

Coast submarine U3. Ref 1

See more pictures from submarine U3 in my website about Technical museum in Malmo.

Page 11


Swedish version

1954 - 58


Hunting U-subs
Hajen III


Hunting U-subs from the series U4-U9. Ref 1
Hunting U-subs from the series U4-U9. Ref 1 Spiggen info. Ref. 1
Spiggen info. Ref. 1


Salen II
Valen II
Bavern II
Illern II
Uttern II

Hajen III. Ref 1
Hajen III. Ref 1

Now we have reached the early years after war period, 1954 and forward. The salvage of the German high sea submarine 3503 was done. This ship was equipped with the latest submarine technology. No other country had the corresponding level.

The 3503 had a developed snorkel drive, rudder handled with hydraulic, everything in the boat were arranged to prevent sound to be transmitted and new shock damper devices for censors and sonar system. Surface speed 16 knots and sub surface 17 knots. The tonnage was 1621 tons and crew 54.

The best things were now to be used and built in for the update of the Swedish boats, old or new built. The names from the decommissioned boats were used again.

The first new named boats were the old hunting boats built in the 30th. They were revited so for that point of view there was no problem.

The 3503 equipment had been inbuilt on Draken. Primary the snorkel device. This made that Draken was decommissioned already 1948.

The first submarine with modern equipment was Hajen III. This boat was new built and launched 1954. Much technology was planned for Hajen III which not were built in. For example revolver torpedo magazine for reloading.

Hajen III got one extra update 1961 when a new rear end  was mounted. The boat also got a cross rudder and a large slow running propeller. This was probably manufactured at  AlcoPropeller Örebro and Österby Casting. Only producer in Sweden.

Hajen also got the new engine technology from S.E.M.T. Pielstick with V12 engines equipped with compressed air delivered. The engine gave about 830 hp. Further more the crankshaft was so constructed that it was able to be demount without turning the engine 180°.

Hajen class was decommissioned 1980-1984.

Page 12


Swedish version

1960 - 64


Delfinen II

Rebuild 1963
U4 Forellen
U5 Abborren
U6 Siken
U7 Gäddan
U8 Laxen
U9 Makrillen

Ombyggd Draken. Ref 1
Ombyggd Draken. Ref 1Draken. Ref 1
Draken. Ref 1
Info om U4 - U9, ombyggnad. Ref 1
Info om U4 - U9, ombyggnad. Ref 1


"Workhorse" Nordkaparen. Ref 1
"Workhorse" Nordkaparen. Ref 1

The marine ministry was very active in the beginning of 1960. They had three bigger projects running. A10/2 which was the Hajen. A11 were the Sjölejon class, A12 which was Draken Class and A13 which was Aborren. Now they had to co-ordinate all this.

Of all this one failure was to supply the Draken boats with the rotating magazine which was developed for homing torpedoes. It must have been plenty of place in the torpedo room!

A11 was delayed and the development of Hajen A10/2 was cancelled. A11 had in fact already taken form in the 50 th. Besides impulses from 3503 American  hull development had also been studied. These ideas were also used and they gave the boat higher speed sub merged than at surface level.

The principle to order component from Swedish companies, which the air force did during WWII. This meant that many Swedish companies were involved in this production. This was possible because of the new construction principle of 3 d construction, even if this was on a rudiment level. All this was handled by the marine project office, Naval Consult. Saab had at about the same time started with 3d construction.

There was also wishes to get a unity engine. Several companies worked on this problem.

Uddevalla yard and Flygmotor suggested an air independence system called Ulla 1. DeLaval and Kockums were for an atom machinery. Motala works constructed a system based on alcohol and oxygen. ASEA worked with fuel cells ammonia and oxygen.

None of these came so far that they became interesting for any actual boat. Nevertheless the developing companies had taken impression from abroad.

The only was Hedemora which presented their 12 cyl engine mount made of double 6 cyl. Se picture page 12.

The result was the old system with a battery boat, which became the solution for the project. Air independence system was not actual until some years after 2000.

When this was decided force was laid on the A12 project.

A new steering automation had been developed. The boat was in much a copy of Hajen III. Engines were 2 Pielstick with 830 ps each and a displacement of 770 tons. The revolver magazine for torpedoes was not built. Instead it became a half time update with new fire control, radar and snorkel.

Draken, Vargen, Nordkaparen and Springaren were ordered from Kockums. Gripen and Delfinen were from Karlskrona. These boats were decommissioned 1988-90 and were replaced by the county submarines.

Left of the projects were now A13. These were the old coast ships built 1943. They were highly needed to be updated. The line was to follow the Draken class. The rear end was replaced through cutting the boat just behind the engines and instead mount one Draken model with cross rudder and slow running propeller.

It was realized that the welding technology was so far ahead that it was possibly to do this without weakening the pressure hull.

The revolver magazine was now realized. It was mounted in the ballast tank no 3, just outside pressure hull rearwards. Shooting was done port side, but if the torpedoes were shot rear or front wards I don't know. The torpedo was named 411 and controlled by a wire. A complicated system, which together with the engines, were not changed and the boat didn't get any acceptable speed and running length, made that the uboats were decommissioned already 1972. All these different ideas are made that it is hard to follow the developement of this uboat type .

It was not any acceptable order until A11B was launched with the Sjöormen class.

At my visit at Maritim 2016 in Gothenburg where 2 museum boats are shown. The uboat Nordkaparen and destroyer Småland. It is hard to take photoes and get good overview pictures because the short distances to the objects. The pictures from the uboat are shown in the order I went through the uboat after I had crawled through the main opening on deck. Trial for explaining text is made. It is also shown that the armament must have been changed several times, compared with my earlier informations. Among these is the revolver magazine for torpedoes. This equipment should not has been in place. Originally there was also tubes mounted in the heck inside ballast tank 3 outside the pressure hull. As I earlier have written it there was no good function. On the destroyer the space was much better, but instead I had no knowledge of this destroyer. All pictures according to ref. 1.
Engine room place to control engines. Ref. 1
Engine room place to control engines. The most important were of course the two engines which were coupled to a generators. cont.
Engine control room. Ref. 1
The engine must charge in good order because of direct current. It means that certain rpm must be held. Note the number of fuses to the left.
Engine room. Ref. 1
One for me wellknow picture. This is an early Hedemora pre chamber V12 diesel in the 60° construction, from Pielstick licens, which was the last type from Hedemora. Note the tool box. The pushrods are on the lower side. cont.
Engine pipes. Ref. 1
The dirty white pipes to the left of valve cover are to take care a of cylinder pressure outlet. This is more clear in former picture. Red pipes are connections for varm coolant. cont.
Engine pipes. Ref. 1
Note the high pressure fuel pipe to the inlet diesel fuel valve. When this pipe burts serious fire often started. Later this pipe was made double. The red pipes are connections for cooling.
Toilet system. Ref. 1
The problem with a lavatory is to get rid of the feces. It is not emptied in the ordinary way. Instead a hand pump is used to move feces and water to a tank. Se info about handling below.
Cables. Ref. 1
In the toilet room you can see the current cables crossing a wall to the next part. It is an important construction as this part must be both pressure and water tight. cont.
Engine pipes cooler. Ref. 1
On this and next pictures is the cooler shown. The cooler works for both inlet air and water to cool engine. Each engine has one compressor. It deliver compressed air through the cooler to the cylinders. cont.
Engine pipes. Ref. 1
One pipe is placed in the center and works as a volume for compressed air (not seen). Connections are made to each cylinder. Later engines got a separate cooler for engine. The compressor connection can be seen on the top of cooler.cont.
Compressor outlet. Ref. 1
Below the compressor the flexible connection can be seen for the cooler. I am unsure if it is an screw or lamella compressor. cont.
Compressor for ilet air. Ref. 1
The compressor is activated by a direct current motor. This system was cancelled when exhaust turbo later was introduced.
Compressor coupling. Ref. 1
The picture show the compressor and electrical motor and the coupling. The screw model was a swedish development.
Kitchen. Ref. 1
Here the picture is taken facing the next room forwards. cont.
More kitchen. Ref. 1
This must be a part of kitchen. For a silor it has another name. cont.
How to cook food. Ref. 1
This is the way to cook food. The smell must have spread inside the whole boat area.
Through to the next room. Ref. 1
Here I have crawled through a room opening and look back. Note the two compressor tanks. Don't know the function.
Radio central. Ref. 1
This table is the central for radio?. I missed the microphone. But all may be sent by morse system.
Valve/control room. Ref. 1
A passage through room with lots of fluid valves. Note that all connections are flexible. The sailer working here must have knowledge to chose the right valve.
Controll room. Ref. 1
The same picture again. The big pipe in front is one for ventilation. A room for controller.
Diving board. Ref. 1
A table for diving control. The funnel to the right and left of the big instrument (depth?). It is a comunication pipe. May be it is the diving board.  A diving took 30 sek. Read text.
Diving table. Ref. 1
Here the comunication pipe is seen more clearly. To clarify read next picture. Note that there are no screens. It may be the diving board. Read text.
Diving board. Ref. 1
Diving board. Explanation for the this board. Here is explained about active and passive sonar. I have only text picture below of the steering board.
Hydrophone information. Ref. 1
This text explain about active and passive sonar. That was the way to find enemy. It is also called hydrophone. See next picture.
Hydrophone equipments. Ref. 1
This must be the hydrophone equipment. Read text former picture.
Steering room. Ref. 1
This room was not accessible. It was closed. It may be the steering room.
Steering room. Ref. 1
Info about steering room.
The activities of the uboat. Ref. 1
The activity of a uboat.
Resting place. Ref. 1
Resting place for crew. Normally they shared beds with others placed near their working place.
Work and reting combined place. Ref. 1
Working and resting place.
Info toilet system. Ref. 1
Info about the function of the toilet, with all it's valves.
Entering the torpedoe room. Ref. 1
Next opening seen forward.  Here you enter the torpedoe room. Not the bed pillars.
Looking bacwards. Ref. 1
Looking backwards from the side of former picture.
Torpedoe room. Ref. 1
Here you see the front bed pillar. Longer ahead the rear part of the rotating torpedoe magzine.
Storing torpedoes. Ref. 1 
The rotating magazine end and torpedoes ready to enter. Normally there were 8 torpedoes in the magazine and 4 in the tubes. Before this there were stored torpedoes.
 Battery area. Ref. 1
A close look at the battery area of the uboat.
 Info about torpedoes. Ref. 1
Information about how a torpedoe is constructed. Sorry its a bad photo and the text is hard to read.
 Info about torpedoes. Ref. 1
A slightly better photo about torpedoes.
 Torpedoe tubes. Ref. 1
Almost the same picture as next one. 4 torpedoes can be preloaded.
 Torpedoe tubes. Ref. 1
Ends of the torpedoe tubes. The torpedoe leave it with  help of compressed air.
Revolver magazine. Ref. 1 
Pcture of revolver magazine seen forward. Here there are 8 torpedoes stored. The function in the middle I don't know. May be something because of paint wear.
 Torpedoe tube. Ref. 1
A torpedoe tube is a complicated contruction.
 Inlet side of torpedoe tube. Ref. 1
One detailed picture of the 4 torpedoe tubes.
Torpedoe tube. Ref. 1
The torpedoe is equipped with gyro which gives it a straight running under water. Normally many of them where thread controlled and because of this easily hit the target.
 Torpedoe room. Ref. 1
One look forward beside a tube.
 Middle hole in revolver. Ref. 1
I have wondered what this thing is used for. May be someone else know. This is the middle hole in the revolver.
Torpedoe store. Ref. 1
Except the revolver magazine the uboat stored further torpedoes.
 Main opening. Ref. 1
The main opening to get inside the uboat. This opening restricted the largest part to take onboard.
 Telephone emergancy buoy. Ref. 1
A telephone buoy used only in a emergancy situation.
On deck. Ref. 1 
Two picturees seen from the front. The main opening is placed on the other side of tower. Note the telephone bouy.
 On deck. Ref. 1
Beside is the destroyer Småland placed. In order to go back on land you see the gangway behind.
In order to enter the sub you had first to go over to the destroyer and then step down a stair to the sub. Not shown..

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Swedish version






Info Sjöormen ship. Ref 1
Info Sjöormen ship. Ref 1The double Hedemora six on test at Hedemora works. Not that the picture show a standard engine. Ref 53
The double Hedemora six on test at Hedemora works. Not that the picture show a standard engine. Ref 53




Hedemora engines in Swedish submarines

Hedemora Disesel 2017-

Hedemora engine in mine destroyer


Sjöhästen. Class ormen from 1968. Ref 1
Sjöhästen. Class ormen from 1968. Ref 1

Now we have come to an interesting time for me considering submarine engines. As a consulting engineer I got an assignment at Hedemora Works which for a long time have had license for S.E.M.T. Pielstick engines.

Hedemora had been established by the Johnson concern 1945. They wanted an own  marine engine manufacturer for their merchant ships.

This was developed in the beginning of 1950. The meaning was to develop and produce the V-type Pielstick type engines and this continued for a long time. The engines were a license production from S.E.M.T. in France. Very common was that this type of engine was sold as electrical aggregate for tugs and on drilling platforms in the North Sea. They were also sold as stationary reserve power.

The engines from Hedemora are pre chamber diesels. These types have a lower sound level. Today they are not sold because of higher fuel consumptions. On the other hand they have a construction which suit some military needs. Like sound level and a crankshaft construction, good for submarines.

The engine housing of Hedemora were fully welded which made them tougher and also possible to be repaired inside a submarine hull. The second advantage was that the housing could be welded by thicker plates and in that way be less sensitive for vibrations. This gave a noticeable lower level than casted housing. The third advantage was that the crankshaft construction made it possible to demount it without turning the engine around.

In this I entered with no experiences of this kind of engine. I was only supposed to make drawings. The first mission I got from my boss Jan-Erik Falck was to clean up some rests from the double six engines which Hedemora had developed for the Swedish Sjölejon class submarines. This became of the unity project for engines. The engine type was a Hedemora idea.

Two V6 units were mounted together with a gearbox in middle of the engine. In front another gearbox from which sub aggregates got it's power and in front the cooling system was mounted. On the rear a generator was mounted. This was a god idea but as all medicals have, there were also disadvantages. The housing of the Pielstick engine was changed and built up with much thicker steel plates. This gave a heavy more vibration-less housing with higher damping of the acoustic velocity in the material. This housing was further mounted on rubber parts in the submarine hull. One new cylinder head was constructed by Jan-Erik Falck and also a more good looking cylinder head cover. These were options for all type of A-engines.

The engine was started with a compressed air driven start-motor. One exhaust driven ABB turbines manufactured in Switzerland for each double unit. All exhaust left the engine inside the V in order to power the turbines. Every cylinder had it's own fuel pump activated by a nock on the camshaft. This was ok as long as the high pressure pipe not broke. If it did fire could break out. This could be the most dangerous incident to happen inside an engine room.

But of all disadvantages for Hedemora engines were less than other options. Of this reason several submarine types were equipped with this engine. I tell you more about Pielstick system bellow.

The Sjöormen class were now built with conventional diesel electric machinery. The battery pack was enlarge and a function to pump the electrolyte liquid around the batteries. This gave a more even electrolyte mixture. All this gave the sub an action time which was better than all earlier ships.

The pressure hull was changed into 2 parts and an inbuilt escape airlock in the tower center. By a new calculation principle, it was possible together with other more local steps, allow the sub to resist higher blast waves. This was controlled through practical tests. One 100 kg depth bomb was exploded on a secrete distance and gave no damage of serious nature.

Weapons were 4 tubes for 53cm and 2 for 40 cm. They had different kind of firing system. Plunger or ejection.

The engines were standing on calculated rubber units in 45° from Trelleborg. The montage of these were done in open sections of the boat.  See picture below. Then the open parts of the boat were welded together. This was a building method which was tested earlier and it became updated for the next sub class.

The new type of cross rudder which had been introduced gave the boat an extraordinary operation ability. This system was introduced since several years on Swedish boats. Only problem was that in surface half of the propeller was working over water level. This was the cause that the ship got a higher speed submerged.

A developed automate which worked hydraulic spared a few of the crew. Compare Draken with 37  in crew now only 27 were needed. Note that the German 3503 had a crew of 54.

The proof of good silent running was shown, when during trials in England the Royal Navy could not detect the boat on one test length. The English were irritated over why the test boat didn't moved the supposed length. The Swedish boat had to "help" them. This was of course a secrete.

Kockums build the three, Sjöormen, Sjölejonet and Sjöhunden, while Karlskrona got Sjöhästen and Sjöbjörnen.

Now these were successful constructions worked on the field for 10 years before a update were done. The computerized development in this time went very fast and those component became old quickly. Early 1980 the snorkel system and shooting system SESUB were changed together with a new type of torpedo 613. One can have the feeling that the snorkel system must have reach the end of development, when every boat had got at new system since beginning of 1950.

But for a good construction it is easy to make it even better and this was the fact.

New boats were supposed to be build 1992, but the ministry were sufficient and from the class 2 were only 2 lifetime prolonged. Sjölejonet and Sjöhunden were chosen. They got some new components and the diesel engines were changed for 4 Scania Vabis rebuilt truck engines. Small engine advantage were search for. In the long run it is said to be a good solution, but never reused. I think that it was chosen because of the lower price compared to new Hedemora diesels. Direct current generators were chosen instead of alternating current. The hope was that the boats could work up to 2000. I don't know how they solved the drive system to generators and the coupling to the snorkel system.

Now it had been peace for a long time in the neighbourhood the backlash came. The Swedish Parliament decided to reduce the submarine weapon by 5 units. It must have been hard to be an enthusiast in the ministry and navy. 5 ships were sold to Singapore 1997.

Sweden wished very much keep there so called welfare. But to create it one must have a free country.


Mounting of  Hedemora "Double 6". Note generator angled 4܄5 °. Foto from  Marinmuseum. Ref 1
The engine is not yet mounted on it's sound and vibrations retarding rubber bedplate. Note what you see of the housing is the "rusty" scale of the pressure hull. Outside this is then the forming hull built. Note also that the generator is turned 45° to be able to push the unit inside the hull.

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Swedish version





Info Näcken class. Ref 1
Info Näcken class. Ref 1Updated Näcken. Ref 1
Updated Näcken. Ref 1Old  Näcken class 1978-79. Ref 1
Old Näcken class 1978-79. Ref 1U-sub  Näcken 1988. Ref 1
U-sub Näcken 1988. Ref 1



Transport of Neptun to museum place

Below som pictures of Neptun in the new Submarine hall.

Kön för att gå in i ubåten. Det tog 1/2 timme. Ref. 1
Queue to enter inside Näcken. It took 30 minutes. Ref. 1
Näckens propeller. Ref. 1
The prop for Näcken. Ref. 1
A torpedoe store room in the rar of boat. Ref. 1
A torpedoe store room in the rear of boat. Ref. 1
Action room. Ref. 1
Action room. Ref. 1
Operation central with periscope. Ref. 1
Action room witt the periscope. Ref. 1
Detta var vad som kunde ses av en motor. Om det är V16 eller Scania Vabis vet jag ej. Ref. 1
This is what could bee seen of an engine. If it was the V16 or Scania I don't know. Ref. 1

U-sub Näcken 1988. Ref 53
U-sub Näcken 1988. Ref 53

Marine ministry showed it's changeability when planning for the Näcken class boats. This was project A14. Since earlier it had been much talk about a Sterling engine, but it was many years left before it could be serious used.

It was hard day for Hedemora when the decision was known. Much work had been laid on the unit class engine and it was hard to lose in favor of a single V16 engine from MTU in Germany.

It was just like when Norway turned down JAS and instead bought the much more expensive fighter F35 from USA. This plane is not yet 2014 ready from the drawing table.

Great excitement at the selling group in Hedemora. An appeal against this was sent to the defense minister. Conferences and so on. But no result. The decision stand firm.

This sub got one MTU V16 giving 2100 ps and a test prototype of Sterling engine for complement to the V16. Furthermore one smaller truck diesel for extra charging in emergency.

The sub could now reach a speed of 20 knots under water. A much more effective automation and also a central computer handled most of normal activations. Speed in surface position was only 10 knots depending of the cross rudder. This was because of the propeller was half above water. Normally the boat moved with only a part of tower over water.

All of the best constructions were used and copied from the Sjöormen class. Just as the pressure hull which was divided into two parts including an emergency opening.

The engine compartment was planed to be unchecked, but later this showed not to be possible. The torpedo system got new types of tubes and a system where that the torpedoes swam out.

The hull was divided in production sections and these where separate manufactured at Kockums and Karlskrona. All parts were welded together at Kockums. 3 boats were ordered.

1988 a rebuilding with a complete Sterling unit. The boat was cut beteen the MTU diesel and the electro central. Here a 8 m long, complete Stirling unit was welded. Displacement increased with 250 tons till totally 1218 tons and a total length of 58 m. The goal during 1940 was 500 tons. The Stirling engine was in the first hand aimed to charge batteries, or for low speed sub surface (3 knots) and diesel engines for charging and surface of water.

It was the sister submarine Neptun which prevented a Russian high sea tug to rescue U137. The chief of the submarine was Björn Hamilton. later U137 was escorted to the territorial border in order to be turned over to Admiral Kalinin.

An interesting notice is when U137 sailed out into international water was that the exhaust went out in the rear end, not in the tower. What this means according snorkel and so on are possible to be speculated. These Russian submarines were of an old type.

The Näcken sub was 2001 sold to Denmark and got the name Kronborg. 2014 one can see in paper notes that it is on her way back to Sweden. Neptun and Najaden were decommissioned 1998.

Näcken was rented/sold to the Dänish navy with the pledge to be rebought after a certain time. The sub was equipped with the latest stirling arrangment which was mounted in an 8 m long part of the hull.  The same update hade been done with some other subs. The Näcken class was decommissioned  already 1998, why one can assume that they didn't were lucky constructions. One can on the few pictures I succeeded to take suppose that it was wery narrow inside.

Comparing with Södermanland and Östergötland which yet 2007 are in action. These class, the county subs, also got the new stirling units update with 12 m long part in the hull.  Hälsingland and Västergötland were sold to Singapore. If they got new engines and stirling units I don't know.

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Swedish version






Info Landskapbåtarna. Ref 1
Info for "County sub". Ref 1Ubåt Södemanland. Ref 1
Uboat Södemanland. Ref 1V12A15UB. Ref 1
V12A15UB. Ref 1Ramlager upphängning. Ref 53
Main bearing. Ref 53Top head Hedemora Diesel. Ref 53
Top head Hedemora Diesel. Ref 53

Utrustning för att förspänna centrera lagerhållaren. Ref 53
Equipment to mount main bearing holder. Ref 53 Montering av vevaxelupphängning. Ref 53
Mounting crankshaft bearing holder. Ref 53








Södermanland. Ref 1
Södermanland. Ref 1

Now we have come to the submarine class I like best. Most because I have drawn much of the engine adaption. It took me more than a year to accomplish.

It was mainly for this purpose Hedemora had search consulting support 1986 as help for Jan-Erik Falck. The housing was constructed by a engineer from Gothenburg.

I had just got the first construction computer including a program which worked on the basis of number commandos. This controlled the way of drawing. After some months I was quite quick to act 2 digits and a return for these actions. This computer had a hard disk with only 5 mb. This was supposed to be enough at this time. I worked and worked and suddenly I had filled this disk.

For plotting on paper I used ink pens with different thicknesses. This was very troublesome because the plotter didn't felt when a pencil was clogged. At last I had to divide the drawing in several parts. I felt like a pioneer. This continued till I got a digital plotter.

Really serious computer construction couldn't be done until IBM announced their new computer equipped with one of the first Microsoft Operating system. The program ware was Acad 2.5. This was of course a simple 2 d system, but it was possible to make drawings.

Every single detail must be drawn digital and then the assembly drawing separate. This took time. It was a terrible work. At this time there was no useful 3d system. Computer Vision had one but the computers were not powerful enough. I saw at Adtranz how difficult it was.

Picture of the crankshaft bearings. This consist of 4 parts. 2 central parts which carry the bearing parts. Compression device which hold the bearing part and the layer unit, with a specific pressure. See picture. The outer and inner parts are placed with the help of pins. This is a genius construction. But if to high rpm or power was taken from the engine this type of bearing system could not carry the crankshaft forces. Vibrations destroyed the fit.

The cylinder head. This head was an updated version by Jan-Erik Falck for the Sjöormen class.

Engine housing. The picture shows that it consist of one unit contrary normal engines which are divided over center of crankshaft. If an engine crash happens with for example bearing break down, the plates could be defect. They were in that case able to mend. A cast housing had to be fully changed.

It is amusing to look at such a naked housing. I know every single plate as I have drawn them in three different variants. Later I drew the same housing for V12B, V18B and even for the Australian Ran 471 in 3d.
----------------------------------------------The new thing with the Hedemora V12A with 1100 ps each equipped sub, was that it was supported by a prototype Sterling unit. Old submarine captains and crew members were very pleased with Hedemora engines. There were also ideas with small engine arrangements. This had been tested on the Näcken class. It is said that no problems with exhaust and snorkel working are noted.

Any such arrangement was not installed and not in the future either. But the next class A19 Gotland a small diesel to take care of emergency charging. It was placed far back in the propeller room.

Exhaust over snorkel was wanted but had a negative influence on engine power. This was solved through pre compressed inlet air to the turbo chargers. Test were made on Sjöormen with sufficient result and at the same time with higher effect.

The submarine hull was manufactured by toughened high strength steel. This made that the displacement could be kept low. Comparing that the Näcken subs were manufactured by close grained steel.

In the emergency opening it was possible to escape from the depth of 200 m.

Torpedo tubes were arranged into 2 rows and 6 + 4 tubes. Because of the battery units had been constructed low, it was good place in the torpedo room. All types of revolver torpedoes system and also rear en placements were abolished. It is curious with all these types of different solutions on every boat class.

According snorkel system, it has large influence on the hearing of the crew. Every time the snorkel device close for water, the exhaust turbines have to take in air from the volume of the boat. This lower the atmosphere pressure and of this reason change the tympanic membrane. Head ache must be very usual when using snorkel and rolling sea. A noticeable thing was that crew had extra payment when snorkel diving.

Södermanland and Östergötland were rebuilt and got a Sterling section of 12 m mounted. Displacement increased till 1500 tons and length to 60.5 m. A second rebuilding was done 2003 was so extensive that they were classed as New Södermanland and Östergötland. Both are still in use. Hälsingland and Västergötland were sold to Singapore 2005 and delivered 2012.

Page 16


Swedish version

1954, 1990


Info Spiggen 1954. bought in England 1958. Ref 1
Info Spiggen 1954. bought in England 1958. Ref 1 Info "Spiggen" built in Sweden 1990. Ref 1
Info "Spiggen" built in Sweden 1990. Ref 1 English Spiggen 1954 on Gota channel. Ref 48
English Spiggen 1954 on Gota channel. Ref 48 English Spiggen 1954 in Swedish lake. Ref 48
English Spiggen 1954 in Swedish lake. Ref 48 Mini U-sub from WWII at  Motor Technica museum Germany. Ref 1
Mini U-sub from WWII at Motor Technica museum Germany. Ref 1


Spiggen 1954

New minisub 2013

Spiggen placed in Töre

Spiggen build in Sweden 1990. Ref 1
Spiggen build in Sweden 1990. Ref 1

Spiggen 1954 was a test boat within the Swedish marine. It was a boat from England and had the name XE Stickleback. This type was used in Sweden to transport attack divers. It was developed during WWII and acted to defeat the German battleship Tirpitz. It was partly heavy injured by one of this mini sub. Later Tirpits was sunk in a most spectacular way. Bombs were drop into the water outside Tirpitz and the ship rolled around and sunk.

Spiggen 1954 was presented back to England as they had not reserved any for the future. The rests on the picture below is probably one saved from the Norwegian fjord where Tirpitz was defeated.

1990 Sweden built a slight larger model during the assumed submarine violations on Hårsfjärden. It was used as a goal for training. It was 11 m long and with a weight of 12 ton and room for 4 persons. It was powered by one diesel engine. This boat was spared  for reserve in beginning of 2000 and is waiting to be enough historical interesting to get a place at Marin museum Karlskrona. Today 2017 it is moved to Kalix/Töre.

Last picture to the left. When I visited Motor Tecnhica in Germany, I saw this mini sub. It seems to be a real mini sub. I presume that when a torpedo is fired it must have left submerged as a balloon.

Spiggen 1954 presented back to England. In fron one original from a Nerwegian fjord. Ref. 48
Spiggen 1954 presented back to England. In front the rests of one original from a Norwegian loch. Ref. 48

Page 17


Swedish version





Info Gotland class. Ref 1
Info Gotland class. Ref 1 Uppland. Ref 1
Uppland. Ref 1 Gotland. Ref 1
Gotland. Ref 1


Ubat A19

HMS Gotland

HMS Halland

Uppdate of Gottland 2014


Halland. Ref 1
Halland. Ref 1

Now we reach the last submarine class built in Sweden.
It is true that a project  is on the way for a new class named Viking 2014. But it is unsure when Kockums have been merged with HDW yard in Germany. They don't want any concurrent submarine yard.
Note this has probably been solved when Saab bought the yard from HDW 2014 for Viking.

The development is called A19 and the class type got the name Gotland.

By some reason the Marine ministry wanted to changed engine deliver again. Now they prefered MTU again. They chose 2 V16 diesels pro boat. These engines gave 2980 hk and the known reason was the low sound levels. Hedemora thought that their price was to high for the proposed developed engine. I thought that the crankshaft system together with higher rpm was the cause. Furthermore there was the same engine earlier in Näcken and also for the Swedish coast corvettes. This was the death for Hedemora and the firm stopped their new production and started to only deliver spare parts for old marine machinery. Hedemora also offered other types of engines, like Isotta Frashini.

The Stirling machinery was still only a test complement. It could only deliver charge for 3 submerged knots. For quick charging and surfaced the diesel was the leader and will be for long time.

Great efforts was made to minimize all different signatures of the sub. For ex. sound and magnetic signature.

A new developed computer system was introduced and all system were programmed in ADA. This was supposed to be used in the future. This decision was faulty as program systems develop and have difficulties to speak internally. Compare cad programs which can't work with each other.

As many as 9 torpedo tubes were built in the bow. There are possible to fire several cable controlled torpedoes. Of these, there are 2 dimensions.

This class is equipped with the latest development of Sterling machinery. This gave the boat a length of 60,4 m and a displacement of 1490 tons.
Compare the German high sea boat 3503 which had the length of 76.7 and a displacement of 1621 tons. According to the definition it is the mass of water boat when floating.

Now much better figures were reached compared to the Södemanland class to keep itself hidden under water. The crew was the same as for Södermanland, 25. But it was a large boat in the small Baltic Sea.

The boat was equipped with both active and passive sonar system. The main difference is that active is easy to locate. The system gives a 3d picture on a computer screen, showing the surroundings. It is just like to sit in a car driving. May be not quite so far, but in this direction.

A new system for battle and shooting similator system were developed so the crew could train with this on land. It was just like what Swedish pilots work with. This program was not ready until all three boats were launched. Another simulator type were produced through examination works.

Gotland class is still 2014 in use for Swedish marine. A new type, A26 submarine is projected in cooperation? with Danish Marine.

Page 18


Swedish version



Hedemora Diesel

Welding of the house. Ref 53
Welding of the house. Ref 53UB house when machining. Ref 53
UB house when machining. Ref 53Cooling system mounted on engine front. Ref 1
Cooling system mounted on engine front. Ref 1Center unit for crankshaft. Ref 53
Center bearing unit for crankshaft. Ref 53Cylinder unit with piston. Ref 53
Cylinder unit with piston. Ref 53Cylinder head for sub class Sjöormen and Södermanland. Ref 53
Cylinder head for sub class Sjöormen and Södermanland. Ref 53Pushrods for V12AUB. Ref 1
Pushrods for V12AUB. Ref 1Controlling drawings. Ref 1
Controlling drawings. Ref 1
Visit from marine ministry. Ref 53
Visit from marine ministry. Ref 53Equipment for mounting bearings and cranksaft. Ref 53
Equipment for mounting bearings and cranksaft. Ref 53
Thank you after end of job. Ref 1
Thank you after end of job. Ref 1

Delivery ready Hedemora V12A UB. Ref 1
Delivery ready Hedemora V12A UB. Ref 1

The best mission I have had in my working life was the development of the Hedemora V12AUB diesel.

This started in the beginning of 1986. I showed up at their small construction office slight nervous for the complete new surrounding.

I and Kalevi Broman should cooperate working with detail drawings. The firm where I was employed was, Kontima Consulting AB. This firm had put much money in modern drawing system. The first was a Dutch system with the name Kuhlman. It was sold by Spacio in Malmö. It showed that it would not be sufficient enough. We changed to Auto Cad version 2.6, the second Acad update. This was good for the need and I followed all versions up to Autodesk Inventor 8. Several times computers were updated to more powerful units. This was sold by System development in Linköping.

It is easy to state the fact that this work could not be done without a computerized system. The time to accomplish this mission was reduced radically.

The lead at Hedemora saw that the result from me was so good that they also bought equipment for Kalevi Broman. I became his teacher and how to manage it. He was long time after this very thankful and often said that if not he had gone for pension much earlier.

It took of course several months before I had put in knowledge of the construction of the engine.

During my time at Hedemora which lasted for 9 years I worked under 3 managers. One disappeared voluntary withdrawal. Next because of lost of a submarine engine order, when Marine ministry chose another engine (A19). The third was left when I withdraw.

Once I followed to the Muskö base and visited the storing area for spare parts. Very interesting. Here Swedish marine had complete store of spare parts for submarines. Among all we looked at camshafts. The base is decommissioned, but it is not able to withdraw from such a big atom secure area. Falk and I was also on several visits by air transports. We flew from Borlänge.

When the work had come so far that delivery test were running I voluntary sat in the testing room. Here we had one ABC computer which should simulate snorkel running. This type test was already done with the double six engines. It worked in the way that a valve closed the exhaust pipe during a specific time. What happened was that he engine almost stopped and when open again increased rpm by a notable explosion.

The pictures from above.
1. Housing when welding
2. The housing painted and marked, put on a machinery table at Hedemora Works.
3. The housing mounted. The picture show the front end with cooling system. It was two system a) cooling the engine by cooling water and by salt water. The two tubes indicate this.
4. The important part that keep the bearings and crankshaft in place. It was mounted with hydraulic and a specific pressure. In the center were the pressure lubricated bearings.
5. One complete cylinder unit with piston and bolts.
6. Complete cylinder head including valves for change. No 5 and 6 are showing engine service including pison and connecting rod. This make the engine very serviceable.
7. The push rods with the connecting casted cover pipes. It was mounted just over the camshaft.
8. Two of the boys studying the assembly works drawings. They have built and test run lots of Hedemora diesel engines. In fact they didn't need to study drawings.
9. Visit from the Marine ministry (black costume), customer 3 from left, engine consult from Stockholm, representative from Hedemora 4 from left.
10. Demo picture how to mount crankshaft bearing.
11. Info which followed the large upper picture. Withdrawn.
12. With this kind message my first session ended at Hedemora.

Large picture above.
The engine unit ready for delivery. Totally 8 units were made (4 submarines) giving 1100 ps each. I have not heard that any new engine was manufactured as exchange.

Bottom large picture.
The engine mounted on test bed with connected pressure and temperature indicators connected. The large pipe on the engine side is casted in silumin at Kolsva casting works. It handle the compressed intake air from the 2 ABB exhaust turbines. It was some difficulties to adopt them according inlet hole contra exhaust. The exhaust outlets were on the side of top head.

Over the valve cover you can see the bent high pressure fuel pipe. The fuel was pressed by separate pumps. The pipe is bent in two 90° angles. It has one inner main pipe and one out security pipe. The outer prevents the oil to flow over the engine when inner pipe burst.

One read in records for accidents among boats with Hedemora diesels there are among Sjöormen boats 4 accidents with this high pressure pipe. Södermanland class has no indication.

V12AUB during delivery test. Ref 53

Submarine engine on test bed with attached pressure and temperature transmitters connected. Note the vibration rubbers ordered from Trelleborg, mounted in 45°.

Page 19


Swedish version

Motor V18BUB


Australian admiral

Collin Class sub

Collins Type 471

Hedemora Diesel Sub mountings

Kockums 471

Ran 471 during delivery test. Ref 53
Ran 471 during delivery test. Ref 53
V18B 471. Mounte on testbed for control of service area.  Ref 53
V18B 471. Mounte on testbed for control of service area. Ref 53Demo how crankshaft is mounted. Ref 53
Demo how crankshaft is mounted. Ref 53Demo changing cylkinder unit. Ref 53
Demo changing cylkinder unit. Ref 53Maching houseing for a standard engine. Ref 53
Maching houseing for a standard engine. Ref 53Mounting device for crankshaft center. Ref 53
Mounting device for crankshaft bearin center. Ref 53Cross view of Ran 471.  Ref 53
Cross view of Ran 471. Ref 53A good way to be out of work. In this case from manager Jan Blomquist. Ref 1
A good way to be out of work. In this case from manager Jan Blomquist. Ref 1

Delivery test in Hedemora. Ref 53
Delivery test in Hedemora. Ref 53

It became a short break for me between A12 and Ran 471. But as fast as this business was settled I had to stop my job and go back to Hedemora.

Now it was the same mission as with A17, to produce one adoption construction of the standard engine V18B. B means an engine according the Pielstick system but with lager cylinder volume than the A engine. The B engine in UB version gave 1900 ps.

Apparently this was a much larger mission for Hedemora that the earlier engine V12AUB.

For this work there were much less support from standard engine which could be used.

But as usual it was the housing itself which should be updated to Ran specification.

All of a sudden one barrack was built up on the courtyard outside the works with 8 rooms. Here I and Kalevi Broman moved in with our computers. Also another 3 constructors/drawers were hired, all with knowledge in cad writing. Furthermore there were people with other works like description, planning and management. The management was not so much seen because he shared this job with his own firm. Jan-Erik Falck handled the correspondence with Australia. I came according to him in the background. But we had many pleasant talks after work when I really should go home.

The manager director which now was in lead  was Jan O Blomquist who knew how to bring the best work result from us. According a mail he only sat and looked, filled with wonder how work was running.

Hedemora delivered 3 engines. This was what one submarine should be equipped with. This was for the first boat that Kockums manufactured. The other 5 were supposed to be produced in Australia. The idea was that a complete new yard was to be started for this and future production. There was not any similar industry in the country. Compared to Kockums which had produced submarines since 1904.

What we in Hedemora got to know was that they had great problems to keep delivery times and to get qualified people. One reason for these delays were the union system. Each kind of working type had their sub union. It had to be an agreement for every part of work. Minor strikes and notifications were common against the logistic of the work.

If you were a welder, they were not allowed to use tools to fasten a screw for example. This is not common in Sweden. If necessary you can make your job easy.

Another story which went around, but might not be quite thrue was the following. Instructions should be present for everything. If oil would be emptied, instruction said that a bucket had to be hinged under. This must of course be understood. 

It is possibly to read on internet that some welds were not burned through in the pressure part of housing. The control function in Australia wanted all welding to be burned through. This was not a habit for Kockums.

It was two different industrial ideologies which met. Perhaps it was not so curious that the production in Australia had problems. Hope that they have solved most of them. It was problems with the fuel tanks which were filled with salt water. Some of this water followed into the fuel pumps and destroyed them. Probably it was such things and other handling behaviors that caused problems.

Pictures from above to the left.
First engine on test bed. When starting an impressing sound was heard, when the 18 cylinders immediately run up in rpm.
Two engines mounted together with space as supposed in the submarine. As closed as this, no engine had been mounted in Swedish boats. large problems must be actual when shifting cylinder units and cylinder heads. See pictures.
Demonstration how a crankshaft was mounted. In the submarine it must be free area in rear for the crankshaft. This work is much less compared to dismantle other type of engines, turned up side down.
Demonstration how to change cylinder unit.
One housing for V18B during machinery. Note that this picture shows a standard housing. You can note this when looking at the horizontal mounting feet. They are supposed to be in 45° angle.
Demonstration how the crankshaft layer system are mounted.
Bild 7.
Cross section of the Collins type submarine.
With this notice my job had reached the end.
Large picture above.
The engine on test bed. Note the prolonged mounting feet and vibration elements.

Page 20


Swedish version

Industrial standard engine


Hedemora Diesel 2017

Offshore engines

Hedemora V18B industrial engine during test for high sea tug. Ref 53
Hedemora V18B industrial engine during test for high sea tug. Ref 53Test for all Hedemora engines mounted in high sea boats. Even  Ran 471. Ref 53
Test for all Hedemora engines mounted in high sea boats. Even Ran 471. Ref 53Montage for connecting rod and piston. Ref 53
Montage for connecting rod and piston. Ref 53Changing cylinder unit. Ref 53
Changing cylinder unit. Ref 53Mounting of piston unit + connecting rod. Ref 53
Mounting of piston unit + connecting rod. Ref 53Mounting of cylinder head. Ref 53
Mounting of cylinder head. Ref 53Equipment for monting the layer sections. Ref 53
Equipment for monting the layer sections. Ref 53

Hedemora industrial engine V18B mounted in front of generator. Ref 1
Hedemora industrial engine V18B mounted in front of generator. Ref 1

I don't quite remember but it went till 1998, when I got the mission to draw weld and machine drawings for V18B and V12B.

Hedemora had sold these types to ABB and they were supposed to be mounted in oil platform/high sea tug.

That's why they were tested in angled positions, both horizontal an vertical according to pictures.

The mounting of the engine was done with horizontal feet. Picture above shows this mounting on test bed. The feet are not shown.

It became lots of drawings as I had to draw all parts both welding and detail drawings in 3d before the assemblies were built up. It became a great many drawings. These were partly in several versions, details, welding drawings, machined welding drawings, drawings with dimensions and the same machined after welding.

I made this job with great enthusiasm. It was made on distance as I could not be free from my ordinary work at Wirsbo Bruk. All was made after ordinary job in the evening and on Saturdays and Sundays. 

I later noted that depending on this extra work I got the mission to construct a complete production line for Inpex pipes. They were ready mounted in the line including couplings.

Sorry to say it showed that Hedemora had counted that this job was going to be ready in a too short time. Of this reason I had to deliver drawings partly.

This is very dangerous when changes in a construction like this often happens. This influence assembly 3d drawings and can cause them to be redrawn. In a 2d drawing it is only to change the measure.

Jan-Erik Falck became dissatisfied. Maybe because he was pressed by AWETEK in Avesta.

But the most disappointed wish was that I should integrate the 2d drawings from Broman into my 3d drawings.

This is impossible as I in such a way had to redraw them into 3d. I was forced to continue in my way. This dissatisfaction made me very sorry.

I consoled myself that the earlier mission for V12AUB housing had taken 9 months but I was ready after 4.

With this work I was ready with Hedemora. I didn't got any "Thank you" note this time. Before my pension I carried through 2 larger missions at Wirsbo Factories.
Inpex automation line and a complete installation with surrounding devices for a new press at Wirsbo forgings.

Pictures to the left from above.
High sea tug engine test.
Same as no 1.
Montage of piston and connecting rod.
Same as no 3.
Same as no 3.
Montage of cylinder head.
Demonstration how the crankshaft layer system are mounted..
Large picture above.
Foundation for electricity for ex. at a hospital.

Engine room on a oil plattform or cargo ship with V18B. Ref 1
Engine room on a oil platform. The engines are coupled to their generator. This might also be a picture from a cargo ship. Another 2 engines to the right totally 6.Pictures from different standard generator aggregates, from different years. Buyer of these engines were nuclear power works, oil platforms, cargo ships, high sea tugs, railway locomotives, hospitals, factories and others.

V6-aggregate. Ref 53

V6 aggregate. Ref 53

V8A aggregate. Ref 53

V8 aggregate. Ref 53

Early V10 SEMT Pielstick. Ref 53

V12A aggregate. Ref 53
Early Hedemora Pielstick unit. Note gearbox and turbo charger

Standard V12A for submarine Sjöormen. Ref 53
Double six cylinder engine.

V12A aggregate. Ref 53

Here a picture from a V16A delivered at railway engine. 100 copies were delivered to Turkey.

Complete V18B aggregate for delivery. Ref 53
Delivery of a standard V18B unit.

Electrical power central V18B iin underground cavity. Ref 53
V18B unit.

Oile platform. Possible Ekofisk. Ref 53

Office part for Hedemora Diesel. Ref 53

Section through the engine. Ref 53

Hedemora logo. Ref 53.

Page 21


Swedish version





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Pictures from the following owners have been used in
bjorns-story.se with the necessary agreements:

Reference 1: © Björn Bellander   bjorn.bellander(at)telia.com
Reference 48: Picture from website
Reference 49: ©Picture from Wikipedia

Reference 53: ©Agreements from Hedemora Diesel

Facts for this site has been : 3503 Dokumentation, From Hajen 1904 to Hajen 1954, The Swedish submarines 1904-2004, Hitlers ubmarine war part 5. Most picture my own Ref. 1.
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This site handles Swedish submarines. 19 pages.