E-boat

E-boat was the Western Allies' designation for the fast attack craft (German: Schnellboot, or S-Boot, meaning "fast boat"; plural Schnellboote) of the Kriegsmarine during World War II; E-boat could refer to a patrol craft from an armed motorboat to a large Torpedoboot. The name of E-boats was a British designation using the letter E for Enemy.

The main wartime production boats, from S26 onwards (but often designated the S100 class), were very seaworthy, heavily armed and capable of sustaining 43.5 kn, briefly accelerating to 48 kn. These were armed with torpedoes and Flak guns; commonly one 37 mm at the stern, one 20 mm at the bow with a twin mount amidships, plus machine guns. Armament varied and some S26 class boats substituted a 40mm Bofors or, less commonly, a 20mm flakvierling (quadruple mount) for the aft 37mm cannon.

The S26 class boats - which provided the bulk of the wartime deliveries - were 34.94 m long and 5.38 m in beam. Their diesel engines provided a range of 700 to(-), substantially greater than the gasoline-fueled American PT boats and British motor torpedo boats (MTBs).

As a result of early war experience of combat against the fast and powerful S-boats, the Royal Navy created its MGB force and later developed better-matched MTBs, using the Fairmile 'D' hull design.

Development
This design was chosen because the theatre of operations of such boats was expected to be the North Sea, English Channel and the Western Approaches. The requirement for good performance in rough seas dictated the use of a round-bottomed displacement hull rather than the flat-bottomed planing hull that was more usual for small, high-speed boats. The shipbuilding company Lürssen at Vegesack, Bremen, overcame many of the disadvantages of such a hull and, with the private motor yacht Oheka II in 1926, produced a craft that was fast, strong and seaworthy. It was also extremely seaworthy and very light, being constructed of wooden planking over alloy frames. This attracted the interest of the Reichsmarine, which in November 1929 ordered a similar boat but fitted with two torpedo tubes. This became the S1, and was the basis for all subsequent E-boats.

After experimenting with the S1, the Germans made several improvements to the design. Small rudders added on either side of the main rudder could be angled outboard to 30 degrees, creating at high speed what is known as the Lürssen Effect. This drew in an "air pocket slightly behind the three propellers, increasing their efficiency, reducing the stern wave and keeping the boat at a nearly horizontal attitude". This was an important innovation as the horizontal attitude lifted the stern, allowing even greater speed, and the reduced stern wave made E-boats harder to see, especially at night.

The rounded wood planking hull helped reduce weight, and flattened at the stern area, the aft section area was reduced at high speeds, it allowed more hydrodynamic lift.

Layout
The internal layout of the E-boat remained the same for all types. Its length was generally divided by eight transverse bulkheads (made of 4mm steel below the waterline and slightly thinner light metal alloy above) into nine watertight compartments. From bow to stern, these were:
 * 1) Containing a trimming tank, the anchor chain storage locker, forward "head" (WC) and crew washroom;
 * 2) the accommodation for senior ratings (six bunks, including one in a separate curtained-off compartment for the coxswain);
 * 3) comprising the captain's cabin on the starboard side, and the radio room on the port side;
 * 4) the two forward fuel tanks (capacity 2 x 3,000 litres), one on either side of a centreline walkway, located directly below the bridge;
 * 5) the forward engineroom, housing the two wing engines, still with a central walkway between them;
 * 6) the second engineroom held the engine driving the central shaft, with a walkway on each side, flanked next to the hull by auxiliary machinery;
 * 7) the two largest of the fuel tanks (each of capacity 3,150 litres), again on either side of a central walkway, with a third (smaller) tank of 1,490 litres below the deck;
 * 8) the junior ratings' accommodation, with bunks for fourteen men, plus the galley and the stern "head"; the boat's magazine was also in this compartment;
 * 9) the two aft fuel tanks (capacity 2 x 2,000 litres) and rudder gear.

Note that the earliest (shorter) boats lacked the first transverse bulkhead, and thus the senior ratings' accommodation was included in the first watertight compartment.

Personnel
The earliest six boats had a crew of 12 men, but by the time of the S7 and S14 types (S7 to S25) the manning had increased to 18 men. The S26 class required a complement of between 21 and 24 men, and this remained generally constant for all subsequent boats (except the ex-Italian and KS and LS boats). This comprised a commanding officer (usually an Oberleutnant zur See), a Chief Boatswain (Oberbootsmann), a Helmsman (Matrosen-Gefreiter), about six seamen including those operating semaphore and engine telegraph posts (Matrosen), a Chief Engineer (Obermaschinist), three engineer NCOs (Maschinenmaaten), six engine-room ratings (usually Heizer), two radio operators (Funkgefreiter or Funkgast) for radio communications including decoding, and a torpedo mechanic (Torpedomechanikergefreiter) who doubled as the boat's cook.

Crew members could earn an award particular to their work —Das Schnellbootkriegsabzeichen— denoted by a badge depicting an E-boat passing through a wreath. The criteria were good conduct, distinction in action, and participating in at least twelve enemy actions. It was also awarded for particularly successful missions, displays of leadership or being killed in action. It could be awarded under special circumstances, such as when another decoration was not suitable.

Operations with the Kriegsmarine
E-boats were primarily used to patrol the Baltic Sea and the English Channel in order to intercept shipping heading for the English ports in the south and east. As such, they were up against Royal Navy and Commonwealth, e.g., Royal Canadian Navy contingents leading up to D-Day, motor gunboats (MGBs), motor torpedo boats (MTBs), motor launches, frigates and destroyers. They were also transferred in small numbers to the Mediterranean, and the Black Sea by river and land transport. Some small E-boats were built as boats for carrying by auxiliary cruisers.

E-boats were organisationally under the command of the Seekriegsleitung or SKL (the naval warfare command, responsible for the planning,execution and direction of naval warfare), and were administratively organised into flotillas, each originally comprising 8 boats. Consequently most orders for new construction were placed in batches of eight boats, or of multiple of eight. The first half-flotilla (1st Schnellbootshalbflotille) was formed in July 1932, but was reorganised as 1st Schnellbootsflotille in June 1935. A second flotilla was established in August 1938, and a third in 1940. Eventually there were fourteen operational flotillas, numbered 1st to 11th plus 21st, 22nd and 24th, together with three training flotillas (Schnellbootsschulflotille). Each flotilla required the backup of a depot ship; initially this was provided by the converted steamer Nordsea, but from 1934 a series of purpose-built tenders were commissioned - the Tsingtau in 1934, followed by the Tanga (in 1939), Carl Peters and Adolf Lüderitz in 1940, and finally the Herman von Wissmamm and Gustav Nachtigal.

E-boats of the 6th & 9th flotillas from Cherbourg attacked Exercise Tiger on 28 April 1944, causing about 749 American Army and Navy casualties.

The E-boats of the 9th flotilla were the first naval units to respond to the invasion fleet of Operation Overlord. They left Cherbourg harbour at 5 a.m. on 6 June 1944. On finding themselves confronted by the entire invasion fleet, they fired their torpedoes at maximum range and returned to Cherbourg.

During World War II, E-boats claimed 101 merchant ships totalling 214,728 tons. Additional claims include 12 destroyers, 11 minesweepers, eight landing ships, six MTBs, one torpedo boat, one minelayer, one submarine, and a number of smaller craft such as fishing boats. They also damaged two cruisers, five destroyers, three landing ships, one repair ship, one naval tug, and numerous other merchant vessels. Sea mines laid by the E-boats sank 37 merchant ships totalling 148,535 tons, a destroyer, two minesweepers, and four landing ships.

E-boat crews were awarded 23 Knight's Cross of the Iron Crosses and 112 German Crosses in Gold.

Operations in the Black Sea
To boost Axis naval strength in the Black Sea, the OKW ordered to the region the transfer of six E-boats of the 1st S-flotilla, the last to be released from action in the Baltic Sea before refit. The Romanian port of Constanța, in the Black Sea, was chosen as the S-flotilla's headquarters. Transporting the six boats overland from Germany to Romania was an impressive logistical feat. The superstructure and all weapons were removed, leaving only the hull. After a long road journey of 60 hours, the boats arrived at Ingolstadt, where they were transferred back to water and towed towards Linz. Upon reaching the Austrian city, the superstructure was rebuilt, then the journey continued down the Danube to Galați, where the main engines were installed. The E-boats then continued on their own power towards Constanța, where refitting was completed.

The first two boats, S26 and S28, arrived in Constanța on 24 May 1942, the second pair, S72 and S102 on 3 June, and the final pair, S27 and S40 10 days later. After the sinking of S27 by a malfunctioning torpedo, four more reserve boats, S47, S49, S51 and S-52 were dispatched to the Black Sea, in order to replace boats undergoing maintenance. S28, S72 and S102 were soon relegated to the Constanța Shipyard for engine replacement, leaving only S26 and the newly commissioned S49 operational. On 1 January 1944, the 1st S-flotilla numbered six operational boats: S26, S42, S47, S49, S52 and S79, while S28, S40, S45 and S51 were all out of commission, undergoing repair in Constanța. Three more boats were shipped down the Danube and were being reconstructed at Constanța. On 1 June 1944, 8 boats were operational in Constanța: S28, S40, S47, S49, S72, S131, S148 and S149. The boats were however penned in harbor, due to fuel shortage. During July, S26, S28, S40 and S42 were transferred to Sulina at the mouth of the Danube, where S42 was fitted with a new propeller. They were joined by S72 in early August, the rest of the boats remaining in Constanța. On 19 August, S26, S40 and S72 were destroyed in port by a Soviet air attack. On 22 August S148 hit a mine and sank near Sulina, and on the following day, S42, S52 and S131 were destroyed in Constanța by a Soviet air attack. What remained of the S-flotilla was disbanded after Romania switched sides on the same day.

Yugoslav Navy
Eight E-boats were built by Lürssen, Vegesack for the Yugoslav Navy from 1936 to 1939. These were named Orjen, Durmitor, Suvobor, Kajmakcalan, Velebit, Dinaira, Rudnik and Triglav. Each measured 28.00 (overall)/27.70 (waterline) x 4.46 x 1.51 m (91 ft 10in/90 ft 10in x 14 ft 4in x 4 ft 11in) and 51 tonnes standard (61.7 tonnes full load). Three Daimler-Benz BF2 petrol engines of 1,100 hp each = 3,300 hp = 33 kts, while they carried 5.8 tonnes of petrrol to give them a radius of 265 nmiles @ 33 knots. Each carried two 550mm torpedo tubes, a 40mm gun and 16 men. Kajmakcalan and Durmitor escaped to Alexandria in April 1941 to join the Allies; the other six fell into Italian hands and became Ms41 to Ms46, four of them eventually captured by the Germans and refitted with standard 533 mm torpedoes (see below under "S2  class").

Italian MS boat
The poor seaworthiness of the Italian-designed MAS boats of World War I and early World War II led its navy to build its own version of E-boats, the CRDA 60 t type, classed MS (Motosilurante). The prototype was designed on the pattern of the six German-built E-boats captured from the Yugoslav Navy in 1941. Two of them sank the British light cruiser HMS Manchester (15) in August 1942, the largest warship to be sunk by fast torpedo craft in the Second World War. After the war these boats served with the Italian Navy, some well into the 1970s.

Service in the Spanish Navy
The Kriegsmarine supplied the Spanish Francoist Navy with six E-boats (S1 to S6) in December 1936 during the Spanish Civil War, and sold six more (S73, S78, S124, S125, S126 and S134) to them in 1943 during the Second World War. Another six were built in Spain with some assistance from Lürssen. A motor boat of the early series, either the Falange or the Requeté, laid two mines off Almería that crippled the British destroyer HMS Hunter on 13 May 1937. The German-built boats were discarded in the 1960s, while some of the Spanish-built ones served until the early 1970s.

Service in China
The Chinese Nationalist Navy had three S7-class boats during the Second Sino-Japanese War. Yue-22 was destroyed by Japanese planes, Yue-371 was sunk by its sailors to avoid being captured by the Japanese soldiers and Yue-253 was captured by the People's Liberation Army during the Chinese Civil War. Yue-253 was renamed "Hoiking" (海鯨), meaning "Seawhale" in Chinese. The People's Liberation Army Navy used it as a patrol boat until 1963.
 * Yue-22 (岳-22)
 * Yue-253 (岳-253)
 * Yue-371 (岳-371)

The Chinese Nationalist government also ordered eight E-boats and a tender, Qi Jiguang (戚繼光). These were all taken over while under construction by the Kriegsmarine in 1939. The E-boats had MB502 diesels and were shorter (by 2.18m) than the standard S26 design of boats. They were re-numbered as S30 to S37, while the Qi Jiguang was renamed Tanga.

Service in the Romanian Navy
Germany sold four E-boats to Romania on 14 August 1944. These vessels displaced 65 tons, had a top speed of 30 knots generated by three Mercedes-Benz engines totalling 2850 hp and were armed with two 500 mm (19.685 in) torpedo tubes. Each of the four boats had a crew of 25. They were numbered 10 to 13 (formerly S151, S152, S153 and S154) and served in the Romanian Navy until at least 1954.

Royal Navy
At the end of the war about 34 E-boats were surrendered to the British. Three boats, S130 (renamed P5230), S208 (P5208) and S212 (P5212) were retained for trials.

Operation Jungle
The Gehlen Organization, an intelligence agency established by American occupation authorities in Germany in 1946 and manned by former members of the Wehrmacht's Fremde Heere Ost (Foreign Armies East), used the Royal Navy's E-boats in order to infiltrate its agents into the Baltic states and Poland. Royal Navy Commander Anthony Courtney was struck by the potential capabilities of former E-boat hulls, and John Harvey-Jones of the Naval Intelligence Division was put in charge of the project. He discovered that the Royal Navy still had two E-boats, P5230 and P5208, and had them sent to Portsmouth, where one of them, P5230 (ex-S130), was modified to reduce its weight and increase its power with the installation of two Napier Deltic engines of 2500 hp each.

Lieutenant-Commander Hans-Helmut Klose was assigned to command a German crew, recruited by the British MI-6 and funded by the American Office of Policy Coordination. The missions were assigned the codename "Operation Jungle". The boats carried out their missions under the cover of the British Control Commission's Fishery Protection Service, which was responsible for preventing Soviet navy vessels from interfering with German fishing boats and for destroying stray mines. The home port of the boats was Kiel, and operated under the supervision of Harvey-Jones. Manned by Klose and his crew, they usually departed for the island of Bornholm waving the White Ensign, where they would hoist the Swedish flag for a dash to Gotland, and there they would wait for orders from Hamburg. The first mission consisted in the landing of Lithuanian agents at Palanga, Lithuania, in May 1949, and the last one took place in April 1955 in Saaremaa, Estonia. During the last two years of the operation, three new German-built motorboats replaced the old E-boats. Klose was later assigned the command of a patrol boat in the Bundesmarine and became commander-in-chief of the fleet before his retirement in 1978.

Royal Danish Navy
In 1947, the Danish navy bought twelve former Kriegsmarine boats. These were further augmented in 1951 by six units bought from the Royal Norwegian Navy. The last unit, the P568 Viben, was retired in 1965.

Royal Norwegian Navy
After World War II, the Norwegian Navy received a number of former Kriegsmarine boats. Six boats were transferred to Denmark in 1951.

Operators

 * Nazi Germany
 * West Germany
 * Kingdom of Italy
 * Kingdom of Romania
 * 🇪🇸 Spain

Survivor
There is just one surviving E-boat, identified as S130. It was built as hull No. 1030 at the Schlichting boatyard in Travemünde. S130 was commissioned on 21 October 1943 and took an active part in the war, participating in the Exercise Tiger attack and attacks on the D-Day invasion fleet.

According to Dutch military historian Maurice Laarman: In 1945, S130 was taken as a British war prize (FPB 5030) and put to use in covert operations. Under the guise of the "British Baltic Fishery Protection Service", the British Secret Intelligence Service MI-6 ferried spies and agents into Eastern Europe. Beginning in May 1949, MI-6 used S208, (Kommandant Hans-Helmut Klose) to insert agents into Lithuania, Latvia, Estonia, and Poland. The operations were very successful and continued under a more permanent organisation based in Hamburg. In 1952, S130 joined the operation and the mission was enlarged to include signal intelligence (SIGINT) equipment. In 1954/55, S130 and S208 were replaced by a new generation of German S-boote.

S130 was returned to the newly formed Bundesmarine in March 1957, and operated under the number UW 10. Serving initially in the Unterwasserwaffenschule training sailors in underwater weaponry such as mines and torpedoes, she later became a test boat under the name EF 3.

S130 was on display in Wilhelmshaven, Germany, having formerly been used as a houseboat.

S130 was purchased and towed from Wilhelmshaven to the Husbands Shipyard, Marchwood, Southampton, England in January 2003, under the auspices of the British Military Powerboat Trust. In 2004, S130 was taken to the slipway at Hythe, where, under the supervision of the BMPT, she was prepared and then towed to Mashfords yard in Cremyll, Cornwall, England to await funding for restoration. In 2008, S130, having been purchased by the Wheatcroft Collection, was set up ashore at Southdown in Cornwall to undergo restoration work involving Roving Commissions Ltd. In July 2020, S130 was still awaiting restoration, with the intention that upon completion it would be a museum-ship at the Richmond dry docks in Bideford, Devon.

Variants and vessels
The Schnellboot design evolved over time. The first groups had a pair of torpedo tubes fitted on the foredeck, but from S26 onwards the forecastle had been raised so that the torpedo tubes were built into the structure.

S1
The first post-WW1 torpedo boat was ordered in November 1929 to be built by Lürssen at Vegesack, near Bremen, in 1930 as their Yard No. 12120, using mahogany and light metal composite. Originally numbered as UZ(S)16, it was commissioned into the Reichmarine on 7 August 1930. It was renamed W1 on 31 March 1931, and then as S1 on 16 March 1932. It measured 26.8 x 4.2 x 1.06 metres (87 ft x 13 ft 9in x 3 ft 6in) and had a displacement of 39 tons standard (50 tons full load). Powered by three Daimler-Benz BF2 12-cylinder 900 hp petrol engines on three shafts, with a rating of 2,700 bhp, it had a sustained speed of 34.2 knots (maximum 39.8 knots). It carried two 500mm (19.685 inch) torpedo tubes and one 20mm flak gun. It had a complement of 12 (later 18) men. Along with the next five boats (S2 to S6), it was stricken on 10 December 1936 and sold to Spain as Badajoz (renamed LT15 in 1939).

The number S1 was re-used in 1939. Five boats had been ordered by Bulgaria from Lürssen, Vegesack, of which the first four were delivered as F1 to F4. The fifth boat was retained in Germany and given the number S1. These were petrol-engined boats, similar to the S2 class built for the Kriegsmarine. Although commissioned in 1939, its petrol engines gave frequent problems, and on 10 September 1940 its stern was rammed (by S13) in Vlissingen, and was later removed from active service.

S2 class
The first production of the E-boat in 1931, a lengthened version of the prototype S1. The first two were ordered from Lürssen on 28 April 1931 and the other two on 16 July 1931. Each measured 27.95 x 4.2 x 1.06 metres (91 ft 8in x 13 ft 9in x 3 ft 6in) and had a displacement of 46.5 tons standard (58 tons full load). Powered by Daimler-Benz petrol engines on three shafts, with a rating of 3,300 bhp, they had a speed of 33.8 knots. Armament and men as in S1. They formed a "Half Flotilla" and were used for training crews for later E-boats; all were stricken on 10 December 1936 (along with S1) for transfer to Spain.

The numbers S2 to S5 were re-used in 1943. Eight petrol-engined boats similar to the original S2 class had been ordered from Lürssen, Vegesack, and completed in 1937-39 for that navy as Orjen, Durmitor, Suvobor, Kajmakcalan, Velebit, Dinaira, Rudnik and Triglav. When Italy occupied Yugoslavia in April 1941, two of them (Durmitor and Kajmakcalan) escaped to Alexandria and served with the Allied forces, while the other six were commissioned into the Italian Navy as Ms41 to Ms46. In September 1943 Ms41 (ex Orjen) at Monfalcone and Ms45 (ex Suvobor) at Cattolica were scuttled, while the other four were captured by the Germans on 9 September and renamed S2 (ex Velebit), S3 (ex Dinara), S4 (ex Triglav) and S5 (ex Rudnik); all four were scuttled by the Germans at Salonika in October 1944.

S6
The first diesel-powered boat was also ordered from Lürssen, Vegesack on 28 August 1932. Its dimensions and other details were the same as for S7 to S9. It was stricken and sold to Spain on 10 December 1936 (together with the preceding petrol-engined boats) and renamed Toledo (renamed LT14 in 1939 and stricken in 1942).

S7 class
Built from 1933 onwards. Similar to S6, but with an improved hull form, these were the first operational diesel boats. The first three, ordered (together with S6) on 26 August 1932, were fitted with MAN L7 19/30 diesels on three shafts giving a speed of 36.5 knots and measured 75.8 tonnes standard (95 tonnes full load), while the last four - ordered on 20 July 1932 - were equipped with the more reliable Daimler-Benz MB502 diesels of 3,960 hp to produce 35 knots, and were 78 tonnes standard (92 tonens full load). They had a fuel capacity of 10.5 tonnes, giving them a radfius of 600 nmiles @ 30 knots. All measured 32.36 x 5.06 x 1.36 m (106 ft 2in x 16 ft 6in x 4 ft 6in) except that S10 to S13 had a draught of 1.42m (4 ft 8in). These carried the larger 533mm (21-inch) torpedoes rather than the 500mm of the petrol-driven boats; two torpedo tubes were mounted on the forecastle, and the boats also carried a single 20mm MgC/30 gun, with a crew of 18 (later 21) men.

S14 class
Improved S7 type, ordered on 16 July 1934 (first two) and 5 November 1935 (last two) with new MAN L11 (11-cylinder) engines producing 6,150 hp, which proved unsatisfactory. Enlarged hull, measuring 34.62 x 5.26 x 1.67 m (113 ft 7in x 17 ft 3in x 5 ft 6in) and displacing 92.5 tonnes standard (105.4 tonnes full load). After S17 was broken up, the surviving three boatrs were transferred to the Fast A/S Group in 1940.

S18 class
Built from 1937 onwards. Two new boats were ordered on 21 December 1936 (S18 and S19) and six more boats (S20 to S25) on 29 December 1937. Almost identical to the S14 class, but with 3 Mercedes Benz MB501 engines (of total 6,000 hp) instead of MAN engines. The bridge, which had been in front of the wheelhouse on earlier designs, was raised to the wheelhouse roof to increase all-round visibility.

1938 Orders
In May 1938 it was planned to order six additional boats every year until 1943 (thus providing a projected S26 to S61). However, a speeding-up of production was decided on. Twelve additional boats were ordered - all from Lürssen - in August 1938. These were of two different models, due to accommodating different Daimler-Benz diesels.

S26 class
The larger type (S26 to S29), were ordered on 2 August, and entered service in 1940. Beginning with this model, the two torpedo tubes on the foredeck were encased within a high forecastle deck. This type were slightly lengthened from the S18 design so that the engine compartments could accommodate the larger 20-cylinder diesels, they measured 34.94 x 5.28 x 1.67 m (114 ft 8in x 17 ft 4in x 5 ft 6in), giving a displacement of 92.5 tons (112 tons full load). These dimensions would be retained for all subsequent boats (except for the somewhat smaller S30 class), as the basic design and layout would remain unchanged. The three Daimler Benz engines each produced 2,500 hp for a total rating of 7,500 hp, providing 41 knots.

S30 class
The other eight boats (S30 to S37) were 2.18 m (7 ft 2in) shorter than the S26 type and 22 cm (8.66 in) narrower. This is because their engines were the 16-cylinder (2,000 hp) Daimler-Benz MB502 diesels. They were originally ordered on 9 August (a week after S26 to S29) for the Chinese (Nationalist) Navy (the last two initially from Naglo, Berlin, but the contract was later switched to Lürssen), and were sequestered for use by the Kriegsmarine. As they were already under construction at the outbreak of war, they were mostly completed before the S26 type boats.

1939 Orders
24 more boats were ordered - all from Lürssen (S44 and S45 were first scheduled to be built by Stettiner Oderwerk, but in the event all of this batch were contracted to Lürssen - on 24 September 1939. The pre-war Mobilisation New Construction Programme had called for 48 new boats per year, but this target was raised to 60 boats in September 1939 by the Naval War Staff. They called for a fleet level of 40 to 50 operational boats, with 16 being built annually as replacements. Sixteen were virtually identical with the S26 type (measuring 34.94 m in length and with 20-cylinder MB501 diesels), other than simplified ventilators and other minor changes. This design was to provide almost all of the Schnellboote built in Germany for the rest of the war.

While until this date all boats had been procured from Lürssen, but the German Navy had been seeking a second yard to add to its construction capacity, and on 25 September a contract for eight boats (numbered from S101 to S108) to the standard S26 design was awarded to Schlichting-Werfk at Travemünde. This second builder was assigned a new series of numbers in the "101 range to distinguish them from the Lürssen boats.

Following the outbreak of war, another eight boats were ordered from Lürssen on 14 November 1939 to the same Schnellboot 1939 design as the S30 group (measuring 32.76 m in length and with 16-cylinder MB502 diesels),

1940 orders
On 4 June 1940 a further batch of boats to the S26 design was ordered. This comprised 8 boats from Lürssen (S62 to S69) and 9 boats from Schlichting (S109 to S117). S67 introduced an improved design with a partially armour-plated cupola (the Kalotte or skull cap) over the bridge, providing protection from weather as well as small arms fire, with a lower profile. From 1943 orders onwards, this armoured bridge became standard, and was also retro-fitted to many of the earlier boats. Various armaments were carried including 40 mm Bofors or 20 mm Flak aft, MG34 Zwillingsockel midships. (Note the designation '38b' sometimes seen is not Kriegsmarine nomenclature and originated in a postwar American hobby publication).

Following the German occupation of France in June 1940, the Naval War Staff decided that 160 E-boats were now needed (comprising 26 flotillas), with 8 flotillas based in France and 6 each in Norway, the Baltic and the North Sea. On 26 August an additional four boats (S70 to S73) were ordered from Lürssen, and in December Schlichting were given another order, this time for eight boats (S118 to S125),

1941 orders
Another 40 boats were ordered in 1941, 16 from Lürssen on 3 January (numbered S74 to S89), another 16 from the same yard on 18 September (numbered S90 to S100 and from S134 to S138) and 8 from Schlichting at Travemünde (S126 to S133), also on 18 September.

1942 orders
Orders for a further 16 boats were given to Lürssen on 24 February 1942. The first 12 of these were numbered S139 to S150; the next sixteen numbers were allocated to construction at Schiedam in Holland, so the final four of the Lürssen batch were numbered S167 to S170.

S151 class
Eight smaller torpedo boats were building for the Dutch Navy at Gusto Werf, Schiedam (near Rotterdam) as TM54 to TM61 inclusive. When Holland was occupied by the Germans, these were seized and completed (with some design modifications) by German and Dutch shipyard workers and renumbered as S151 to S158. They measured 28.3 x 4.46 metres (92 ft 10in x 14 ft 7in), displacing 57 tons. Originally the Germans planned to sell these to Bulgaria, and they were formed as the new 7th S-flotilla in October 1941, but the Kriegsmarine's need for them in the Mediterranean had caused them to be sent south via the French inland waterways. They were authorised to transfer to the Mediterranean on 15 July 1942, and arrived there on 8 October, finally reaching Augusta, Sicily on 15 December, when they became operational. Eight further vessels had been intended by the Dutch Navy as TM62 to TM70, and material had been collected for their construction at Schiedam. They were cancelled with the German occupation in May 1940; they were re-ordered (as S159 to S166) from Gusto Werf on 11 July 1941, but construction of these stopped in April 1942.

Continuation of S139 batch

All these were part of the order placed on 24 February 1942, and the first three were identical to S139 batch. However the final boat, S170, was the prototype (along with S228 at Travemünde) for the final series of boats ordered in December 1943 (few of which were completed) with the first MB518 engines of 3,000 hp for evaluation; her details were the same as for that final series of orders.

1943 orders
Needing to increase production, orders for two batches of vessels were placed during the first half of 1943, totalling sixty boats. An order for sixteen boats was placed with Lürssen's yard on 15 January 1943 (S171 to S186), and another order for eight boats with Schlichting at Travemünde on the same day (S187 to S194). On 7 May another batch was ordered from the same builders - twenty-four from Lürssen (S195 to S218) and twelve from Schlichting (S219 to S230), although the final two from the Schlichting order were seemingly deferred, to be re-included in the much larger order placed in December.

Like the S139 batch, almost all of these were a metre longer than the original S26 class in order to have room to fit the new supercharged MB511 engines. The sole exception was S228 - the final boat from this batch to be completed at Travemünde, which was that yard's prototype for the final mass series which were ordered in December 1943, built to carry the new MB518 diesels, and was thus the equivalent test-bed at that yard to S170 from Lürssen. All the other 57 boats completed from this batch had MB 511 diesels fitted.

The final batch ordered on 4 December 1943 comprised a massive total of 282 units - S229 to S260 (32 boats) from Schlichting; S301 to S425 (125 boats) from Lürssen; and S701 to S825 (125 boats) from Danziger Waggon at Danzig. The first four of the Schlichting boats (S229 to S230) were completed by April 1945 but not placed into service; these were presumably broken up in the shipyard following the cessation of hostilities. Of the projected numbers from the other two builders only the first five from Lürssen and 9 from Danzig were completed. Another seven were launched but not completed; these were scuttled in the North Sea, while fourteen more were scrapped in the Lürssen shipyard (S308 to S328) and others at Travemünde and Danzig. The remainder were all cancelled.

S501 class
These small ex-Italian Navy boats of the Baglietto fast type (or MAS526 type) were taken over by the Germans in the Black Sea on 20 May 1943. The first seven of these measured 18.7 x 4.7 x 1.5 m (61 ft 4in x 15 ft 5in x 4 ft 11in) and displaced 25.2 tons (29.4 tons full load). These 2-shaft boats were driven by 2 Isotta-Fraschini petrol engines of 2,000 hp to reach 42 knots. They carried two 450mm torpedoes plus one MG or 20mm gun, and 6 depth charges, with a crew of 10. All 7 were transferred to the Romania in August 1943, but seized by the USSR on 5 September 1943.

S601 class
Further small ex-Italian Navy boats of the Baglietto fast type (of various classes) were taken over by the Germans.

S700 class
Late war design proposal with stern torpedo tubes and 30 mm gun turret forward. These were intended to be slightly larger, of prefabricated construction, and to be propelled by the supercharged MB518 engines. They were to have carried two stern-firing torpedo tubes in addition to the usual two bow tubes, with a special 30mm gun in a bow turret. These were ordered from Danziger Waggonfabrik at Danzig on 4 December 1943 as S701 to S825 (125 boats), but only the first nine boats were built, and these were completed to S100 design specification with MB511 diesel engines after the production of the MB518 engine was cancelled due to Allied bombing. The other boats were cancelled or scrapped unfinished in the shipyard.

In the 1944 Programme it was intended to increase production of E-boats to deliver 150 boats per annum, but this level was never achieved. In November 1944 there were 292 boats on order, of which 138 were under construction, usually awaiting delivery of the new MB518 engines, while the other 154 boats were unstarted. Eventually, as the ability to provide engines increased, only 19 of the 138 boats were actually completed.

KS-boats (Kleinst Schnellboote), originally KM-series (Küstenminenleger)
A class of small fast attack craft designed as offensive mine-layers (rated Küstenminenleger),able to carry up to 4 mines, and to operate close to enemy shores. They measured 15.95 x 3.50 x 1.10 m (52 ft 4in x 11 ft 6in x 3 ft 7in); 15/16 tonnes standard (18/19 tonnes full load). Powered by 2 BMW MB507 12-cylinder aero engines producing 1,650 hp (32 knots), although four boats (nos. 1, 2, 5 and 6) had two Junkers 4-cylinder diesels of 1,500 hp to produce speeds of 30/40.9 knots; radius 225 miles at 25 knots. A total of 36 were ordered (most on 29 and 31 July 1940, but KM1 to KM4 were ordered on 26 August, and KM25 and KM26 on 11 October 1940), but as their engines proved unreliable, they were not used in their intended role and instead most were employed in lakes and rivers, being attached to the Peipusee Flotilla (KM3 to the Ladogasee Flotilla). As minelayers they carried four TMB mines and a single Mg39 gun, plus a crew of 6. 21 boats were equipped with 2 x 450mm fixed stern torpedo tubes replkacing the mines, and were reclassed as KS-boats (Kleinst Schnellboote), retaining their original numberss but replacing the "KM" prefix by "KS". Of the unreclassified boats, KM27 to KM30 were all sunk by Soviet aircraft in the Gulf of Bothnia during 1943.

LS-boats (Leichte Schnellboote)
Another class of even smaller fast attack boat, not intended to operate independently, but to be based on auxiliary cruisers or other vessels operating in overseas areas. They measured 12.50 x 3.46 x 1.02 m (41 ft x 11 ft 4in x 3 ft 4in). These 2-shaft boats weighed 11.5 - 13 tons. The first six were powered by two Junkers 6-cyl JuMo205 aircraft engines, they reached 38 knots. Later boats had two Daimler-Benz MB507 12-cyl diesels of 2,000 hp reaching 40.9 knots, and with an endurance of 300 miles at 30 knots. They carried two 450mm torpedo tubes (instead of up to 4 mines), but had depth charges and a single 20mm MG (in an enclosed turret), plus 7 men. A total of 34 of these boats were ordered, the prototype from Naglo Werft, Berlin, and all the others from Dornier Werft, Friedrichshafen, but the prototype was not completed and only the next eleven were completed; another six (LS13 to LS18) were taken over by France incomplete following the war's end, and completed for them; the final 16 (LS19 to LS34) were cancelled in 1944.

Source: https://www.german-navy.de/kriegsmarine/ships/index.html