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.^[8] 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".^[9] 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.^[10]

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 administratively organised into flotillas, each originally comprising 8 boats. The first 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.

Schnellboot S1

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.^[12] They left Cherbourg harbour at 5 a.m. on 6 June 1944.^[12] On finding themselves confronted by the entire invasion fleet, they fired their torpedoes at maximum range and returned to Cherbourg.^[12]

During World War II, E-boats claimed 101 merchant ships totalling 214,728 tons.^[13] 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.^[13]

E-boat crews were awarded 23 Knight's Cross of the Iron Crosses and 112 German Crosses in Gold.^[13]

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 4.30 x 1.51 m (91 ft 10in/90 ft 10in x 14 ft 1in x 4 ft 11in) and 61.7 tons full load. Three Daimler-Benz petrrol engines of 1,100 hp each = 3,300 hp = 41 kts. 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 (see below under "S2 class").

Italian MS boat

Italian MS 472, post-war configuration

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 six German-built E-boats captured from the Yugoslav Navy in 1941. Two of them sank the British light cruiser HMS Manchester in August 1942, the largest warship to be sunk by fast torpedo craft in the Second World War.^[21] After the war these boats served with the Italian Navy, some well into the 1970s.^[22]

Service in the Spanish Navy

The Kriegsmarine supplied the Spanish Francoist Navy with six E-boats (S1 to S6) during the Spanish Civil War, and six more 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.^[23]

Service in China

This is one of the S-7-class boats, S-13. The Chinese Navy operated three boats of this class.

The Chinese Nationalist Navy had three S7-class boats during the Second Sino-Japanese War.

• Yue-22 (岳-22)
• Yue-253 (岳-253)
• Yue-371 (岳-371)

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.

The Chinese Nationalist government also ordered eight S30-class E-boats and a tender, Qi Jiguang (戚繼光). These were taken over by the Kriegsmarine in 1939. Qi Jiguang was renamed Tanga.

Service in the Romanian Navy

Germany sold four E-boats to Romania on 14 August 1944.^[24] These vessels displaced 65 tons, had a top speed of 30 knots generated by three Mercedes-Benz engines totalling 2,130 kW (2,850 hp) and were armed with two 500 mm (20 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.^[25]

Post-war service

Operators

S1

The first post-WW1 torpedo boat was ordered in November 1929 to be built by Lürssen at Vegesack, near Bremen, in 1930, 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 in 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 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 sold to Spain on 10 December 1936 and renamed Badajoz (LT15).

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. 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 transferred to Spain in 1936, along with S1 and S6.

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.^[35] 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, also built by Lürssen, Vegesack in 1933. Its dimensions and other details were the same as for S7 to S9. Ordered on 26 August 1932, it was sold to Spain on 10 December 1936 (together with the preceding petrol-engined boats) and renamed Toledo (LT14).

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 diesels and measured 80 tons standard (95 tons full load), while the last four were equipped with the more reliable Daimler-Benz diesels and were 78 tons standard (92 tons full load). All measured 32.40 x 4.90 x 1.21 m (106 ft 3in x 16 ft x 4 ft). 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 gun, with a crew of 21 men.

S14 class

Improved S7, built from 1934 onwards. Enlarged hull.

S18 class

Built from 1937 onwards. Almost identical to the S14 class, but with 3 Mercedes Benz engines instead of MAN engines. The bridge, which had been in front of the wheelhouse on earlier designas, was raised to the wheelhouse roof to increase all-round visibility.^[36]

1938 batches

Twelve additional boats were ordered - all from Lürssen - in August 1938. These were of two different models, due to accommodating different Daimler-Benz disels. The larger type (S26 to S29), were begun in 1939, 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 5.10 x 1.52 m (114 ft 8in x 16 ft 9in x 5 ft, giving a displacement of 92.5 tons (115 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.

Schnellboot-26

The other eight boats (S30 to S37) were 2.18 m (7 ft 2in) shorter than the S26 type and 20 cm (8 in) narrower. This is because their engines were the 16-cylinder (2,000 hp) Daimler-Benz MB502 diesels. They had originally been ordered for the Chinese (Nationalist) Navy, 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 batches

24 more boats were ordered - all from Lurssen - on 28 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.^[39] This design was to provide almost all of the Schnellboote built in Germany for the rest of the war.

The other eight boats were to the same design as the S30 type (measuring 32.76 m in length and with 16-cylinder MB502 diesels),

When Germany occupied 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 Norwat, the Baltic and the North Sea.^[39]

1941 batches

Another 30 boats were ordered in 1941, 20 from Lürssen (numbered S62 to S81) and 10 from Travemünde (S107 to S116). 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).

S101 class

While the first hundred E-boats had all been ordered from Lürssen, the next twenty-six were all ordered from Travemünd - six in 1940, ten in 1941 and another ten in 1942. These carried 1 × 20 mm in the bow, 2 × 20 mm gun amidships and a 37 mm gun aft. Another twenty-four boats were ordered in 1943, twelve from Travemünd and twelve from Lürssen.

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.^[41]

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 in 1941, but construction of these stopped in April 1942.

S167 class

Repeats of the S101 series, a further order for twenty boats was begun at Lürssen's yard in late 1943, and another eight at Travemünd.

A further 42 units were ordered from Schlichting Travemünde in 1944. Of these only the first ten were placed in service, while the next four (S229 to S232) were completed in April 1945 but not placed into service; these were presumably broken up in the shipyard following the cessation of hostilities. The remaining 28 (S233 to S260) were cancelled.

The final batch ordered from Lürssen in 1944-45 comprised 125 units (S301 to S425). Of these only the first seven were completed. Another seven were launched but not completed; these were scuttled in the North Sea, while fourteen more were scrapped in the shipyard (S308 to S328). The final 97 (S329 to S425) were 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.^[35] 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)^[35] 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 as S701 to S825 (125 boats), but only the first nine boats were built, and these were completed to S100 design specification after the production of the MB518 engine was cancelled due to Allied bombing. The other boats were cancelled or scrapped unfinished in the shipyard.

Schnellboot S701 in April 1945. This torpedo boat was part of the 8th flotilla based in Ijmuiden. The S701 had been delivered to the Kriegsmarine in July, 1944. It was surrendered to the U.S. Navy in 1945 and then sold to the Dutch Navy.

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 15 ft 10in x 3 ft 8in); 18/19 tons. Powered by 2 BMW 12-cylinder aero engines producing 1,650 hp (32 knots); radius 225 miles at 25 knots. A total of 36 were ordered, 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). 21 boats were equipped with 2 x 450mm torpedo tubes and 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 tuubes (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