In the simplest terms, the Navy under the Naval High Command (Oberkommando der Kriegsmarine) was split into three main operational commands: the Flottenchef, covering the major combat units of the Fleet, and the Kommandierender Admiral der Marinestationen der Nordsee and der Ostsee, the Commanding Admirals of the North Sea and Baltic Naval Stations.
Under these latter two senior commands came the Befehlshaber der Sicherung der Nordsee and der Ostsee, Commanders of Security in the North Sea and Baltic.
On the outbreak of war in September 1939 the position of Befehlshaber der Sicherung was held by a flag officer with the rank of Konteradmiral. As more and more territory, and thus coastal waters, fell under German control, so new senior naval commands were established (e.g. in Paris, Oslo, Sofia, etc), and each had a number of units of the Sicherungsverbände under its control. In November 1944, as German-controlled waters rapidly shrank, Sicherungsverbände units were grouped under the command of the Befehlshaber der Sicherungstreitkräfte or Commander of Security Forces. Below these senior levels in the chain of command came the positions of Führer der Minensuchboote and Führer der Vorpostenboote, Commanders of Minesweepers and of Patrol Boats.
For the greater part of the war those naval units (usually of flotilla size) responsible for minesweeping, minelaying, patrol and escort work were grouped into Security Divisions or Sicherungsdivisionen – of which 11 were ultimately created, plus one training unit, the Sicherungslehrdivision. For example, in 1941, I. Sicherungsdivision comprised the following units:
15. Minensuchflottille
22. Minensuchflottille
32. Minensuchflottille
34. Minensuchflottille
13. Vorpostenflottille
A trio of minesweepers – 66, 98 & 145 – tied up in port before the war. Although they are finished in the old black colour scheme, under magnification one can still see the large bronze eagle-and-swastika mounted on the front of the bridges of 98 and 145. This dates the photo to 1935 at the earliest, when the Reichsmarine was re-formed as the Kriegsmarine. (Author’s collection)
20. Vorpostenflottille
Minenräumschiff 12
Sperrbrecher 145, 147, 148 & 149
As early as 1940, a special badge was introduced to recognize the service of personnel involved in such essential duties. Designed by the respected Berlin graphic artist Otto Placzek, it was authorized on 31 August 1940 by Grossadmiral Raeder, and entitled the Kriegsabzeichen für Minensuch-, U-Bootsjagd- und Sicherungsverbände (War Badge for Minesweeper, Sub-Chaser and Security Units). Awards began on 11 September of that year, the badge being available to those who had completed a minimum of three combat missions. Like the other War Badges of the armed services, this was issued together with an award document; it was recorded in the individual’s pay book and service records, and was worn on the left breast of uniforms.
The metal badge consisted of a vertical oval wreath of oakleaves topped by the eagle with a tiny swastika in its talons. In the centre of the wreath was a waterspout rising from the sea, which could indicate either a detonating mine in the mine-clearing role, or a detonating depth charge in the sub-chaser role. The wreath and eagle were gilded, surrounding a silvered waterspout on a toned silver sea. The reverse featured either a vertical or horizontal hinged pin fitting.
The badge was re-authorized in 1957 with the eagle and swastika removed, for wear by veterans or those still serving in the Bundesmarine.
At the time the Kriegsmarine was formed in 1935 many of its existing minesweepers were rather elderly veterans of the Great War. The first modern class to be introduced was the Minensuchboot M35. This proved to be a successful and highly seaworthy vessel with a relatively powerful armament for vessels of this category. It was, however, of fairly complex construction and expensive to produce. The powerplant required extensive and careful maintenance by skilled technicians, a situation that may have been acceptable in peacetime but was less so after wartime manpower demands put great pressure on the numbers of such skilled personnel available. During the latter part of the war the fact that these vessels had oil-fired boilers also restricted their use due to fuel shortages.
Minesweepers were not named, but were given a pennant number prefixed with the letter ‘M’.
The M35 was constructed by a number of different shipyards, and a total of 68 were built. Of this number just over 30 were lost in action during the war. Those that survived were distributed amongst the Allies, with 17 given to the US Navy, 13 to the Soviets, and 5 to the Royal Navy. The US Navy returned five of its M35s to the new German Bundesmarine in the mid 1950s. Production was as follows:
| Shipyard | Vessels | Total |
| Stülken, Hamburg | M1–3, 10, 13–16, 25–28 | 12 |
| Oderwerke, Stettin | M4–6, 11, 17–19, 29–32, 151–156 | 17 |
| Flenderwerke, Lübeck | M7–9, 12, 20–24 | 9 |
| Lübecker Maschinenbaugesellschaft, Lübeck | M33–34, 81–85 | 7 |
| Schichau, Elbing | M35–36 | 2 |
| Atlas Werke, Bremen | M37–39 | 3 |
| Rickmerswerft, Wesermünde | M101–104 | 4 |
| Lindenau, Memel | M131–132 | 2 |
| AG Neptun, Rostock | M201–206 | 6 |
| Deutsche Werft, Hamburg | M251–256 | 6 |
| Specifications: | |||
| Length | 68m | Powerplant | 2x Lentz 3200hp expansion engines |
| Beam | 8.7m | Top speed | 18 knots |
| Displacement | 870 tons | Endurance | 5,000 nautical miles |
| Armament | 2x 10.5cm gun, 1x 3.7cm flak, 2x 2cm flak; 4x depth charge launchers; up to 30 mines | Crew | 107 |
As the war progressed, the need to beef up the anti-aircraft armament on most Kriegsmarine vessels led to the M35 minesweepers having the single 2cm flak mount either side of the bridge replaced with twin mounts, and in some cases the aft single flak mount was replaced with a quadruple 2cm Flakvierling. Light machine guns could also be fitted.
This type was of similar specification to the M35 but utilized a simpler method of construction, and featured coal-fired rather than oil-fired boilers, making them less dependent on Germany’s dwindling oil reserves in the second half of the war. A total of 131 of the class were built, predominantly in shipyards in occupied Holland. These boats did not replace the M35 class, production of which continued. Around half of the M40 boats built were lost in action during the war; of those that survived 25 went to the US Navy, 30 to the Soviets and 13 to the Royal Navy. As with the M35s, five of the boats that had served in the US Navy were returned to the new Bundesmarine in the 1950s. (Interestingly, a handful of this highly successful type were still serving in the Romanian Navy in the mid 1990s.) Production numbers in the various yards were are shown on p.10.
Sailors under training on the forward 10.5cm gun of a minesweeper. Later versions had a protective turret; manning an exposed gun like this in heavy weather must have been quite an experience. (Author’s collection)
A flotilla of minesweepers on operations; the flag bearing the Iron Cross on a horizontal tricolour dates this photo between 1933 and November 1935. These older coal-burning vessels would be the first ship to which many Kriegsmarine sailors would be posted. As wartime oil fuel shortages began to bite, the older coal-burning ships proved valuable once again. (Author’s collection)
An M35 type minesweeper, backbone of the Kriegsmarine’s minesweeper fleet. The wartime censor has made a half-hearted effort to disguise the vessel’s pennant number ‘1’, still just visible below the forward 10.5cm gun turret. (Author’s collection)
As with the M35 type, these boats were eventually up-gunned, the ultimate version carrying one 10.5cm gun, two twin and one single 3.7cm flak, one 2cm Flakvierling, two twin 2cm flak and two machine guns.
 |
MINESWEEPERS 1: Early pre-war type This is one of the minesweepers used by the Reichsmarine, built in about 1919. A number of these vessels continued in service during (and even briefly after) World War II. The usual colour scheme for these coal-burning vessels until 1936–37 was black, as shown. Typical features are the tall narrow funnel and the exposed main armament; enclosed turrets were only added on later models. |
| 2: M35 class The M35 type was the mainstay of the Kriegsmarine’s minesweeper force in World War II. Note the main armament of two 10.5cm guns, now in enclosed turrets. With an additional single 3.7cm and four 2cm anti-aircraft guns, these vessels were much more heavily armed than their predecessors. The plan view shows the rails running along the after deck, along which mines were rolled and dropped over the stern. |
|
| (Detail, left) An essential part of the equipment inventory of any minesweeper was the paravane, resembling a tiny aircraft or winged bomb. These were towed on cables either side of the vessel, their vanes being set to steer them away from the hull on each side to form an arrowhead-shaped swept area. They would snag the anchor cables of enemy mines, which slid down the tow cables into a cutting mechanism on the paravane. Once the mine had bobbed to the surface it could be detonated from a safe distance by gunfire. | |
| (Detail, right) The standard German EMC mine of World War II was attached by a cable to a small trolley which also acted as its anchor. Once it was dropped from the minelayer the cable would unreel, allowing the mine to rise to just below the surface. |
| Specifications: | |||
| Length | 62.3m | Powerplant | 2x 2400hp expansion engines |
| Beam | 8.9m | Top speed | 17 knots |
| Displacement | 775 tons | Endurance | 4,000 nautical miles |
| Armament | 1x 10.5cm gun, 1x 3.7cm flak, 2x 2cm flak; 4x depth charge launchers; up to 30 mines | Crew | 74 |
This port-side view of an M35 class minesweeper shows the distinctive so-called ‘goalpost’ davit for the ship’s launch. Note also the raised flaps on the forward turret, unmasking the optics for the main gun. This vessel is Minesweeper M19, serving with 3. Minensuchflottille. (Author’s collection)
This final minesweeper type to be built for the Kriegsmarine made use of prefabricated sections, so construction could be dispersed and only final assembly required shipyard facilities. Although more than 160 were ordered only 17 were ultimately built, though a number of others were in various stages of completion when the war ended. Far more powerfully armed and, like the M40s, equipped with coal-fired boilers, examples of these vessels served on into the 1960s. Completed production was as follows:
A trio of minesweepers at sea. As well as carrying out basic mine clearing (and minelaying) operations, minesweepers were also used to escort small coastal convoys and for anti-submarine work. Note the liferaft attached to the bridge of the nearest ship. (Author’s collection)
| Shipyard | Vessels | Total |
| AG Neptun, Rostock | M601–612 | 12 |
| Schichau, Königsberg | M801–805 | 5 |
| Specifications: | |||
| Length | 67.8m | Powerplant | 2x 2400hp expansion engines |
| Beam | 9m | Top speed | 17 knots |
| Displacement | 821 tons | Endurance | 3,600 nautical miles |
| Armament | 2x 10.5cm guns, 2x 3.7cm flak, 1x 2cm Flakvierling; 4x depth charge launchers; up to 24 mines | Crew | 90 |
The ubiquitous M35 minesweeper served on virtually every front on which the Kriegsmarine was involved, from the Arctic to the Mediterranean. The 42 minesweeper flotillas were based as follows; note that ‘Channel’ means ‘English Channel’, and active dates which conclude after 1945 refer to units that were maintained post-war for mine clearing under Allied control:
Any coastal vessels operating in Western waters ran the risk of attack by British aircraft. Judging from the victory tally on the bridge, this crew considered themselves more than capable of putting up a robust defence. Under magnification nine plane silhouettes can be made out, all dated 1941 or 1942; six are in solid black, three in outline only, and the two at the tips of the arc-shaped display are specifically shown as twin-engined types. In the centre of the arc is the faint white outline of what may be an MGB. (Author’s collection)
 |
M35 MINESWEEPER |
| This sectional view shows a typical minesweeper of this class. These small warships were designed for use in coastal waters, and, compared to larger vessels, they spent limited time at sea on any one cruise, so they were provided with little in the way of accommodation. The forward part of the hull, under the forward gun turret, contained the junior ratings’ accommodation, with the petty officers’ quarters immediately below. The lowest deck in this area housed the ship’s stores and the magazine for the forward turret. | |
| Midships were the No.1 and No.2 boiler rooms, venting into a single funnel. Immediately aft of the boiler rooms was the electrical generator, with the ship’s galley above it. | |
| Further aft is the engine room, with two Lentz steam turbines driving twin screws. In the lowest level aft of the engine room were further stores compartments, another electrical generator room, and the magazine for the aft turret. Immediately above this was the accommodation for officers and senior ranks. | |
| Just aft of the stern turret the paravanes can be seen lashed to the railings. Also visible towards the aft end of the deck are a number of mines on their wheeled trolleys, ready to be dropped over the stern. | |
| Just forward of the stern 2cm Flakvierling gun is a 1m optical rangefinder for this weapon; the 3m rangefinder which controlled the main armament is mounted on the bridge. | |
| Slung from ‘goalpost’ davits on the starboard side just aft of the funnel is a large motor pinnace, and a small jollyboat is carried on the port side. In addition one or more small liferafts were carried, often mounted on the sides of the forward turret or on the face of the bridge. |
KEY
1 Stern derricks
2 Mines
3 Aft 10.5cm turret
4 2cm Flakvierling
5 Ship’s launch
6 Launch gantry
7 Ship’s boat
8 Funnel
9 Crows Nest
10 Searchlight
11 Main armament rangefinder
12 Bridge
13 Forward 10.5cm turret
14 Bosun’s Room
15 Office
16 Mess
17 Magazine
18 Junior NCO accommodation
19 Ship’s stores
20 Crew accommodation
21 Boiler No. 2
22 Boiler No. 1
23 Stabiliser compartment
24 Electrical generator room
25 Engine room
26 Ship’s stores
27 Senior NCO accommodation
28 Senior NCO accommodation
29 Officer accommodation
30 Twin propellers
31 Twin rudders
| Flotilla | Location | Active |
| 1. MS-Flottille | Baltic/North Sea | 1924–45 |
| 2. MS-Flottille | Baltic/North Sea | 1936–44 |
| 3. MS-Flottille | Norway/Baltic | 1940–45 |
| 4. MS-Flottille | North Sea/Atlantic coast | 1939–45 |
| 5. MS-Flottille | Norway/North Sea/Baltic | 1940–47 |
| 6. MS-Flottille | North Sea/Atlantic coast | 1939–44 |
| 7. MS-Flottille | Baltic/North Sea | 1939–45 |
| 8. MS-Flottille | Atlantic coast | 1941–45 |
| 9. MS-Flottille | Norway | 1943–47 |
| 10. MS-Flottille | Atlantic coast | 1943–44 |
| 11. MS-Flottille | North Sea/Baltic/Norway | 1939–45 |
| 12. MS-Flottille | Baltic/North Sea | 1939–47 |
| 13. MS-Flottille | Baltic/North Sea | 1939–42 |
| 14. MS-Flottille | North Sea | 1939–41 |
| 15. MS-Flottille | Baltic/Norway | 1939–43 |
| 16. MS-Flottille | North Sea/Channel | 1939–43 |
| 17. MS-Flottille | Baltic/North Sea/Norway | 1939–42 |
| 18. MS-Flottille | North Sea/Channel/Norway | 1939–42 |
| 19. MS-Flottille | Baltic/Norway | 1939–43 |
| 21. MS-Flottille | North Sea/Norway/Baltic | 1942–45 |
| 22. MS-Flottille | North Sea/Norway/Baltic | 1942–45 |
| 23. MS-Flottille | Norway/Baltic | 1942–47 |
| 24. MS-Flottille | Channel Islands | 1942–45 |
| 25. MS-Flottille | North Sea/Norway/Baltic | 1942–45 |
| 26. MS-Flottille | French coast | 1943–44 |
| 27. MS-Flottille | North Sea/Holland | 1943–45 |
| 28. MS-Flottille | Atlantic coast/Channel | 1943–44 |
| 29. MS-Flottille | Kattegatt/Skagerak | 1943–45 |
| 30. MS-Flottille | Norway | 1943–45 |
| 31. MS-Flottille | Holland/Baltic | 1940–45 |
| 32. MS-Flottille | Holland | 1940–44 |
| 34. MS-Flottille | Holland | 1940–45 |
| 36. MS-Flottille | Holland/Baltic | 1940–45 |
| 38. MS-Flottille | Channel/Holland/Kattegat | 1940–45 |
| 40. MS-Flottille | French coast | 1940–44 |
| 42. MS-Flottille | French coast | 1940–44 |
| 44. MS-Flottille | French coast | 1940–44 |
| 46. MS-Flottille | French coast | 1942–45 |
| 52. MS-Flottille | Norway | 1941–45 |
| 54. MS-Flottille | Norway | 1940–44 |
| 56. MS-Flottille | Norway | 1940–45 |
| 70. MS-Flottille | Mediterranean | 1943–44 |
The officers and crew of a minesweeper mustered on the foredeck for a group photo. The fact that the captain wears the ribbon of the Iron Cross in his buttonhole indicates that the photo was taken after the outbreak of war. By this time most vessels had had the large bronze eagle removed from the front of the bridge for safekeeping, but it is present here. The left-hand lifebelt or fender is lettered ‘1. Minensuch-Flottille’. (Author’s collection)
The Räumboote (R-boats) were basically small motor minesweepers for inshore work, often doubling as patrol boats or escorts. The first was ordered in 1930 from the firm of Lürssen, the principal manufacturer of S-boats, and indeed there was a resemblance in appearance between R-boats and S-boats, the principal difference being that the former did not carry torpedoes. The first batch consisted of 16 boats, with R1–R8 displacing 43 tons and R9–R16 increased to 52 tons. Armament consisted of only a single heavy machine gun and up to six mines. These earlier boats can be easily identified in photographs by the raised forecastle in contrast to the flush-decked appearance of later boats.
A larger version was introduced in 1934; R17–R24 displaced 120 tons and carried two 2cm guns and up to eight mines. In 1936 a similar, slightly smaller variant but with greater draft appeared, numbered R21 to R40. Both 1934 and 1936 types remained in production during the war. An even larger version displacing 165 tons was brought into service in 1942; more than 200 were ordered but only around 75 completed. This type had a heavier armament of one 3.7cm and two 2cm guns.
The dedication to duty of the men of the Sicherungsverbände is reflected by the fact that amongst their number were one winner of the coveted Oakleaves to the Knight’s Cross, four Knight’s Crosses of the Iron Cross, and 13 German Crosses in Gold. This vessel is Minesweeper M31 of the 5. Minensuchflottille, commanded by Oberleutnant zur See Erwin Leesten, who was awarded the German Cross in Gold on 9 August 1944. (Courtesy Stuart Schultz)
A typical Räumboot. These inshore motor minesweepers were similar in appearance to the early Schnellboote, and indeed manufactured by the same yards, but did not carry torpedoes and had only light armament. Note the T-shape of an eagle-and-swastika emblem below the bridge windows. (Author’s collection) displacement to 165 tons. (Deutsches U-Boot-Museum)
One interesting development of the R-boat arose from the need for small, shallow-draft vessels for use in the narrow fjords of occupied Norway. In October 1940 the officer commanding one unit, Kapitänleutnant Hans Bartels, commissioned the construction of his own highly successful small vessels based on Norwegian fishing boat designs. These 12 boats were called Zwerge (‘dwarves’) and were to become known as the ‘Tigerverband’, all vessels flying a pennant bearing a snarling tiger’s head over crossed swords. To foster unit morale Bartels even had a small commemorative pin made with this emblem, which was awarded with a special certificate to members of the unit.
Despite his success, higher command did not appreciate junior officers acting on their own initiative in this way, and Bartels found himself posted as first officer to the destroyer Z34.
Räumboote at sea in a heavy chop. These small boats could carry out a variety of duties including escort work, minesweeping and sub-chasing. Well over one hundred were built, in classes ranging from 43 tons displacement to 165 tons. (Deutsches U-Boot-Museum)
The R-boats were organized into 20 flotillas, based as follows:
| Flotilla | Location | Active |
| 1. R-Bootsflottille | Baltic/North Sea/Channel | 1939–47 |
| 2. R-Bootsflottille | North Sea/Channel | 1939–44 |
| 3. R-Bootsflottille | Baltic/North Sea/Channel/Black Sea | 1939–44 |
| 4. R-Bootsflottille | North Sea | 1940–45 |
| 5. R-Bootsflottille | Baltic/North Sea | 1939–45 |
| 6. R-Bootsflottille | Channel/Mediterranean/Adriatic | 1941–45 |
| 7. R-Bootsflottille | Channel/North Sea | 1940–46 |
| 8. R-Bootsflottille | North Sea/Channel | 1942–46 |
| 9. R-Bootsflottille | Channel | 1942–47 |
| 10. R-Bootsflottille | Channel | 1942–44 |
| 11. R-Bootsflottille | Channel | 1939–40, 1942–44 |
| 12. R–Bootsflottille | Channel/Adriatic/Aegean | 1942–45 |
| 13. R–Bootsflottille | North Sea | 1942–57 |
| 14. R–Bootsflottille | Channel/Baltic/North Sea | 1943–46 |
| 15. R-Bootsflottille | Baltic/North Sea | 1944–45 |
| 16. R-Bootsflottille | Norway | 1944–47 |
| 17. R-Bootsflottille | Baltic/Channel | 1944–47 |
| 21. R-Bootsflottille | Norway | 1943–46 |
| 25. R-Bootsflottille | North Sea | 1943–46 |
| 30. R-Bootsflottille | Black Sea | 1943–44 |
Vorpostenboote, literally ‘outpost boats’, was an all-encompassing term used for a wide variety of vessels used for patrol work, forming outer protective screens for convoys and guarding numerous smaller ports. These were primarily former whaling and fishing vessels, and included large numbers of so-called ‘booty ships’ confiscated or captured from defeated nations. So great was the number and variety of vessels used in these roles that when studying photographs of VP-boats it is difficult to find two that are identical.
These boats were organized in 33 Vorpostenbootflottillen, operating in the following areas:
| Area | Flotillas | Area | Flotillas |
| Baltic | 1, 3, 5, 7, 9, 11, 13, 15, 17 &19 | Denmark | 9, 10, 16, 18 &19 |
| North Sea | 2, 4, 6, 8, 10, 12, 14, 16, 18 &20 | Norway | 63, 64, 65, 66, 67 &68 |
| France | 2, 4, 6, 7, 15 &18 | Mediterranean | 70 |
| Holland | 8, 11, 13, 14 &20 |
As well as captured and requisitioned former civil vessels, a number of purpose-built types were constructed, based on civilian fishing boat designs, these being known for being extremely sturdy and seaworthy. Such vessels were designated as Kriegsfischcutter, and as well as patrol work they might be used for minesweeping and anti-submarine duties.
A flotilla of Räumboote tied up in port. Note the camouflage scheme, which was widely used even on the smallest vessels. The R-boats shown here are of the batch R218–R271, and all seem to have a unit emblem painted on the oblique-angled bridge plate ahead of the boat number, below a circular port. R244 seems to show this as a white angular shield bearing a dark vertical motif. (Deutsches U-Boot-Museum)
Although a small number of dedicated sub-chaser units (U-Bootsjagd Flottillen) were formed, the bulk of anti-submarine operations were carried out by a mixture of minesweepers and VP-boats rather than by vessels specifically designed as anti-submarine warships. It had originally been intended that a range of such purpose-built ships would be constructed, and specifications were drawn up. It was eventually decided, however, that given the size and specification of the proposed vessels, and the issues of shipyard availability and the need not to waste time and resources on unnecessary diversication, that the task of anti-submarine work could be undertaken by existing vessels, particularly the M35 minesweeper. With no specific type of purpose-built sub-chaser vessel, the term was used to describe any boat allocated to such duties.
| Flotilla | Location | Active |
| 1. UJ-Flottille | Black Sea/Baltic | 1943–44 |
| 2. UJ-Flottille | Adriatic | 1944 |
| 3. UJ-Flottille | Black Sea/Baltic | 1944 |
| 11. UJ-Flottille | Baltic/Norway | 1939–45 |
| 12. UJ-Flottille | North Sea | 1939–45 |
| 14. UJ-Flottille | Norway/France | 1940–45 |
| 17. UJ-Flottille | Norway | 1939–45 |
| 21. UJ-Flottille | Aegean | 1941–44 |
| 22. UJ-Flottille | Western Mediterranean | 1942–45 |
| 23. UJ-Flottille | Black Sea | 1944 |
Orders for the production of a new class of escort boat were given in March 1943. The new vessel was effectively to be a more powerful version of the R-boat with heavier armament including, significantly, torpedoes. The new vessel was intended to replace a number of other types such as R-boats and VP-boats. The result was a stylish, 290-ton boat, 52m long and with a 7.2m beam. A single 6-cylinder diesel engine would give it a speed of just 14 knots, sufficient for its role of escorting slower vessels. Armament consisted of 2x 8.8cm, one 3.7cm and eight 2cm flak guns. Two torpedo tubes were fitted, emerging from the hull near the bow in a somewhat similar manner to those on S-boats.
This shot clearly shows that the origins for the design of typical Vorpostenboote came from fishing boats. These smaller types were in fact also referred to as Kriegsfischkutter. (Deutsches U-Boot-Museum)
It was originally intended that 12 boats would be built by the Stülcken yard in Hamburg, but in the event only one was ever completed, MZ1. This boat was built in a conventional manner, but it was intended that future boats would be assembled from pre-fabricated sections. MZ1 was launched on 16 April 1944 and was well received. Had Germany’s military and industrial situation not been so bad by this date it is likely that significant numbers of this new type would have been constructed, but all that existed by the end of the war was MZ1 and the keels of three more partially constructed boats.
Records of MZ1’s use and eventual fate are virtually non-existent. It is believed that she was captured by British forces when Eckernförde fell, but there seems to be no record of what befell her.
The purpose of the Sperrbrecher, rather than to clear minefields, was to escort ships into and out of German-held ports along cleared paths through defensive minefield barriers, and to detonate any mines that might have been laid by the enemy in these clear paths.
Most Sperrbrecher began their lives as merchant vessels, and were crewed by merchant seamen with a small cadre of naval personnel. These were termed ‘Special Purpose Merchant Ships’ (Handelsdampfer zb V). Others were crewed entirely by naval personnel. Both German-built and captured foreign vessels were pressed into service as Sperrbrecher. It was typical for a Sperrbrecher to have its hold filled with buoyant material to help keep it afloat should it run into a mine, and for the bows to be significantly strengthened. Nevertheless the detonation of a powerful mine could easily break the back of a ship, so service on this type of vessel must have required strong nerves on the part of its crew. Photos of Sperrbrecher will often show a metal beam set just forward of the bow, intended to detonate any mine before it touched the hull itself.
Armament on Sperrbrecher varied; as they were never expected to engage enemy surface ships it tended to consist primarily of antiaircraft guns, but these might be numerous. Typical armament in the second half of the war might comprise 2x 10.5cm, 6x 3.7cm and 14x 2cm guns. In addition, many Sperrbrecher were equipped with barrage balloons.
A larger Vorpostenboot, this time in pale grey livery, with her main armament on a platform at the bow. Her ‘fishing trawler’ lines are still clear. (Deutsches U-Boot-Museum)
This interesting shot of a Sperrbrecher in harbour shows just how effective disruptive camouflage schemes could be. The use of the black German cross emblem on the side of the superstructure is most unusual on ships. (Author’s collection)
Barrier-breakers were organized into a total of seven Sperrbrecherflottillen, as follows; like the minesweepers, more than one unit remained in service after the war, making safe the waters around Europe’s coasts:
| Flotilla | Location | Active |
| 1. Sperrbrecherflottille | Baltic/German Bight | 1940–46 |
| 2. Sperrbrecherflottille | Channel/Bay of Biscay | 1939–44 |
| 3. Sperrbrecherflottille | Baltic | 1940–46 |
| 4. Sperrbrecherflottille | Channel | 1941–43 |
| 5. Sperrbrecherflottille | never operational; existed only 1 month | |
| 6. Sperrbrecherflottille | Bay of Biscay | 1941–44 |
| 8. Sperrbrecherflottille | North Sea/Channel | 1941–45 |
 |
1: Raumboot A typical R-boat from the batch numbered R73 to R88, manufactured in about 1941. These fast, manoeuvrable, shallow-draft boats became the ‘maids of all work’ among the Kriegsmarine’s coastal craft, but were predominantly used as escorts or inshore minesweepers. |
| 2: Vorpostenboot | |
| This is but one example of what appears to have been a myriad of variants of these ‘outpost boats’. One common feature is that almost all of the types used bore a strong resemblance to the basic design of a fishing boat, with a high forecastle (usually with a gun platform) and a relatively tall funnel. These robust little boats were capable of working in the roughest of seas. Many survived the war to take part in post-war mine clearing. | |
| 3: Flottenbegleiter | |
| Only ten examples were produced of this unsuccessful class of vessel; the illustration shows one of the first six, built at the Germaniawerft yard in Kiel. The remaining four, built by Blohm &Voss in Hamburg and the Kriegsmarine Werft in Wilhelmshaven, were very similar, but with marginally shorter funnels and a slightly different layout to the superstructure amidships. | |
| 4: German state yacht ‘Aviso Grille’ | |
| For a yacht Grille was powerfully armed. Her three 10.5cm gun turrets were supplemented by two twin 3.7cm flak mounts just aft of the funnel, as well as four single 2cm mounts. The rakish lines of Grille were seen at numerous naval regattas before the war, and she hosted many foreign dignitaries. Although she is often referred to as ‘Hitler’s’ yacht, in fact he rarely visited her. After the outbreak of war she served in numerous roles, including as a ‘target’ ship for training the crews of torpedo-carrying aircraft. |
A distinction must be drawn between improvized and purpose-built escorts. A class of fleet escorts (Flottenbegleiter) were planned and built, their pennant numbers being prefixed with ‘F’. However, only ten were ever constructed, as follows:
| Shipyard | Vessels | Total |
| Germaniawerft, Kiel | F1–F6 | 6 |
| Blohm &Voss, Hamburg | F7–8 | 2 |
| Kriegsmarinewerft, Wilhelmshaven | F9–10 | 2 |
| Specifications: | |||
| Length | 68m | Powerplant | 2x 14,000hp turbines |
| Beam | 8.7m | Top speed | 18 knots |
| Displacement | 870 tons | Endurance | 5,000 nautical miles |
| Armament | 1x 10.5cm gun, 1x 3.7cm flak, 4x 2cm flak; 4x depth charge launchers; up to 30 mines | Crew | 24 |
The first was launched in December 1935 and the last by March 1938. The principal purpose for which they were designed was to act as an inner escort screen for the ‘pocket battleships’ Deutschland, Admiral Graf Spee and Admiral Scheer. Due to technical problems with the type of high-pressure boilers installed in these vessels, they were not considered successful and no more were ordered. They were organized into two flotillas as follows:
| Flotilla | Vessels |
| 1. Geleitflottille | F1, 2, 5, 6, 9 &10 |
| 2. Geleitflottille | F3, 4, 7 &8 |
Due to their limitations, it was decided that these vessels could best be employed as minesweepers; but problems during exercises raised questions over their speed, manoeuvrability and endurance as well as the reliability of their engines, and led to the disbandment of 2. Geleitflottille. The Geleitboote were finally judged to be of so little effective value that even before the outbreak of war it was decided to delegate them to various non-combat duties, as follows:
| Flotilla | Duty |
| F1 | To be allocated as a command ship to Führer der Minensuchboote Ost |
| F2, F4 &F7 | To be converted into torpedo recovery vessels |
| F3 &F6 | To be converted into tenders, with most armament removed and extra accommodation added |
| F5, F8, F9 &F10 | To be allocated to the Anti-Submarine Warfare School as training vessels |
However, the outbreak of war in September 1939 put paid to these plans. Under wartime conditions the Navy had to make the best it could of these boats; but by December, F9 had been lost when torpedoed by a British submarine, and the others had performed so badly that the plan to remove them from operational service was revived. Any thoughts of trying to refit and improve these boats was quickly discarded as a waste of up dockyard time and resources.
Accordingly, F2, F5, F7, F8 and F10 were simply handed over to the U-boat arm for use as torpedo recovery vessels and submarine escorts. F1 was allocated to the Führer der Zerstörer as a tender/command vessel; F3, allocated to the Führer der Minensuchboote in the same role, was sunk by rocket-firing aircraft in May 1945. F4 served as a trials vessel with Sperrversuchskommando and Torpedoversuchsanhalt, but returned to minelaying in 1944. F6 took part in the attack on Norway, allocated to the Führer der Minensuchboote (West); she saw service in minelaying and escort duties throughout the war, eventually being sunk by Allied aircraft during an attack on Wilhelmshaven in April 1945.
Despite their serious limitations these ships were relatively fortunate in that six of the ten survived the war, and a number served on under the less demanding needs of peacetime; indeed, F7 served in the Soviet Navy until at least 1956.
Although these purpose-built Flottenbegleiter were a complete failure, the concept of allocating vessels into units specifically tasked with escort work survived them. In all seven flotillas were created, deployed operationally as follows:
| Flotilla | Location | Active |
| 1. Geleitflottille (reformed) | Adriatic | 1944–45 |
| 2. Geleitflottille (reformed) | Adriatic | 1944–45 |
| 3. Geleitflottille | Mediterranean | 1943–44 |
| 4. Geleitflottille | Mediterranean | 1943–44 |
| 5. Geleitflottille | Baltic | 1945 |
| 30. Geleitflottille | Black Sea | 1943–44 |
| 31. Geleitflottille | Black Sea | 1942–44 |
Additional small units under the control of the Sicherungsverbände included:
Netzsperrverband Units that maintained the boom defence nets around German ports and naval bases. The vessels were classed as Netzleger (netlayers) and Netztender. The flotillas into which these units were formed were designated by area rather than number, i.e. Netzsperrflottille Nord.
Hafenschutzflottillen Harbour protection flotillas were generally formed of small craft such as armed trawlers and armed tugboats and, as the name suggests, were permanently based in ports to protect the installations. There were three such flotillas based in major German naval bases: Hafenschutzflottille Cuxhaven, Hafenschutzflottille Wilhelmshaven and Hafenschutzflottille Borkum.
At the end of hostilities in May 1945 huge amounts of work remained to be done in clearing mines from European coastal waters.
A large number of Kriegsmarine personnel remained in service between August 1945 and December 1947, in the Deutsche Minenräumdienstleitung (German Mine Sweeping Administration, GMSA), continuing to wear their Kriegsmarine uniforms and insignia – though of course with the swastikas removed. This organization was under British control; although many personnel were issued new GMSA paybooks, a large number of original Third Reich-period issued books continued in use, and examples may be found with Royal Navy entries.
A Geleitboot or ‘Flottenbegleiter’. While appearing quite sleek and purposeful, this small class of F-boats was far from successful; repeated problems with the turbines saw them relegated to second-line duties. (Author’s collection)
From January 1948, German minesweeping activities passed to the Deutsche Minenräumverband based in Cuxhaven. This comprised around 45 officers and just over 500 men, all of whom were volunteers, under the ultimate authority of the Allied Control Commission. These men cleared mines from coastal waters until June 1951 and the creation of the Seegrenzschutz (Sea Border Defence service), which led ultimately to the foundation of the Bundesmarine (Federal German Navy).
The minesweeping service therefore presents a unique situation, in which a German sailor might have virtually unbroken sea service from the days of the Kriegsmarine through to the Federal Navy of West Germany.