Flottenbegleiter (F class Escorts)

The Flottenbegleiter were a multi-purpose class of ten specialized escort vessels built for the Kriegsmarine in the late interwar. However they certainly were probably the worst ships of the Kriegsmarine, hand down. During the Second World War between poor reliability and seakeeping despite modifications had them relegated to second-line duties in the Baltic Sea. Four ships were sunk during the war and the survivors were scrapped afterwards after very little actual service. With the exception of a few convoy duty missions between 1939 and 1941, they spent most of the war in use as tenders or U-boat training ships. Between 1943 and 1945, escort ships were grouped into five escort flotillas, augmented by converted civilian vessels, or captured torpedo boats of the Torpedoboot Ausland program.

One ship, F 9, was sunk in December 1939 after being torpedoed by HMS Ursula. F 5 was damaged by a mine in the Baltic Sea and sank under tow on 29 January 1945. F 3 was sunk by British aircraft on 3 May 1945 and F 6 was sunk by US aircraft 30 March 1945. The others survived the war and were scrapped or sunk as target ships.

Development

In 1933 when Hitler came to power and decided to rearm, the Kriegsmarine, successor of the Reichsmarine, was concerned, but the global tonnage was still limited by the Washington Treaty. With the 1935 Anglo-German naval treaty in the wake of Britain’s appeasement policy, these limitations went by the window. Now the Kriegsmarine was limited to 35% of the Royal Navy tonnage AND by the Washington treaty. In the latter many loophole were quickly exploited by future axis nations, notably that below 600 tonnes standard there was no limitation in the number of warships to be built, provided it stayed wirhing the global authorized tonnage. This was exploited to build a new generation of torpedo boats, a type discarded before WWI as proper destroyers seems much more useful.

The advantage of building torpedo boats en masse, below that 600 tonnes standard limit (cheated or not) was to free destroyers for fleet escort (ie. escorting cruisers or capital ships), leaving less important ships, auxiliaries and transports, to torpedo boats. However the OKM, Oberkommando der Marine, defined in 1934 already a type of ship that would even free torpedo boats in turn for more offensive missions for the fleet. These escort vessels needed to have sufficient range, but speed, unlike TBs, was moderate, adapted to convoy pace, they would not have torpedoes, but concentrate on artillery, antiship and AA, just as gunboats. Hence was born the The Fleet Escort or “Flottenbegleiter”.

When designed in 1934 this was the only class of purely escort vessel of the German Navy built in series. These Fleet Escorts were built to escort supply convoys, but they were also capable of laying and clearing minefields. They were planned as jacks of all trades, fast escort ships but also as fast mine-sweepers and submarine hunter. But they were also testbeds for new high-pressure destroyer engines, all awaited of a small anc cheap design. Indeed, eventually, in their original form, thse ships did not prove particularly effective due to several factors starting by poor seaworthiness. For this reason, they were rebuilt and, in some cases, lengthened at the Wilhelmshaven Naval Shipyard between 1938 and 1940. But this did not cured their illness.

The class consisted of ten boats, F 1 to F 10. F 1 to F 6 were built between 1934 and 1936 at the Germaniawerft shipyard in Kiel, F 7 and F 8 between 1935 and 1937 at Blohm & Voss in Hamburg, and F 9 and F 10 from 1934 to 1938 at the Kriegsmarine shipyard in Wilhelmshaven. Due to the short design time, the boats were poorly conceived and proved to be a flawed design. Particularly because they were used as testbeds for the new Wagner boilers, lengthy shipyard stays resulted, as systems ready for frontline service were retrofitted.

In addition, there was the Escort 1941 class or the “Schnelle Flottenbegleiter”, a completely new design based on the unbuilt Gunboat 1938 type, but this was cancelled due to a shift in priorities after the completion of the lead vessel. Also among the unrealized projects was the boat officially designated as a multi-purpose vessel, MZ 1. However instead the Kriegsmarine for the same mission had to rely on torpedo boats captured in their 1940 campaign, from France, the Netherlands or Norway, in the “Torpedoboot Ausland program”.

Design of the class

The ships were built by Germaniawerft (F 1 – F 6), Kiel, Blohm & Voss (F 7, F 8) and Wilhelmshaven dockyard (F 9, F 10). They entered service between 1936 and 1939. Similar in size to the Type 35 and Type 37 torpedo-boats, the ships were originally conceived as fast fleet or convoy escort ships that could also perform anti-submarine and minesweeping work. They were also used as a test bed class for a new high-pressure steam power plant intended for use in destroyers.

As a class, they were overloaded and over-engined, which contributed to severe hull stress and very poor sea-keeping characteristics; these flaws were partially remedied by extensive rebuilds between 1938 and 1940. The power plants likewise proved to be prone to frequent breakdowns, and most of the ships were removed from operational service during the later years of the war after machinery failures meant the ships spent more time in repair than in use.

Hull and general design

The ships’s initial displacement as planned was 712 t (701 long tons) standard and 1028 t (then 1,147 t after modifications in 1940) fully loaded. This was sitll 100 tonnes above the tolerated Washington limit for an overall lenght of 75,94 m (249 ft 2 in) originally, then ported to 80,20m after reconstruction, for a waterline lenght of 73,50 m also ported to 74,80 m to improve seaworthiness. The original beam was 8.80 m (28 ft 10 in), unchanged, as well as its draught of 3.24 m (10 ft 8 in).

Design-wise they shared little commonality with the torpedo boats of the 1st generation (Type 1935), and more with the Type 23-24. They had a two-staged hull with a forecastle ending at the bridge’s end, a low aft deck ending in a semi-transom stern, two funnels, raked, capped and heavenly spaced. The bridge combined a blocky base beam-wide, with an open deck, and the enclosed deck with a rounded face embedded in it, topped by an observation deck, a telemeter and a pole mast onto which was attached a searchlight platform abd a spotting top. There was a small mast aft just to received wireless radio cables, and a small boom aft amidship.

The superstructure was more generous than a contemporary torpedo boat due to the absence of torpedo tubes, and the AA mounts were installed on sponsoned platforms on top. Overall, they looks right, even aesthetically pleasing, but shared the same almost straight prow and lack of flare of contemporarry German designs, that doomed their seaworthiness. Their construction called for standard steel and they had no protection apart compertimentation below the waterline. The crew amounted to 121 and they had four service boats fore and aft, including two motor cutters.

Powerplant

That was the stinging part. Officially they were test beds for future destroyer machinery. They were fitted with two shafts and associated geared steam turbines fed by two boilers for a total of 10,000 kW (14,000 shp) and a top speed of 28 knots (52 km/h; 32 mph). The high-pressure Wagner boilers were all the rage at the time, and they had been installed as well on the new Type 1935 torpedo boats, resulting in the same issues on the long run. The turbines were also prone to frequent breakdowns. Although repairs were done time and again, this severely reduced their active service, with more time spent at berth than at sea.

But when they worked, at sea, captains noted very soon freightening groans of the hull that denoted poor rigidity. The hull not only lacked seaworthiness, as the prow was constantly flooded even in moderate seas, and stiffering was necessary. Thus, they all had extensive rebuilds between 1938 and 1940. Top speed in the best conditions was 28 knots, but in heavy weather this fell to below 20 knots at the best of times, and their radius of action based on a fuel bunkerage of 216 tonnes of fuel oil was 1500 nautical miles at 20 knots.

Armament

The F-class escorts had two 105mm/42 SK C/32 one on the forecastle, the other on the aft deck, under masks, and two twin 37mm/80 SK C/30 AA mounts, then four single 20mm/65 FLAK C/30 for AA defence, and against submarines, four depht charge racks (DCR) for 36 depht charges total. They also had railed for mines, between 50 and 62, albeit it seems they never were used as minelayers.

105mm/42 SK C/32

Under masks, shared by the Type 1924 and Type 1935 torpedo boats.
Weight and size: 1,585–1,785 kgs (3,494–3,935 lb), 4.74–4.86 meters (15 ft 7 in – 15 ft 11 in)
Elevation: -10° to +50° on mount MPLC/32.
Shell: 15.1-kilogram (33 lb)
Muzzle velocity: 785 m/s (2,580 ft/s)
Range: 15,175 meters (16,596 yd) at 44.4°.
100 shells were provisioned.

37mm/80 SK C/30

Maximum elevation: +80°, Ceiling: 6,800 metres (22,300 ft). Range: 8,500 metres (9,300 yd)/35.7°.
Shell: 0.748-kilogram (1.65 lb), Muzzle velocity: 1,000 m/s (3,300 ft/s), Rate of fire: 30 rounds per minute.

20mm/65 FLAK C/30

Two 2-cm (0.8 in) C/30 anti-aircraft guns were installed individual posts in the bridge wings forward. Each boat carried 2,000 rounds per gun.
Weight and size: 450 kg (990 lb), 4.08 m (13 ft 5 in).
Rate of fire: 120 rounds per minute practical, 280 cyclic.
Shell: 0.12-kilogram (0.26 lb) HE, muzzle velocity 875 m/s (2,870 ft/s)
Ceiling: 3,700 meters (12,100 ft)
Range: 4,800 meters (5,200 yd).

Depth Charges

Rheinmetall 606 lbs. (275 kg), initial velocity of 115 fps (35 mps).
As for mines, they could carry the Type 23/24, EMC Contact Mines, placed on trolley rails. Spherical mines, 44 inch (1.12 m) in diameter. Charge 661 lbs. (300 kg). 7 Hertz horns. Could be moored in 55, 109, 164 or 273 fathoms (100, 200, 300 or 500 m).

Sensors

No radars but at least a baseline GHG hydrophone for basic ASW detection. The GHG was quite a primitive hydrophone, only accurate at short range, active, and at moderate speeds. The later Balcongerät was infintely more efficient (passive sonar).

⚙ specifications
Displacement	712 t (701 long tons) standard
Dimensions	75.94 x 8.8 x 3.24 (249 ft 2 in x 28 ft 10 in x 10 ft 8 in)
Propulsion	2 shafts geared steam turbines, 2 boilers 10,000 kW (14,000 shp)
Speed	28 knots (52 km/h; 32 mph)
Range
Armament	2× 10.5 cm (4.1 in), 2×2 3.7 cm (1.5 in) AA, 2× 2 cm AA
Crew	121

Career of the F class escort ships

From a postcard, before reconstruction.

Since they were technically inadequate for their intended use, the remaining nine boats were withdrawn from the front in the early stages of the war and converted into tenders or torpedo recovery vessels. Thus, the even older large torpedo boats and converted minesweepers, now designated as mine warfare vessels, had to replace this class. Due to numerous technical deficiencies, these fleet escorts saw little combat use. Although they achieved higher speeds than most other destroyer escorts, their lack of torpedo tubes and poor anti-aircraft armament meant they were not comparable to a destroyer escort of, for example, the Buckley class. After being recommissioned as tenders or torpedo recovery vessels, they were used for training purposes. Their task was now to retrieve the practice torpedoes fired by trainee submarine officers along the Baltic coast.

One was claimed to be the sunk in Tobruk Harbour by Native Military Corps Lance Corporal Job Maseko on July 21 1942, as a POW consigned to work as stevedore by the occupying Axis forces, for which he was eventually awarded the Military Medal, however none of this class were in the Mediterranean.

F 1 was laid down at Germaniawerft, Kiel, on August 2, 1934 and launched on March 1, 1935, completed in December. Given her poor performances after commission she was Converted to a tender right after by December 15, 1935, renamed Jagd (hunting vessel) in April 1942. She then received further modifications notably a full hull flush deck and became in 1941 the depot ship Libelle from May when recomissioned. In 1945, se was captured by the US and ended as war reparation, but was soon transferred back to the German Mine Sweeping Administration to serve until 1947, then handed over to France and scrapped afterwards .

F 2 was laid down on 7 August 1934, launched on 2 April 1935 and commissioned on 27 February 1936. Again, her sea trials revealed many issues and she was completely rebuilt from 6 April 1939 to 22 May 1940. She likely made a few escort missions but was barely active and her crew reassigned to other ships, she ended as war repearation for the British after May 1945, parked in Scapa Flow when she sank in a storm in 1946. She was partially recovered, later while the remaining hulk is still still a popular tourist diving destination today.

F 3, was laid down on August 22, 1934, launched on 1.6.1935 and commissioned on 3.1936 but converted into a tender in Königsberg and renamed Hai. She became flagship, minsweeper flottilla öst commander, and in this capacity she led the minesweeping suadron in April 1940 for the occupation of Norway through minefields of the Great Belt, and Kattegat.
She was sunk on May 3, 1945, by a British air attack in Kiel Bay. Her wreck was raised and scrapped in 1948.

F 4 was laid down at Germaniawerft on 2 July 1935, launched on 5 April 1936 and she was immediately converted as a tender with the name “Koblenz” planned, but it seems conversion was never completed and she laid mothballed and inactive until 1945 when she became a British war reparation, later scrapped.

F 5 was laid down at Germaniawerft on 6 September 1934, launched on 14 August 1935 and commission on 1 May 1936. Her combat records are unknown. She was semi-active until sunk on 29 January 1945 after striking a mine in the central Baltic Sea.

F 6 was laid down at Germaniawerft on 6 September 1934, launched on October 1, 1935, and rebuilt on June 25, 1936, converted into a fleet tender in 1938/39. She was recommissioned on September 20, 1939, under the new name of KMS Königin Luise (Queen Louise). She became a flagship or escort vessel for several units and by October 5, 1943, due to frequent machinery breakdowns, she was decommissioned in Nantes, French W Coast, transferred back to Wilhelmshaven. She was then motballed with a small care crew until sunk by a British air raid on March 30, 1945. The wreck was raised and scrapped in 1955.

F 7 was laid down at Blohm & Voss, Hamburg 10 January 1935, launced on 25 May 1936 and commissioned on 15 February 1937. No combat logs. She was still extant in 1945, given to USSR as war reparation in 1946 and likely scrapped after a few years.

F 8 was laid down at Blohm & Voss on 29 January 1935, launched on 27 July 1936 and commissioned on 8 April 1937. No combat records. In 1945 she was given as war reparation to the US, but scrapped in the Netherlands in 1950.

F 9 was laid down at Kriegsmarinewerft Wilhelmshaven on November 12, 1934, launched on May 11, 1936 and commissioned on August 21, 1937. She was sunk on December 14, 1939, by the British submarine HMS Ursula with two torpedoes off Heligoland. She sank in less than 30 seconds; there were only 15 survivors.

F 10 was laid down on 11 May 1936 at Wilhelmhaven on 12 March 1938, launched on 11 May 1936 and commissioned on March 1938. Like her sister she was found abysmal and she was not rebuilt but converted as a torpedo recovery vessel for training, helding this role wth a small crew until the end of the war. After 1945 she was given to the US as war remaration and scrapped in the Netherlands in 1950.

Read More/Src

Books

Campbell, John (1985). Naval Weapons of World War II. Annapolis, Maryland: Naval Institute Press.
Gröner, Erich (1990). German Warships 1815–1945: Major Surface Warships. Vol. I. Annapolis, Maryland: Naval Institute Press.
Rohwer, Jürgen (2005). Chronology of the War at Sea 1939–1945: The Naval History of World War Two (3rd rev. ed.). Annapolis, Maryland: Naval Institute Press.
Sieche, Erwin (1980). “Germany”. In Chesneau, Roger (ed.). Conway’s All the World’s Fighting Ships 1922–1946. London: Conway Maritime Press. pp. 218–254.
Whitley, Mike (1988). “F Boote of the Kriegsmarine”. In Grant, Ian (ed.). Warship 45. London: Conway Maritime Press. pp. 16–22.

Links

historyofwar.org
naval-history.net
facebook.com
ww2db.com
german-navy.de
navypedia.org
commons.wikimedia.org
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Model Kits

klueser.de

3D

subsim.com