U-boat War

Type II U-Boats

The Type IIC U61 is removed from the water at Lorient along the French slipway, 16th September 1940 - in the background a fishing vessel undergoes conversion to become a member of the Lorient Hafenschutzflottille.

TYPE IIA

Dimensions: 40.9 metres x 4.1 metres x 3.8 metres (draught)

Displacement: 254-tonnes (303 -tonnes dived) Complement: 3 officers, 22 crew.

Rated Diving Depth: 250 feet.

Armament: 3 x 53.3cm (21”) torpedo tubes at bow below the designed waterline.
5 x torpedoes or 12 TMA (18 TMB) mines.
1 x 2cm/30 AA cannon (1200 rounds) on a detachable deck mounting.

Propulsion: 2 x MWM RS 127 S 6-cylinder 4-stroke 350 horsepower supercharged diesels, in compartment two. 2 x SSW PG VV 332/36 double commutator- type 205 horsepower electric motors in compartment one. 1 x 62-cell AFA 36 MAK 580 battery in battery boxes without rubber shock absorbers (7160 amp hours) or 1 x 62-cell AFA 44 ML 570 battery (8380amp hours).

Speed: 13 knots surfaced/7.4 submerged.

Range: 1,600 miles @ 8 knots/ 35 miles @ 4 knots (submerged)

TYPE IIB

Dimensions: 42.7 metres x 4.1 metres x 3.8 metres (draught)

Displacement: 279-tonnes (329 -tonnes dived) Complement: 3 officers, 22 crew.

Rated Diving Depth: 330 feet.

Armament: 3 x 53.3cm (21”) torpedo tubes at bow below the designed waterline.
5 x torpedoes or 12 TMA (18 TMB) mines.
1 x 2cm/30 AA cannon (1200 rounds) on a detachable deck mounting.

Speed: 13 knots surfaced / 7 submerged.

Range: 3,100 miles @ 8 knots / 40miles @ 4 knots (submerged)

TYPE IIC

Dimensions: 43.9 metres x 4.2 metres x 3.8 metres (draught)

Displacement: 291-tonnes (341 -tonnes dived) Complement: 3 officers, 22 crew.

Rated Diving Depth: 330 feet.

Armament: 3 x 53.3cm (21”) torpedo tubes at bow below the designed waterline.
5 x torpedoes or 12 TMA (18 TMB) mines.
1 x 2cm/30 AA cannon (1200 rounds) on a detachable deck mounting.

Speed: 13 knots surfaced/7.4 submerged.

Range: 3,800 miles @ 8 knots / 40miles @ 4 knots (submerged)

TYPE IID

Dimensions: 44 metres x 4.1 metres x 3.9 metres (draught)

Displacement: 250-tonnes (364 -tonnes dived) Complement: 3 officers, 22 crew.

Rated Diving Depth: 330 feet.

Armament: 3 x 53.3cm (21”) torpedo tubes at bow below the designed waterline.
5 x torpedoes or 12 TMA (18 TMB) mines.
1 x 2cm/30 AA cannon (1200 rounds) on a detachable deck mounting.

Speed: 12.7 knots surfaced / 7.4 submerged.

Range: 5,650 miles @ 8 knots / 56miles @ 4 knots (submerged)

The small single hull (i.e. the outer skin of the submarine is the pressure hull with supporting frames inside) Type II A-D U-boats were laid down as coastal submersibles, based on a combination of the 1933 redesign of 1918 Type UF submarines, the First World War UBII Class and aspects of the Finnish/German Vessikko model. Models A and B possessed a single periscope, while C and D incorporated a second attack periscope housed within the tiny conning tower. Comprising three watertight compartments within the single hull, diving tanks were located in the bottom of compartment two while trim tanks lay in compartments one and three. The fuel oil bunker in turn was immediately aft of the trim tanks. A major advance in German design work meant that U-boats had welded pressure hulls instead of weaker rivets. This pressure hull eventually had a maximum rated diving depth of 150 metres, well over contemporary standards. Two 3-bladed propellers of 85cm diameter pushed the single ruddered U-boat. For vertical manoeuvring they were equipped with two hydroplanes forward and two aft. The main obvious physical difference between the various marks was found in the arrangement of flooding slots along the hull sides.

In all, 50 such submarines were constructed. They were not ideal for operational use, unstable in moderate to heavy seas and capable of only low surface speed and limited endurance. Only by utilising newly captured French ports during 1940 were these small U-boats able to contribute to the Atlantic war, in which conditions the limitations of the boats became all too apparent. Living and working conditions aboard were primitive in the extreme for the crew, the internal space having no real subdivision.

“They were fast to dive - the same as a Type VII. But there was not much room, I had not even a special part for the commanding officer, I was sleeping in the bow room where all the torpedoes were, and I had no privileges on board.” (Erich Topp interview 27th April 2001).

Moreover, in order to conform to the rulebook of submarine warfare, U-boats were initially compelled to surface and fire a warning shot over the bow of any merchant shipping intercepted. The idea of firing a burst of 2cm cannon fire in order to intimidate a large cargo vessel must have appeared faintly ridiculous to many commanders and crew.

However despite these facts many of the Kriegsmarine's "Aces" began their combat service as commanders aboard these small boats scoring many notable successes: Otto Kretschmer, Erich Topp, Adalbert Schnee, Wolfgang Lüth, Claus Korth and Herbert Wohlfarth to name but a few. Also the small Type II boats comprised the "Black Sea Flotilla" (30th U-Flotilla) that took the war into the virtually landlocked Black Sea against Russian Naval forces.