u-47

U-47: Build Details and Technical Specifications

The following information covers the basic technical specifications of the Type VIIB U-boat in general, and U-47 in particular.

A. Build Details

Type: VIIB
Works: Krupp Germaniawerft, Kiel
Series: U45 - U55
Build Commissioned: 21.11.1936
Build Number: 538
Completed: 25.02.1937
First Launch: 29.10.1938
Handed over for Service: 17.12.1938
Field Post Number: 18837

B. Technical Specifications

A side view of the Type VIIB U-Boat. The torpedo tubes are indicated in red.

Displacement:

Washington 517 metric tons
Surfaced (dry) 704 metric tons
Surfaced (fuel and water tanks full) 753 metric tons
Submerged 857 metric tons
Submerged (fully crewed and loaded) 1040 tons

Length:

Casing 66.5m (218.2')
Pressure hull 48.8m (160.1')

Beam:

Casing 6.2m (20.3')
Pressure hull 4.7m (15.4')

Draught:

4.7m (15.4')

Height:

9.5m (31.6')

Engines:

Two Germaniawerft 6-cylinder 4-stroke F46 diesels with superchargers totalling 2800 - 3200bhp

Motors:

Two AEG GU 460/8-276 electric motors totalling 750shp

Batteries:

Two rooms with 62 lead-acid AFA 27 MAK 800 battery cells producing 7500 amp hours

Fuel oil:

Maximum 108.3 metric tons
Normal load 99.7 metric tons (57.3 tons within pressure hull)

Speed:

Surfaced 17.2-17.9 knots
Submerged 8.0 knots

Range (surfaced):

3850nm at 17.2 knots
6500nm at 12 knots
8700nm at 10 knots
combined diesel/electric drive range 9400nm

Range (submerged):

90nm at 4 knots

Diving depth:

Operational - 100m (328')
Crush - 200m (656')
Maximum sustainable depth - c. 220m (733.3')

Diving time

30 seconds

Periscopes:

Sky - Standserohr C/2 with fixed eyepiece
Attack and night - Binokulare Nacht-Luftziel-Seerohr(NLSR)

Hydrophones:

Gruppenhorchgerat (GHG) (fixed hydrophone array) - 11 hydrophones per side, above forward dive planes

UWT:

Two underwater telephone membranes fitted on either side, above GHG (one for transmission and one for receipt of sound waves)

Armament:
» more info

88mm deck gun
20mm Flak gun

Torpedo tubes:

Bow - 4 x 21" (53.3cm) tubes
Stern - 1 x 21" (53.3cm) tube

Torpedo types:
» more info

G7a compressed air torpedo
G7e wakeless torpedo

Torpedo numbers:

Forward tubes - 4
Forward torpedo compartment - 6
Aft tube - 1
Aft torpedo compartment - 1
Between pressure hull and forward deck casing - 1
Between pressure hull and aft deck casing - 1
Total - 14. NB. Space was allocated in the deck casing for two additional torpedoes - one in the forward deck casing and one in the aft deck casing.

Mines
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26 x TMA or 39 x TMB

Boats

1 dinghy, stored under forward casing forward of the torpedo loading hatch

Crew

December 1938 - 39
October 1939 - 40
February 1941 - 44