G7a Torpedo - Technical Data For G7a TI

Technical Data For G7a TI

• Type: Standard, straightrunning torpedo with wet-heater propulsion and whitehead tail
• Design: Ca. 1930
• Operative service in Kriegsmarine: 1938-1945 1)
• Length (prepared for launch with warhead): 7163mm
• Diametre: 533.4mm (21")
• Weight (prepared for launch with warhead): 1538kg
• Charge, warhead: Ca. 280kg Hexite
• Boostercharge (Pi1 pistol): 300g Pentrite
• Minimum angle of impact to detonate (Pi1 pistol, mechanical mode): 16 degrees
• Speed: 30kn ("Weitschuß", WS) / 40kn ("Nahschuß", NS) / 44kn ("Schnellschuß", SS) 2)
• Depthsetting: 1-12m (TA-I), 1-15m (TA-II)
• Armingdistance (Pi1 pistol): 100m (black impeller) / 150m (red impeller) / 300m (blue impeller) 3)
• Propulsion: 4-cylinder steam engine (powered by a mixture of overheated steam and compressed air)
• Fuel: Decaline
• Power output, engine: 110Hp (30kn) / 255Hp (40kn) / 350Hp (44kn)
• Engine RPM: 1170 (30kn) / 1280 (40kn) / 1470 (44kn)
• Propeller: 2 x 6-blade (contra-rotating) 4)
• Max running distance: 12000m (30kn) / 7500m (40kn) / 5000m (44kn)
• Capacity, air-tank: 676l (200kg/cm^2)
• Freshwatercompartment: 57l
• Fueltank: 14,5l
• Oiltank (engine): 6,5l
• Oiltank (low-pressure regulator): 0,3l
• Steering: Mechanical gyroscope powered by pressurized air (GA VIII) with anglesetting mechanism (+/- 90 degrees from initial course after launch)
• Depthcontrol: Hydrostatisc mechanism with pendulum (TA-I or TA-II)

1) Used in post-war service by several navies with different modifications and designations (Bundesmarine: DM11, Royal Danish Navy: T1T, Royal Norwegian Navy: T1 mod 1). Last known operator was RNoN with the T1 mod 1 (G7a with wire-guidance: Although 4 modifications to the torpedo where carried out over the years - the last with computerized control in 1992 - the same designation "mod 1" was applied throughout its service). T1 mod 1 was used from FAC's (until 1992), submarines (the 80's) and Coastal artillery shore-batteries (1999). 2) 44kn was to be used by S-Boote (problems with initial design lead to breakdown on motors running 44kn, so this setting was banned until the new engine was available) 3) Black used only from shore torpedobatteries, red from surfacevessels and blue from submarines 4) Early versions had 4-blade propellers

Other versions:

• TI Fat I: TI with Fat I programsteering 1)
• TI Lut I: TI with Lut I programsteering 1)
• TI Lut II: TI with Lut II programsteering 1)
• TIü: TI dedicated training for Schulboote at U-Flotillen (only used with exercise head and equipped with the older-type depth mechanism)
• TIü Lut II: TIü with Lut II 2)
• TXIV: TI with changed buoyancy (max airpressure reduced from 200 to 100kg/cm^2) for the Seehund midget submarine. With sinker-mechanism.

1) For launch with program setting, speed could only be set to 30kn 2) For launch with program setting, speed could be set to 30 or 40kn

Exercise- and Warheads/pistols used on the TI:

Exersiceheads:

• Type 1210 or type 1215 (improved head with dual blow-mechanisms)

Warhead/pistol statutory combinations according to Kriegsmarine regulations:

• Ka, Ka1 or Ka2 with Pi1, Pi1a or Pi1c pistols
• Kc with Pi3 or Pi3c pistols
• Kc1 or Kc2 with Pi3, Pi3a or Pi3c pistols

Warhead/pistol possible (technically) combinations - only on special demand, approved by torpedo-arsenal and with special consideration to depth-settings in order to assure proper function of the pistol:

• Kb or Kb1 with Pi1, Pi1a, Pi1c, Pi2*, Pi2c* or Pi2c* pistols (* only heads with extended pocket)