Kriegsmarine torpedo designation system
The first letter indicates the diameter:
Contents
- Kriegsmarine torpedo designation system
- Warheads and pistols
- Code names
- Program steering
- Luftwaffe lufttorpedo designation system
- Bombentorpedoes
- Kriegsmarine
- Luftwaffe
- References
The number indicates the approximate length (for example, the length of a G7a is 7163 mm):
Next letter(s) indicates specific features regarding propulsion and control:
"r" and "t" were only used with "u" to further denote the features of the ingolin-torpedoes. Some sources claim that "s" only was used with "a" to denote the development of G7a with acoustic seeker-capability; however, it was no doubt used for the electric torpedoes with acoustic seekers (as "es" or just "s").
When the torpedo reached production status and was fielded (i.e. for operational use), Kriegsmarine gave it a short designation "T", or "Torpedonummer", with the number given in Roman lettering (TI, TII, TIII, TIV etc.). For different versions of the main torpedo, a small Arabic letter was added (for example TIIId, TVa etc.) denoting specific/minor changes within the main design.
Warheads and pistols
Warheads was designated with the letter "K" (K = short for Kopf, meaning "head") and a small Arabic letter, with an additional number denoting variants of the head (variations was typical the change of material from bronze to steel, adding/removing spants during the course of the war and method of installing the explosives). Examples: Ka, Ka1, Kb, Kb1 etc.
Pistols used the "Pi" designations to begin with (Pi = short for pistole). The early models was named according to function and/or torpedo type like "PiG7H" or "PiG7a-MZ", but this was later replaced by a simple system of numbers, like "Pi1", "Pi2" etc.
To indicate variants within the main design, a small Latin letter was added after the number, like "Pi1a", "Pi1b" etc.
At some point, "Pi" was dropped for pistols with combination of mechanical (direct hit) and magnetic (distance-sensor) mechanisms, to the "TZ" designation (TZ = Torpedo-Zündeinrichtung). For example, the mechanical mechanism from the "Pi1" pistol combined with the magnetic mechanism from "Pi2" became the "TZ2".
Code names
Code names were intended used only through the development period for security measures. However, in some cases it was kept on also after the torpedo was fielded and designated with the "T"-number.
Torpedo pistols, program seeker-systems and other special arrangements also had their own "system" of code names, using the names of birds, fish or animals (for example Pi "Leuchtfisch", GA "Specht", seeker "Storch", control "Viper", target detector "Salamander" etc.). During development, the pistols often got code names designated by the industrial developer or manufacturer like simple words/syllables or names associated with the firm or the engineers in charge of the development (for example Pi "Otto", Pi "Atlas", Pi "Berlin" etc.).
Program steering
The program steering consisted of a mechanical construction coupled to the gyroscope, which changed the torpedo's course over time in different patterns, after an initial straight running distance.
Fat I ("S-shaped" loop-patterns): The initial straight distance could be set from a minimum of 500 m to a maximum of 1500 m. Two loop-patterns available: "short" and "long", and in addition there were a choice of right or left turns (i.e. a total of 5 settings on the Fat-mechanism). For "short" loops, the straight distance between turns was 800 m, with a total width of the pattern-search of 1140 m For "long" loops, the straight distance between turns was 1500 m, and a total width of the pattern-search of 1840 m. The turning radius for both patterns were 170 m.
Fat II ("S-shaped loops or circular patterns): The same data as for Fat Il, but an additional choice for "circular" pattern, where the torpedo would run in a circle after the initial straight-run. This was an option primary used by uboats against attacking surface-ships that ran a zig-zag pattern hunting the u-boat (the goal was to locate the torpedo's circle-run just ahead of the attacking ship, hoping for a "lucky" hit).
Fat III / Lut I ("zig-zag" pattern): Initial torpedo course can be chosen, so the torpedo platform don't need to change its bearing to an optimal course for torpedo launch. The "Lut-speed" (i.e. the resulting advance-speed of the torpedo, considering the zig-zag pattern) can be chosen, and subsequently the straight legs between turns will be adjusted accordingly.
Lut II: Same as Lut I, but even slower Lut-speeds could be chosen.
Luftwaffe lufttorpedo designation system
As a general rule, Luftwaffe followed the Kriegsmarine system of code names and designations, but with some differences.
Variations for the letter(s) indicating specific features regarding propulsion and control:
Instead of letters and numbers denoting dimensions and features, a single 3 or 4 digit number was used for some torpedo designs.
Luftwaffe also used the "LT" designation (= Lufttorpedo), but not limited to operational torpedoes. It also combined further letters and numbers to indicate type and features of the torpedo:
Designations for Luftwaffe pistols used the same system as Kriegsmarine, while the warheads used the designation GK (GK = short for Gefechtskopf) followed by a number and a small Arabic letter for variants.
Bombentorpedoes
Luftwaffe also developed a passive weapon called "Bombentorpedo" (BT), which was planned to replace the conventional torpedoes. It was airdropped from a low height and relative short distance from the target, would enter the water and travel the short remaining distance through the water solely driven by its kinetic energy. No BT's were ever fielded operationally.