[derstosstrupp]

Spreads are an interesting subject when it comes to games vs reality. There’s actually currently no U-boat simulation that gets the German spread correct. Whereas the Americans regarded their spread as covering generally the length of the target (which is what U-boat games also assume), the Germans thought of spreads as spreading torpedoes potentially multiple lengths of a target worth of dispersion. The Germans goal for a spread was to ensure one hit. If they intended to hit multiple torpedoes on one target they would fire what they called “multiple shots” (a “Mehrfachschuss”) simply just shifting the aim point and firing at different parts of the target.

In the game, if you look at the spread dial of the TDC, the game considers that the entire dispersion of the spread between the outermost torpedoes. In reality, that dial indicated the angle between each individual torpedo. So for instance if the spread dial read 3°, there would be 3° in between each individual torpedo, meaning that a spread of four would cover 9°. And given the German protocol of firing a spread only when the data is uncertain or the range is long, to hit one torpedo, that makes sense.

So now to translate that into game terms, if you want to mimic the German spread doctrine, don’t fire them if you plan on all eels hitting. In that instance, simply just shift fire on each subsequent shot. Only use spreads if you are very uncertain of your data or are at long range as somewhat of a Hail Mary.

And, spread them wide. To mimic how the real TDC worked and how the real gyro angle receiver set the gyro spindles, you can use your periscope to measure the angular length of what you are shooting at, and then multiply that by:
- 3 for a spread of 4
- 2 for a spread of 3
- 1 for a spread of 2
Set the result on the spread dial.

So like the example from before, if you can see that the target is about 3° wide so to speak in your periscope, and you want to shoot a spread of three, set 6° on the spread dial. It will send one torpedo where you aimed, one torpedo 3° left and one 3° right, greatly increasing the chance of one hit even on bad data.

As an aside, the German fire control system incorporated a spread angle calculator that took range, target length, and AOB into account to compute the spread angle that was transmitted to the gyro angle receiver. Prior to the model S3 this was a separate unit in the tower, and it was incorporated into the computer with the S3. The operator of the gyro angle receiver in the bow room matched the spread angle by hand (matched the pointers) and that set the gyros in the eels to the correct ratios. The spread was fired automatically by holding the firing lever down until the last eel left, at an interval of 2.5 seconds between eels, different than the US which fired each individually.