Obtaining firing data

In order to accurately and reliably hit your target with torpedoes you will need to obtain firing data for them. For the torpedo data computer in the Type VII this means you need to obtain Angle on bow, speed, range and bearing. There are several methods of obtaining these values, all with their own strengths and weaknesses. Depending on how own ship and target is placed relative to each other some values are more important to get accurate than others. For instance when shooting at long range, range is less important than when shooting at short range. Also, when own ship is pointed at the target range is almost irrelevant, but when the target is to the side of own ship, range can be very important. Shooting from in front or behind the target, speed is less important, but AOB is more important, compared to shooting from abeam the target, where speed is very important, but AOB is slightly less important.

The predominant method used by U-boats during WWII is matching. It requires no math and no knowledge of the target in order to obtain good data, but it does take some time to ensure accurate results. Plotting is an other reliable but somewhat slow method, which can easily be used in conjunction with matching. This method does however require accurate ranging, which may require target data to be known. Last slow method is the 4-bearing method. This was not invented before after WWII, and as such is not historical for the Type VII. It's advantage is that it only needs accurate bearings and timing, however it is difficult to achieve accurate results with the tools available in the game.

There are a few quicker methods available as well. The Fixed wire method is possibly the the fastest way of obtaining target speed with reasonable accuracy, however it does require you to know the length of the target accurately, and you need to have a clear line of sight to the bow and stern of the target. When shooting at close range it is not critical to know the speed very accurately, and thus it might be sufficient to make an educated guess, which may or may not be faster. For AOB one has to rely on Visual AOB methods for quick measurements. These can be very accurate for AOB 0, 90 and 180, but in between accuracy is mostly only appropriate for short range shooting.