Yes I have read it and I have a lent a copy of the book from the library and so far this is the best source I currently have, and I thank you for that. It has got me a long way but when writing a simulation (of whatever it is) you really have to understand every detail of the thing you want to simulate. And while the basic stuff with distance, bearing, AOB and speed is simple enough, new questions arise when you actually want to penetrate the TDC's function.

For instance how does the programming of a spread work? Do you enter an angle, or a distance at the target, for instance 50m and the angle is calculated? Will it spread left or right and how do you select that? Was the TDC able to "track the target" I mean did it update the targets position according to the data you once feed it, as the American TDC's where able to do? Or was it just an instant Angle solver? As I understand it, it was able to track the target, but since my German is quite shaky I'm not 100% sure I have read it right. Also I have a weak memory that says that it wasn't able to track a target so I'm not really sure what to think.

Anyway, I have many more questions but it seems that the TDC isn't that well known even amongst us u-boat fans. So I won't bother the group with these, at least not right now

Leif...