[TorpX]

Ok, I'll try to give you a quick lesson on the TDC.

First, know that the AoB is just one part of the firing solution. To compute a proper firing solution, you need four things:

1. Aob - often estimated by 'eye'. Many in this game, use plotting with the map-contacts, to determine this on the nav-map.

2. Range - usually estimated by use of the stadimeter, or RADAR.

3. Speed - usually estimated by using the plot; distance moved divided by time. Rule of thumb: distance in yards moved in three minutes / 100 gives speed in knots (approximately). So, a target that moves 800 yards in 3 min. can be said to have a speed of 8 knots.

4. Bearing - this is self-evident from index ring on periscope or TBT.

If you are new to the game, or rusty, I would advise to use the map-contacts option. This will give you certain and precise locations to plot on your charts, and you can get a feel for the way the AOB compares to the view of the target you see. You should periodically pause the game, and study the dials and outputs of the TDC, so you can develop an understanding of the geometry involved.

Note that many different methods have been used to compute firing solutions, according to the inclinations of the players. If you don't use the map-contacts option, it is much harder to estimate AoB, and range, (and thus speed computations are likely to be off), so the whole business becomes very uncertain.



In the diagram below, the target ship is at T0, moving toward T1, and the sub is at U0 moving toward U1. The Aob is the angle measured from the target's bow to the bearing line of your sub. It can be port (left) or starboard (right). [Maybe you already knew this?]

As I said before, you can determine the Aob by measuring it off the plot, after you have marked several observations. This is probably the easiest way, if you are using map-contacts. In real-life, skippers usually estimated it by 'eye-balling', or with calculations involving the aspect ratio.

I won't say this, or any way is 'best', that might lead to arguments here, as everybody has their own favorite.

Note that the Aob is likely to change throughout the approach, even though the target is following the same course. This will sometimes lead to confusion.