Historically-Accurate TDC Usage

[Nisgeis]

Originally Posted by Bilge_Rat

could you explain that Nisgeis, I am not sure what you are referring to.

OK, you know how the German TDC is linked to the periscope, so that once you have the target course layed in, if you move the 'scope then the AoB gets updated, so the solution is correct?

Well, the US TDC has a similar feature. Let's say you are tracking a target at a speed of 6 knots, on a course at 90 degrees to your own course. If you suddenly notice that the target is gong much faster than you thought and you update the bearing, then in the real TDC, the range and AoB and everything do do with it would be updated at the same time, as the PK moves the ship along its course with a bearing change. Note that the TDC is not directly linked to the periscope, because that would mess up the PK, which is the fundamental reason why it is not directly connected, but the functionality of the German TDC is there.

In the SH4 one, you have to guess or measure with the stadimeter the range again at the same time as you send the bearing (as you have to send both together D'OH!), as otherwise it will still use whatever range it had as it isn't connected, but worse than that, it will still use the AoB it already without updating it based on the bearing change, so if you advanced the bearing by 10 degrees, the AoB used would be the old one prior to your change and therefore the target's course would be changed by 10 degrees, which would make a mess of your solution.

So, what would be a simple bearing change, means you have to re-enter everything again, hardly the refinement of a solution the TDC was designed for. It also ramps up the amount of work you have to do if you discover an error at a late stage of the attack.