Historically-Accurate TDC Usage

[SH4 fan]

Originally Posted by Bilge_Rat

How does that work?

I basically follow the method set out in the manual, with my own refinements:

1. ID ship (enter in TDC);
2. get first range reading from stadimeter (enter in TDC);
3. start stopwatch;
4. plug in observed AOB (enter in TDC);
5. plug in trial speed (from sonar station, i.e. "slow", "medium") (enter in TDC);
6. start PK;
7. plot estimated TGT position on NAV map (based on range and bearing in #2 above) (i.e. Mark #1);
8. after 3 minutes as shown on stopwatch, determine new range with stadimeter (re-enter in TDC);
9. plot new estimated TGT position on NAV map (based on range and bearing in #8 above)(i.e Mark #2);
10. draw line from Mark #1 to Mark #2. From this you can reasonably estimate TGT's course and speed;
11. plug in new observed AOB, as determined from course in #10 (re-enter in TDC);
12. plug in calculated speed from #10 (re-enter in TDC);
13. fire torpedoes, based on best range as shown on the Attack Map.

It is a bit cumbersome, but highly accurate. Obviously, I may have to refine the solution between 12 and 13, based on observation of the TGT and how it matches up with the TDC solution.

I don't even need to ID the target. I don't always use, 11,000y and often times will use less if time permits but it is an easy input since it is the max range on the stadimeter.

1) track radar target
2) calc time, speed, distance, and course.
3) plot 90° to target course.
4) measure distance to target course
5) Plot 11,000y (5.4nm) from me on enemy course line
6) measure AOB from that point
7) input speed, AOB, distance in TDC
8) watch target pass 11,000y mark
9) activate PK
10) adjust speed and range as necessary
11) let the fish swim.

All triangles add up to 180 so even if it is not a 90° intercepts all you need to do is, AOB = 180 - (course intercept angle + RB to target)

It is a very accurate method, I only use the periscope to refine the final solutions and ID the target.