Hardcore TDC

[Gorshkov]

Supposedly TDC on-board American subs works now as it did in reality. So I am looking for some tutorial describing TDC work at the highest level of realism. I am especially interested in feature enabling check if my firing solution entered previously into TDC is still valid.

[Hitman]

Actually the current in game version is a just pale resemblance of the amazing piece of machinery that the real one was :DL

There are many differences, but to list the more important ones:

- In game you have way less flexibility in the input of data
- In game many parts & dials are not displayed or functional
- In game there is no fast forward feature to check the predicted position of submarine and target in the future

I don't remember right now that anyone made an indepth tutorial of the TDC in a document, but IIRC there are some videos about advanced use of it in the Sub skipper bag of tricks thread, stickied somewhere in the main SH4 forum. In any case, be sure to get the fantastic 3D TDC and radar mod by Nisgeis; there is a thread about it in this forum.

Good hunting :up:

[Gorshkov]

Well, I did not find good TDC description in the suggested thread but this new "3D TDC & Radar Ranging" mod looks awesome! What a hell machine have you created? Does this stuff really work as real targeting system?

[Jan Kyster]

Not sure if this one is any good? Manual TDC... http://www.subsim.com/radioroom/showthread.php?t=116987

Warning! Swearing and bad language occurs... :D

[Gorshkov]

I am afraid thread linked above is a bit outdated because later patches modified TDC/periscope aiming a lot. Now in stock SH5 version 1.5 this works as follows:

1. Lock target with periscope.
2. Identify target and send this information into TDC.
3. Measure range to target using stadimeter and send this data along with actual target's bearing into TDC.
4. Wait awhile and then repeat step 3.
5. Obtain target's speed (it is measured automatically after patch 1.3 or 1.4) and enter it into TDC. In this moment Navigator will give you precise target's course estimation.
6. Use this information to adjust AOB and send it into TDC, too.
7. Enable Position Keeper.

Now your firing solution is complete!

Of course you can also obtain course and speed yourselves by plotting tactical situation on Navigation Map, using three minutes rule, nomograph, sonar or radar data. Yet method presented above is now a basic periscope/TDC targeting technique in SH4.

[Nisgeis]

Be careful using the estimate speed button, as if you click it a few times, you will get different answers, a degree either side of the course which isn't so bad, but you'll get a speed a knot either side. Why the estimate should change based on the same two observations is beyond me.

Also be wary of sending last minute updates to the bearing, as it will reset the range to the last measurement and it will also screw up the target course, as it doesn't update the AoB. A real TDC would update both the range and the AoB on bearing change.

[Gorshkov]

OK, so the better solution is to remove resending bearing from my "targeting algorithm". As for speed measurement you should use another method. Everything depends on acutal tactical situation, amount of time available, distance to target etc.

It is sad in-game TDC is still buggy...

[Rockin Robbins]

I am afraid thread linked above is a bit outdated because later patches modified TDC/periscope aiming a lot. Now in stock SH5 version 1.5 this works as follows:

1. Lock target with periscope.
2. Identify target and send this information into TDC.
3. Measure range to target using stadimeter and send this data along with actual target's bearing into TDC.
4. Wait awhile and then repeat step 3.
5. Obtain target's speed (it is measured automatically after patch 1.3 or 1.4) and enter it into TDC. In this moment Navigator will give you precise target's course estimation.
6. Use this information to adjust AOB and send it into TDC, too.
7. Enable Position Keeper.

Now your firing solution is complete!

Your firing solution is complete and you will miss astern.:shifty:

You executed your steps in the wrong order.

[Gorshkov]

Having fired many times during tests and always hit so far. :)

[Rockin Robbins]

There are two problems with your setup. It's all explained in the Sub Skipper's Bag of Tricks thread in detail.

First of all, you need to turn on the PK before you get a range/bearing input. Second the target speed and AoB have to be in before you input the range/bearing. I always turn on the PK first if I'm going to use it. That way I don't forget it.

But for the PK to do you any good at all, it has to move its phantom target aiming point right along with the real target. For instance, if you do it your way and get range/bearing first, sure the TDC knows where the target was. But the aiming point just sits there while the real target steams off. You're already behind the 8-ball.

Then you figure out the speed and enter it. There's no effect. The TDC continues to project the target at the exact spot where you took that range/bearing reading. The speed is in the TDC, but the TDC isn't using it to move the aiming point, so your real target is STILL steaming away from your aim point at full speed.

Now you're going to figure out the AoB and enter it. Well, that took a bit of time and the aiming point is STILL stationary while the real target is even further from that aiming point.

So NOW you're finally going to hit the PK button? Fine, you've got an aiming point that is trailing the real target by 100 yards times the number of minutes you took to do all that in the wrong order. If you did it all in one minute, you're off by 100 yards, enough to barely hit a large target on the stern, if he's close in. If you're shooting at a target 2000 yards away, just forget it.

1. Turn on PK
2. Calculate speed and enter it. Why? It takes the longest.
3. Enter the AoB. Why? You found the target course when you calculated the speed. It's available with no delay.
4. Take range/bearing. Your aiming point is already traveling at the same course and speed as your target. All you need to do to put it dead center is that range/bearing position. INSTANTLY when that point is plotted it begins moving at the speed and on the course you've told it to go. It stays exactly on the target.

Now you have an aiming point exactly centered on your target and if you entered all info correctly, you'll hit whenever you want to fire. If you think about the way I've explained it you'll have to agree that it is correct.:up:

[Gorshkov]

Your method is not comparable with mine: in your method virtual skipper has to perform speed and course calculations using navigation map, not periscope/dial input. Maybe it is more precise but I think on typical firing ranges both methods are acceptable. In fact I was able to hit target being 2000 yds away and positioned 50 degrees off-boresight.