German TDC

[Bubblehead1980]

Started a real career finally...


Started in September 1939...

Sunk a Queen Elizabeth Battleship in two attacks over20+ hours...she was escorting a convoy with three destroyers.


On Second patrol now, have two merchants down by torpedoes, with three torpedoes left. I've had misses but also premature explosions and suspected deep runners.


I've had some misses though, which upon analysis are attributed to issue with proper final firing bearing. I've got the speed (metric system took time to adjust to for plotting) but the weakness is the final firing bearing with german TDC.

In the US TDC, you place the crosshairs on desired impact point, send final bearing to TDC and fire torpedo, send updated bearing, fire again and so forth or place on middle or target, send bearing. Wait for five seconds, fire, wait, fire. The TDC updates the bearing constantly, the advantage of the position keeper on US TDC.


With German TDC. What is the best way to fire on final bearing for accuracy? To lock in that final bearing.

[derstosstrupp]

Originally Posted by Bubblehead1980

Started a real career finally...


Started in September 1939...

Sunk a Queen Elizabeth Battleship in two attacks over20+ hours...she was escorting a convoy with three destroyers.


On Second patrol now, have two merchants down by torpedoes, with three torpedoes left. I've had misses but also premature explosions and suspected deep runners.


I've had some misses though, which upon analysis are attributed to issue with proper final firing bearing. I've got the speed (metric system took time to adjust to for plotting) but the weakness is the final firing bearing with german TDC.

In the US TDC, you place the crosshairs on desired impact point, send final bearing to TDC and fire torpedo, send updated bearing, fire again and so forth or place on middle or target, send bearing. Wait for five seconds, fire, wait, fire. The TDC updates the bearing constantly, the advantage of the position keeper on US TDC.


With German TDC. What is the best way to fire on final bearing for accuracy? To lock in that final bearing.

Center mass of the target. The biggest advantage of the German device over the American one was the direct transmission of the bearing from the optics to the computer. Remember the German device is not position-keeping - once you ascertain the AOB, you switch “on” the TDC to update, and from then on as you follow the target, the AOB updates as the bearing changes. This is a result though of you turning the optics. This made it so you didn’t have to shoot “im Durchwandern” (meaning placing the optics on the “shoot bearing” and waiting for the target to cross). You could follow the target with the optics, the computer’s bearing is tracking with the optics, and best case you fire when the gyro is low.

So in practice in game (different than in real life since SH TDC lacks functionality):
1. Gather your data using whatever method you prefer and note it down.
2. Once on your final attack course, set up the TDC with AOB and speed and the range you will likely fire at.
3. Switch TDC to start tracking.
4. Follow the target and watch the AOB develop, adjust as necessary.
5. Watch your gyro angle on the TDC and fire when the gyro is within 20 deg of your bow, aiming at desired impact point. Low gyro is not necessary but eliminates range as a decisive factor.

In real life (not relevant to game but if curious):
At any point, even before diving to approach, place optics on target, set AOB into the computer, switch follow switch on TDC to accept bearings from optics, and turn on the AOB motor. From now on, as long as the target maintains course, AOB need not be touched again - the computer will take all own course and target bearing changes into account to maintain the correct AOB. This was the major advantage of the S3 over the previous models.

[Bubblehead1980]

Originally Posted by derstosstrupp

Center mass of the target. The biggest advantage of the German device over the American one was the direct transmission of the bearing from the optics to the computer. Remember the German device is not position-keeping - once you ascertain the AOB, you switch “on” the TDC to update, and from then on as you follow the target, the AOB updates as the bearing changes. This is a result though of you turning the optics. This made it so you didn’t have to shoot “im Durchwandern” (meaning placing the optics on the “shoot bearing” and waiting for the target to cross). You could follow the target with the optics, the computer’s bearing is tracking with the optics, and best case you fire when the gyro is low.

So in practice in game (different than in real life since SH TDC lacks functionality):
1. Gather your data using whatever method you prefer and note it down.
2. Once on your final attack course, set up the TDC with AOB and speed and the range you will likely fire at.
3. Switch TDC to start tracking.
4. Follow the target and watch the AOB develop, adjust as necessary.
5. Watch your gyro angle on the TDC and fire when the gyro is within 20 deg of your bow, aiming at desired impact point. Low gyro is not necessary but eliminates range as a decisive factor.

In real life (not relevant to game but if curious):
At any point, even before diving to approach, place optics on target, set AOB into the computer, switch follow switch on TDC to accept bearings from optics, and turn on the AOB motor. From now on, as long as the target maintains course, AOB need not be touched again - the computer will take all own course and target bearing changes into account to maintain the correct AOB. This was the major advantage of the S3 over the previous models.

Thanks for your response, I believe I understand lol. Thinking next patrol will have improved shooting.

The buttons on TDC I circled in the shots below...When "on" I noticed the periscope is "slaved" to the periscope cant input data, but when off, and can input data. After inputting data, you hit the button to be "on"?

Problem is when I do that it seems to foul the solution up.

This I believe is the source of my misses, esp on longer range shots or a maneuvering target who's bearing and angle is changing. On US side of things, I am quite skilled at hitting zigging targets, but having trouble with German side thus far. I sunk two ships by torpedo last patrol, a third by gunfire after my last bow torpedo missed astern, I believe due to bearing issue, I had the speed correct.


Also, with G7e electric torpedoes...best to fire with a lead correct? due to its slower 30 knot speed. With MK 18 electric torpedo on US side always aim just ahead of desired impact point so it will hit there.

[Pisces]

The German TDC does take care of the lead for different speed torpedoes. No need to add a manual analog measure of lead by eye-estimation. But SH3 does have a bug of not updating the lead calculation when you switch to a tube with different speed setting. Like you have tube 1 with Type 1 Steam with fast setting 44 kts (3 settings: 30, 40, 44 kts). And tube 2 with Type 2 Electric (fixed) 30 kts. Tube 2 is selected and for whatever reason you decide to switch to tube 1. It will fire the type 1 torpedo with lead for 30 kts. As a work around you need to select a different speed for tube 1 (type 1 torpedo) and back to fast speed to reset the lead calculation by the TDC. Or make it a custom to always use the slow speeds and always make sure the type 1 torpedoes are set to slow.

[Pisces]

Originally Posted by Bubblehead1980

... I noticed the periscope is "enslaved" to the periscope cant input data,...

Typo there? Periscope slaved to periscope. I'll leave it to Stosstrup to answer. He is better at this, and I am not familiar with this particular GUI mod.

[derstosstrupp]

The easiest way to do it in SH games is to calculate the AOB that corresponds to a particular bearing, place your optics there, set the AOB into the computer and then press that TDC button you have circled. Then at that point as long as the target does not maneuver, you don’t need to update AOB again. Remember though that you can’t change course either because the TDC will not take that into account in the game.

For example:
I parallel the target at maximum range and I determine its course as 000. I overhaul it until I am a decent distance ahead and I dive. I approach on course 270. Once the range is about 1000 to 1500 m I start setting up the computer for the attack. I push the “button” to allow me to input data. Since I am on a perpendicular course, I place my scope on bearing zero, set the AOB right 90, and then press the TDC’s “button” again. Now when I slew back onto the target, the AOB will be correct in the computer.

If you are not on perpendicular course, you can use the attack disc or whatever course finder you prefer, or simply math to figure out the AOB based on the bearing.

Formula is:
AOB = Own course + relative bearing - 180 - Target course
If answer is less than -180, add 360
If answer is greater than 180, subtract 360
If answer is negative, target’s bow is left

[Bubblehead1980]

Originally Posted by derstosstrupp

The easiest way to do it in SH games is to calculate the AOB that corresponds to a particular bearing, place your optics there, set the AOB into the computer and then press that TDC button you have circled. Then at that point as long as the target does not maneuver, you don’t need to update AOB again. Remember though that you can’t change course either because the TDC will not take that into account in the game.

For example:
I parallel the target at maximum range and I determine its course as 000. I overhaul it until I am a decent distance ahead and I dive. I approach on course 270. Once the range is about 1000 to 1500 m I start setting up the computer for the attack. I push the “button” to allow me to input data. Since I am on a perpendicular course, I place my scope on bearing zero, set the AOB right 90, and then press the TDC’s “button” again. Now when I slew back onto the target, the AOB will be correct in the computer.

If you are not on perpendicular course, you can use the attack disc or whatever course finder you prefer, or simply math to figure out the AOB based on the bearing.

Formula is:
AOB = Own course + relative bearing - 180 - Target course
If answer is less than -180, add 360
If answer is greater than 180, subtract 360
If answer is negative, target’s bow is left

My problem is not the data its operating the German TDC properly but believe may just have it figured out.

Thanks for the help

[derstosstrupp]

My last post describes how to properly operate it but glad you’re sorted.

[Bubblehead1980]

Originally Posted by Pisces

Typo there? Periscope slaved to periscope. I'll leave it to Stosstrup to answer. He is better at this, and I am not familiar with this particular GUI mod.

Yes, typo.