Hosed by the TDC!

[Antiacus]

So i'm patrolling up in AN23 near the British sub base. I've got 2 torpedoes left and detect a cargo ship at 23km heading straght for me.

"Perfectioso" I say to myself. (i'm part spanish and playing an exile of the Spanish civil war).

So I plot out his course (about 175) and set up for a 90 degree shot at 1km.

Chuckling to myself at my good fortune i set the TDC to 90 degree AOB and 1km range. I also took the opportunity to set both torps at impact and fast speed.

When he gets up to about 3km i point my bow at him and establish 10kt speed. I'm all set! Easy pickins!

reset my bow to 90 degrees to his course, double check his course, make a tiny adjustment to get back to 1km range and i'm all set.

When he gets to 0 degrees on my scope i unlock, set one loose just a little forward, and one just a tad aft.

I smugly wait for the impact and the adolation of my adoring crew.

Nothing...

Hmmm. I set those to fast right? Yeah, pretty sure.

Nothing.

WTF

Nothing.

I check the TDC map and it shows my aim as being well aft of his position at 90 degrees. Mhuaah?

I check the TDC and the far left guage is set at about 30 degrees left of 0. I'm assuming that's relative bearing from my vessel to his. Not sure why this was at 300 but i blame the weps officer.

I tell the crew that we had a faulty torpedo and set sail for Kiel.

I'm assuming that the automatic updating the TDC does after being closed caused this to happen. I'm displeased and take it out on the crew. Port and Starboard duty, no holiday underway, I want no rust showing by the time we reach Kiel.

-Antiacus

[Pisces]

Ofcourse, the tools are allways the cause of screw-ups. I don't understand why we use them anyway. Let me adress some of the points where I think you fool... erhm, tools got jammed. ;)

When he gets up to about 3km i point my bow at him and establish 10kt speed. I'm all set! Easy pickins!

reset my bow to 90 degrees to his course, double check his course, make a tiny adjustment to get back to 1km range and i'm all set.Not really the cause of the miss probably, but why bother. The target is allready comming near right in front of you, right? No need to go closer. Just make sure you are close (1 km or so) to his track. Take a chill and wait. Let go of those nerves. 10 kts makes noise and makes you visible. A merchant may not notice, but a near DD might.

When he gets to 0 degrees on my scope i unlock, set one loose just a little forward, and one just a tad aft.This is probably the point where it goes wrong. You let the target in the scope pass 0 degrees before you fire. This means the TDC needs to aim the torpedo further ahead of the target (which is now right in front of you), and that makes the aim less accurate. Best would have been to fire when the gyro angle indicator is 0 degrees. This means the scope is looking some 5-15 degrees before crossing the bow (or stern for an rear-shot, and depends on target and torpedo speed mostly). This way the torpedo's do not need to turn after being fired.

Second, you aim ahead and aft of the target. Why not ON the target? A 3rd or 4th of the lenght from the bow and stern if you want to spread. But on it for sure. If you entered the propper values in the dials, the TDC is going to aim correctly so the torpedo's will hit where intended. Really, the TDC works perfect, as long as you know "garbage input"="garbage output". Simply do not fire until you are sure of the target course and speed. Range is less important. By aiming infront and behind you purpously ruined your aim. Not intended ofcourse, but you made the chances of a miss higher than a hit.

Then there is the fact that the torpedo doors need to be opened before being fired. If you don't, they will open automatically but the gyro angle will not be correct when the torpedo leave the tube (about 4 second old).

There is also the possibility you set the AOB to the wrong side. (you didn't mention direction) Point the dial in the direction the target crosses your scope. (red if "from right to left", green if "from left to right")

I hope that helps figure out what went wrong. I also hope I wasn't to harsh. TDC workings are tricky to understand. Mistakes are very understandable

[Antiacus]

Thanks Pisces.

I should have clarified better exactly what i did. To get his speed, i waited until he was about 10 degrees off the bow and timed him. Then applied OLC's whiz wheel to get the speed.

As for aim, I also was unclear. I aimed a little forward & aft of his beam so that i was actually still aiming for his hull.

I think where I fouled up was when i moved the attack peri to time him i had the TDC window closed so it updated his position at 10 degrees to port. When i moved back to zero i left it open (or maybe vise versa?) so it did not updated. Thus when i fired, the TDC believed he was 10 degrees to port rather than at 0 degrees.

I didn't, however, know that bit about the gyro angle. That makes perfect sense and i'll definitely be using that trick.

I'm still figuring out what exactly makes the TDC update and what doesn't. For instance, say if i set up exactly how i did and rather than manually input the data for range and AOB i used OLC's GUI and figured it all out when he was still 2500m up track from me. If i immediately close the TDC would it update everything as he approached and his range & AOB both changed?

Thanks again!

*edit* I should probably state what mods i'm using: GWX2.0, OLC GUI, and Torpedo Damage Final.

[snwcrsh]

With OLC it's as following:

Whenever TDC panel is open, *nothing* will update. Settings will be frozen and can only changed manually.

Whenever TDC panel is closed, the settings Bearing and AOB will get updated each time you move the periscope.

Range and speed can only be set manually or by the weapons officer (solution to target)

[Antiacus]

So TDC will update only bearing & AOB as the peri moves (as long as tdc windows is closed) and nothing else.

Thanks.

This game is pretty complicated for the trigonomically uninclined, but it's so rewarding when i finally get it right.

[snwcrsh]

Yes, exactly. And don't worry - it's complicated for everyone in the beginning, especially if you start with manual targeting from the start. I think it's less about trigonometry skills as lack of knowledge how to operate devices like torpedo data computers and whiz wheels designed for submarines. It's not exactly what we are taught in school (charming idea though) :)

[Pisces]

Thanks Pisces.

I should have clarified better exactly what i did. To get his speed, i waited until he was about 10 degrees off the bow and timed him. Then applied OLC's whiz wheel to get the speed.

As for aim, I also was unclear. I aimed a little forward & aft of his beam so that i was actually still aiming for his hull.

I think where I fouled up was when i moved the attack peri to time him i had the TDC window closed so it updated his position at 10 degrees to port. When i moved back to zero i left it open (or maybe vise versa?) so it did not updated. Thus when i fired, the TDC believed he was 10 degrees to port rather than at 0 degrees.

I didn't, however, know that bit about the gyro angle. That makes perfect sense and i'll definitely be using that trick.

I'm still figuring out what exactly makes the TDC update and what doesn't. For instance, say if i set up exactly how i did and rather than manually input the data for range and AOB i used OLC's GUI and figured it all out when he was still 2500m up track from me. If i immediately close the TDC would it update everything as he approached and his range & AOB both changed?

Thanks again!

*edit* I should probably state what mods i'm using: GWX2.0, OLC GUI, and Torpedo Damage Final.I see, for measuring speed you do need to turn your bow on him if you are moving rather fast. However 10 knots at an angle of 10 degrees makes the scope line to move sideways 1.7 knots ( 10*sin(10) ). That's not going to do your measuring any good. Slow down or a much smaller bow-on angle, prefferably both.

Allright, sounds like your aim itself was not the cause then. But more likely the TDC settings were wrong.

Yeah, leaving the TDC panel open is usually my most frequent mistake. I've lost many torpedos like that. And in a type 2 that matters bigtime to your patrol tonnage.

If you measure AOB well before the target crosses your bow and close the panel right away the TDC will update it when you turn the scope. For AOB measurement (with the OLCgui/Ujagd AOB finder) it is important to unlock scope immediately when you know the visible length so the scope doesn't turn further while using the AOB-finder. Or else the measured AOB and bearing (when the panel closed) do not match. Turning the scope does not update the range setting. That should be done just before firing, assuming it is a big factor in the gyro equation. I'm not completely sure, but I think range affects gyro-angle only significantly when the scope is far away from the bow/stern and range is rather close. The torpedo starts it's journey from the front/rear instead of under the scope, and I think also moves a certain distance straight out of the tube before it turns. At short ranges this turn is a bit bigger than if far away because of an effect known as 'parallax (http://en.wikipedia.org/wiki/Parallax)'. But how much that is I don't know. Best is to let the torpedo's not turn at all (no gyro angle) or within +-10 degrees.