Oh no, not another manual targeting procedure!!!

[ronbrewer]

Originally Posted by Maraz
When do you exactly switch to auto TDC? After entering target speed?

That's right. Once I adjust the speed dial on the TDC I click the button to turn the light red so that it will start updating the gyro angles based on periscope movement. I also open the tube doors right after this since all torp settings are done.

I didn't mention it in the original posting but I also configure the torpedo pistol setting, running speed, and depth during the target's 20 degree run while the hydrophone guy whispers the updated target bearings. Makes the atmosphere in the conning tower a little tense.

One thing I haven't found good info on, historically speaking, is when the weapon officer would open the tube doors. I've been going on the assumption that they should not open until all TDC input data is complete. I also found out the game doesn't let you shut them if you go below 20 meters when evading DD's so I keep them shut until right before firing. Though it's not modeled in the game open tube doors should reduce the sub's depth ability.

Also, thanks for the heads up on the Filefront website. The following link is has the spreadsheet for right triangle attacks:

http://files.filefront.com//;7409015;;/

And this link has the spreadsheet that computes lead angles based on AOB and torpedo impact times (for defective TDC simulation or WWI style solutions):

http://files.filefront.com//;7409021;;/

Both are in Excel format and on the second one just enter in different AOB numbers to get updated lead angles. You'll find the same angles for AOB 80/100, 70/110, etc. I just printed out each table and stapled them together in a booklet format. Basically what you do in the game is set the TDC button to a green light so the periscope swings freely and the gyro angles stay at zero. You then have to position your sub to provide the lead angles for the torp based on the target's AOB. For example, if you get on a perpendicular course to the target you know that it will be at AOB 90 when it crosses your bow. Let's say the target is going 9 knots and you have the torp speed set to 40 knots. The spreadsheet shows a lead angle of 13 degrees needed for these speeds so you would turn the sub 13 degrees to the left (or right for a starboard attack) and then turn the periscope back to a 13 degree setting (or 347 degrees if starboard) and fire the torpedo when target's center reaches a bearing of 13 degrees (AOB 90). The torp will run staight ahead due to zero gyro angle and range really won't come into play. However, if you do a range check you can use the second tab of the spreadsheet to get an estimate of the torpedo impact time.

After doing this on a few patrols I really learned to appreciate that TDC!!

Thanks,
Ron

[ronbrewer]

Originally Posted by Puster Bill

By the way, Hitman is working on a whiz wheel/circular slide rule based on one that was actually used for targeting in U-boats during WWII. He's already made some good progress:
http://www.subsim.com/radioroom/showthread.php?t=113591

Yes, I saw that thread on Monday and I'm really looking forward to his work. He did a great job on the American version. When there is bad weather or poor visibility I think the slide rule method using a collision course is still the best way to intercept since it's tough to do a range snapshot and you have to get really close to verify AOB.

[MudMarine]

I understand that the S-Class Boats in the campaign does not have a TDC. Is this correct?

If this is correct those tables will be very useful.