OLC GUI - Attack Disc Instructions

[CanuckBoat]

After playing through OLC GUI, I think I finally got the hang of the attack disc and its uses. I wanted to share what I've learnt about this useful tool and I also wanted to see if anyone else can tell me more about how to use this tool.

A picture of the attack disc can be found from OLC's post:
http://farm3.static.flickr.com/2031/2275450025_eec44210c3_o.jpg

Components of the Attack Disc:
a) Four circular scales. For the purpose of this post, I will label them Scale A, Scale B, Scale C and Scale D from outside to inside.

b) Scale A rotates with the UBoat so that at any given time, the true course of the U-Boat is indicated by the white triangle at innermost part of Scale A against Scale B.
In the picture, the current true course of the U-Boat is 334 degrees. You can also use the white triangle to visualize. If you think of North as "up", then the white arrow indicates the U-Boat course relative to that.

c) Scales B, C are fixed and do not rotate. Scale B is for reading reading true courses. Err. I haven't figured out what Scale C is for (yet)

d) Two user turnable rings. The outer ring is used for entering relative angle to target. To do this, you rotate the outer ring so that the relative angle to target lines up against Scale A.

e) The inner ring is attached to Scale D. This inner ring is used for entering the target's AOB. To do this, rotate the inner ring so that the AOB on Scale D (green for starboard, red for port) lines up against the outer ring's back arrow.

Attack Disc Purpose:
a) To determine the true bearing to target based on one variable: i) relative angle to target (this is the attack scope/uzo/observation bearing reading, or the watch officer's reported bearing, or the hydrophone officer's reported bearing).

b) To determine a target's true course using two variables: i) relative angle to target ii) observed AOB based on using the AOB finder in the OLC GUI. (PRIMARY USE)

c) Once the target's true course is known and a course line established, the U-Boat can then manuever to a better firing position. Once the target's true course is known, the U-Boat can freely turn and maneuver. If the target does not change its course, the attack disc can be used to determine the proper AOB settings to enter into the TDC for an accurate firing solution EVEN if the UBoat has turned after calculating the original AOB.

Using the Attack Disc:

i) For purpose a) above, all you have to do is to rotate the outer ring so that the back of the outer ring lines up with the relative angle to target on Scale A. Then you can read the true bearing to target on the front part of the outer ring lined up on Scale B. For the picture example, the relative angle to target is 165 and the true bearing to target is 139. Please note that you can use this relationship even if the target's true course is unknown. In fact, if you took a range reading from the OLC AOB finder, I would recommend that you use this method to quickly plot the target's position.

ii) for purpose b) above, rotate the outer ring so that the back of the outer ring lines up with the relative angle to target on Scale A. Next, To do this, rotate the inner ring so that the AOB on Scale D (green for starboard, red for port) lines up against the outer ring's back arrow. For the picture example, the U-Boat is travelling at a true course of 334 degrees. The relative bearing to target is 175 degrees. The true bearing to target is 139 degrees. The AOB is 49 degrees to the starboard. Therefore, the target's true course is 270 degrees (heading directy west).

iii) for purpose c) above, rotate the outer ring so that the back of the outer ring lines up with a new relative angle to target on Scale A. Then you can read the AOB needed to enter into the TDC by reading Scale D lined up against the back of the outer ring. This is VERY useful if you manuvered to a new position and need to enter AOB data into the calculations but do not wish/have no time to recalculate the AOB. Swich TDC to auto, rotate a scope to a new position to fire (Ideally this should be close to 0 for the forward tubes) Switch TDC to manual and enter in the AOB determined from the attack disc. Switch scope to auto. Now look for a position with close to gyro=0 and fire when target point passes.

I hope everyone found this at least a bit useful. I would add pictures in a word document if there is some interest.

CanuckBoat

[Platapus]

Great write up! :up:

I think dial "c" is just the recip. of dial "b". I also don't understand why or when you would ever reference dial "c".


I am still learning how to use the OLC GUI and I appreciate this explanation.

[klh]

CanuckBoat,

Welcome to the Subsim forums. It looks like you've done a good job at sussing out how to use the attack disc (Angriffsscheibe).

I don't use the one in the excellent OLC GUI because I built a home-made one from Hitman's templates (I like the added realism of using my hands instead of the mouse). It works similarly to the one in the OLC GUI, which is modeled after Joegrundman's U-jagd tools. I wrote a handbook (with Joegrundman's and Hitman's help) on how it can be used in the game. You can find it on my filefront page (see my signature), or look here...

http://www.subsim.com/radioroom/showthread.php?t=126824

By the way, Scale C, as you call it, represents a reciprocal bearing for the target. It is not actually a separate dial, but simply a second scale on Disc B. In the picture you attached, if your true bearing to the target is 320, then the target's true bearing to you is 140. It does come in handy.

One of my favorite ways to use the Disc is to determine a perpendicular attack course, then calculate the lead angle based on my torpedo speed and the target speed. Then I can fire a 0 degree gyro angle shot at any distance when the target crosses the lead angle. Hits almost every time, even from long range.

Keep asking questions. That's one of the ways we've learned what we have about these interesting tools.

[KeldorKatarn]

For that OLC GUI's attack disk is missing some dials though isn't it? It isn't as complete as the U-Jagd tools one, from what I can see, right?

I thought already about modding those in, but OLC's mod is pretty complicated if you haven't edited anything in menu.ini for a while :P

[klh]

For that OLC GUI's attack disk is missing some dials though isn't it? It isn't as complete as the U-Jagd tools one, from what I can see, right?

I thought already about modding those in, but OLC's mod is pretty complicated if you haven't edited anything in menu.ini for a while :P

You're right, the OLC GUI attack disc is missing the "Vorhaltwinkelscheibe mit Peilarm" dial. It is still usable without it, but you'll have to do the lead angle calculation in your head. You could try using Joegrundman's U-jagd tools to mod your OLC version. Or maybe OLC will issue an update? :hmm:

[CanuckBoat]

Thanks a lot klh. I searched the forum for "attack disc" and didn't come up with detailed instructions. I totally missed Hitman's wheel. Until OLC's GUI mod, I've almost exclusively used the Wazoo's Fast 90 method.

I downloaded your handbook and it is EXCELLENT. Thanks very much for writing it. I think I understand things much better now.

It was a bit of a struggle for me to learn how to use the disc because the video tutorial for this part was very quick for someone who has never used a disc before.
But, the effect was well worth it. Last night, I started a new career and stalked a large convoy of 1 Medium Cargo, 5 Granville Freighters plus a host of smaller ships. Upon inial target sighting, I collected range and AOB data. Then using the attack disc, I figured out the true coure of the convoy. It was 3:30 AM and I got out of visual range and then flanked the convoy. Once I managed to flank the convoy, I snuck into the middle of the convoy at a perpendicular course to the convoy to pick on the juciest target (1 Medium Cargo). Seeing that Medium Cargo go up in flames made my day :D

I find that using the disc (in conjuction with OLC's AOB finder) allows me to do "higher level" thinking because I can now consider things like convoy escorts and ways to sneak in and target priority much better since I don't have to struggle and fumble so much with plotting and marking.