Slide Rule Targeting for SHIII/SHIV

[Capt. S. A. Wood]

New here I guess. I have been reading the forums for a good month or more about DW and SHIV, but never had much to post about, was learning mostly. Have played 688(I) and the two aforementioned games so far.

I am baking here in this dorm room at 5:45 a.m. due to the lack of AC, so I can not really go to sleep. I produced a detailed step-by-step checklist of what Puster Bill put forth in the OP, because even though I suck at mathematics in the purest definition of sucking, I am intrigued by these slide rules. So before I go try out the methods in the game I figured I would just write a little checklist. Hope it is up to par and acceptable.

-----

Silent Hunter 4 - Wolves of the Pacific Slide Rule Targetting Checklist Using Model Pickett N909-ES

http://www.antiquark.com/sliderule/s...l-n909-es.html

Checklist is for two-reading intervals. Intervals can be chained together for more accuracy.
Examples given by OP are in [square brackets], important things are underlined, variables are in bold, and scales are in italics.
Scales used are S, C, and D.

-----

1.a. Obtain range to target and divide by 1000 with precision of 3 as Initial_Range --- [7.000]
1.b. Obtain bearing of target from own ship bow as Initial_Bearing --- [65]
1.c. Start chronograph and wait for 195+ seconds --- [0]

2.a. Stop chronograph and obtain elapsed time divided by 100 with precision of 2 as Time --- [2.40]
2.b. Obtain range and divide by 1000 with precision of 3 again as Final_Range --- [4.000]
2.c. Obtain bearing from own ship bow again as Final_Bearing --- [45]

3. Pause if desired --- [Nap Time]

4.a. Obtain bearing difference of Initial_Bearing and Final_Bearing as Delta_Bearing --- [20 = 65 - 45]
4.b. Align S (Delta_Bearing) with D (Final_Range) --- [S_20 | D_4.000]

5.a. Obtain new S value aligned with D (Initial_Range) and minus Delta_Bearing as Temp_Bearing --- [17 = (S_37 | D_7000) - S_20]
5.b. Obtain bearing difference of Delta_Bearing and Temp_Bearing as Offset_Bearing --- [3 = 20 - 17]
5.c. Adjust S by Offset_Bearing --- [3]

6.a. Obtain new S value aligned with D (Final_Range) as Final_AOB --- [23 = S_23 | D_4.000]
6.b. Obtain new S value aligned with D (Initial_Range) as Initial_AOB --- [43 = S_43 | D_7.000]

7. Obtain new D value aligned with S (Delta_Bearing) as Delta_Range --- [3.500 = D_3.500 | S_20]

8.a. Align C (Time) with D (Delta_Range) --- [C_2.40 | D_3.500]
8.b. Obtain new D value aligned with C (1) as Speed --- [14.6 = D_14.6 | C_1]

9.m. METRIC: Align C (5.144) with D (Speed) --- [C_5.144 | D_14.6]
9.i. IMPERIAL: Align C (5.626) with D (Speed) --- [C_5.626 | D_14.6]

10. Obtain new D value aligned with C (1) as Knots --- [28.2 or 26 = D_28.2 or D_26 | C_1]

-----

Input relevant values into TDC and have a nice day

-----

+ Full credit goes to Puster Bill of course

- Wood

Edit: Changed variable name WTF_IsThis to Delta_Range thanks to clarification from don1reed
Edit: Various changes made to match OP's changes, which should match up now