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Old 03-22-14, 08:30 AM   #37
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Default Intercepting A Convoy Having Received BDU Radio Message By Stoianm

Last updated 31st December 2014

This Tutorial has been written to work with ‘Stoianm’s 3 part video’s ‘How to Intercept a Convoy Received By Radio from BDU in SH5.’

This Tutorial is played ‘With’Real Navigation’. This means the U-Boat’s current position will not be known until the Navigator plots a new one.

If you are playing ‘With’No Map Contacts’ then you may also find this ‘Tutorial’ useful.

My Documented part of this ‘Tutorial’ will assist you in your own ‘Game Play’ to tell you when to make the right movements and calculations.

Video Part 1 of 3 (10 minutes)

BDU Information Received

A BDU Radio message was received at 14.28 hours (11 minutes ago)

Convoy Speed > 10 Knots

Convoy Course > 306 degrees.

U-Boat Information from the Navigator

U-Boat’s Compass Heading > 276 degrees

Range to Convoy > 86 Km

Bearing > -114 degrees (Port Side)

True Bearing > 161 degrees.

Periscope Bearing > 246 degrees.

It is important that we start plotting as soon as possible. This can be done with the ‘Game Paused.’

1. Take the ‘Ruler’ and draw the U-Boat’s ‘Heading’ of 276 degrees.

2. Take the ‘Protractor’ and draw the ‘Bearings’ 114 degrees out to the left side.

3. Take the ‘Compass’ and place it on the U-Boat and draw out the ‘Range 86 Km’ alongside the ‘Bearing Line.’

4. Take the ‘Marker’ and mark an ‘X’ on the ‘Bearing Line’ where the ‘Compass Circle’ crosses it.

5. To know where to intercept the ‘Target’ we use what is known as the ‘Multiplication Factor Formula.’

6. This is the distance from the ‘U-Boat’ and the ‘Targets distance 86 Km.’ It is divided by 86/100 = 0.86 x 3.33 = 2.86 MF (Multiplication Factor.)

7. Take the ‘Ruler’ and from the ‘X’ mark on the ‘Bearing Line’ draw out the ‘Targets Course’ of 306 degrees.

8. We know the ‘Convoys speed is 10 Knots.’

9. The calculation is going to be 2.86 MF x 10 Knots = 28.6 Km.

10. Take the ‘Marker’ and mark an ‘X’ 28.6 Km along the ‘Convoy Course Line.’

Video Part 2 of 3 (10 minutes)

11. We now need to get the U-Boat’s calculaton.

12. MF 2.86 x Our Speed 15 Knots at ‘Ahead Flank Speed’ = 42.9 Km.

13. From the 28.6 Km mark on the ‘Convoy Course Line’ take the ‘Compass’ and draw out 42.9 Km.

14. ‘Erase’ previous ‘Compass Circle.’

15. Where the ‘Compass Circle’ crosses the ‘U-Boat Bearing Line’ take the ‘Marker’ and place an ‘X.’

16. Now we need to take the ‘Protractor’ to make an angle from the ‘X’ mark on the ‘Convoy’s Course Line’ to the ‘X’ mark we have just made on the ‘Bearing Line.’

17. This shows us that the angle is ’23 degrees.’

18. We need to use this angle of 23 degrees so that we can get an intercept point on the ‘Convoy’s Course Line.’

19. Take the ‘Protractor’ and draw out 23 degrees from the U-Boat so it goes through the ‘Convoy’s Course Line.’

20. Take the ‘Marker’ and mark an ‘X’ where the lines intercept.

21. Take the ‘Eraser’ and remove all except ‘Convoy’s Course Line’ and the two ‘X’ marks.

22. The next thing we need to know is how long will it take to reach the ‘Target.’

23. Taking the ‘Compass’ and measuring the distance between the two ‘X’ marks shows that it is ‘39.3 Km.’

24. Looking at the ‘Speed Charts’ shows that the time to travel this distance is around 2 hours and 10 minutes.

25. Looking at the U-Boat clock is showing 14.28 hours.

26. 14.28 + 2.10 = 16.38 rounded to 16.40 hours.

27. To find our heading we take the ‘Ruler’ from the U-Boat down to the intercept ‘X’ mark.

28. (Alternative Option) You could of course at this point head straight down to the ‘Convoy’s Course Line’ from where you are and set up a 90 degree firing position and just wait the extra time for the ‘Convoy’ to reach you.

29. (Resuming Our Plan Of Action) This shows we need to change course to ‘185 degrees.’

30. Order ‘Ahead Flank.’

Video Part 3 of 3 (10 minutes)

31. Change the ‘Message Box’ icon to ‘1TC.’

32. This is the 1st icon on the right next to the digital clock.

33. You can now use some ‘Time Compression’ but need to keep an eye on the clock.

34. At 16.00 Hours the ‘Navigator’ will automatically give a new positional fix.

35. At 16.20 hours we will order the ‘Navigator’ to fix our position.

36. We will ‘Stop’ at 16.30 hours.

37. The ‘Message Box’ is showing ‘Task Force Sighted.’

38. Go to the ’Watch Officer Icon 1’ (from right to left).

39. Go to ‘Icon 6’ ‘Nearest Visual Contact.’

40. He has now given us a bearing of ‘266 degrees’ and a range of ‘2600 meters.’

41. Order the ‘Navigator’ to give a new position fix.

42. Is it time to ‘Submerge.’

43. Your decision ‘Captain.’

44. Good Hunting.

If the speed is not shown in the ‘Message Box’ but shows ‘Slow – Medium or Fast’ always take the fastest relative speed. It is better to be early rather than late.

Courtesy acknowledgement to Stoianm

If you shade this Tutorial and then copy and paste it to your PC Notepad you can then edit it.

Last edited by THEBERBSTER; 01-17-18 at 05:44 PM.
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