Hi Folks,
The following discussion will probably seem like overkill since I am sure you have a clear understanding, but I wanted you to be able to get inside my "head" (thoughts) and follow my thinking. Years ago I had a clear understanding, but today I am not so sure. I think I need your help to realign my thought processes and/or methodology. Anyway, I hope you can because I must definitely be doing something wrong.
Here we go!
For the discussion below...
SHT = Silent Hunter game time
NST = The time displayed on YellowSubmarine's Sextant at time of shot.
For starters...
--- I have no idea if I am supposed to factor in Magnetic Declination and even if I did should I use the 1939 MagDec map or the one for the present day? Since I don't know I will ignore it for now.
--- I know I am in the Baltic Sea somewhere on a bearing of 315o from mouth of Memal Harbor.
--- I am E of Greenwich, so I will be somewhere in the E latitudes.
--- I have been traveling 315o bearing for 8 hrs. @ ~10kts. = ~80NM. Given I am traveling forty-five degrees (N headway equals W headway) we can assume I have traveled half the ~80NM north and half west.
--- Since the mouth to the Memal Harbor is roughly N55o 43'. Traveling 40NM to the N and 40NM to the W would place the sub at N56o 39' E019o 22' by DR.
Does the above make sense, or am I missing something?
Next, let's take a shot of Polaris...
--- Elevation - Polaris @ 56o 12.5'
--- Local Time - August 31, 1939 21:00 "A" Time zone (GMT+1).
Calculate our SHT position...
--- SHT GMT = August 31, 1939 20:00 (8:00 hrs past GMT Noon).
--- Since it is Polaris, the elevation equals latitude.
--- SHT Local = Noon GMT in Greenwich + 9:00 hrs. 9.0 Hrs x (360o/24 = 15o/Hr) = 9.0 x 15o = 135o W
So our present SHT position would be N56o 12.5' W135o 0'. This can't be correct. It is 3900+NM away from my DR position on a bearing of 344o. 7NM pff the coast of southern Alaska. What did I do wrong??
Calculate our NST position...
--- Polaris same as above.
--- NST Local = Unknown other than what can be calculated from NST GMT (presently 18:00) which would equal 19:00. So, Noon GMT in Greenwich + 6:00 hrs. 6.0 Hrs x (360o/24 = 15o/Hr) = 6.0 x 15o = 90o W.
So our present NST position would be N56o 12.5' W090o 0'. This also can't be correct. It is 3200+NM away from my DR position on a bearing of 319o. This is near the borders of the Canadian provinces of Manitoba and Ontario, just south of the Hudson Bay. This is driving me bats! What did I do wrong??
I hope this helps?
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