[Von Due]

To put L = 28m to the test, and assuming the reach and turn radius in game were historically accurate or close, I did this test:

Using L = 28 meters, R = 9.5 meters and r = 95 meters.

L + R = 37.5m.

I drew a line on the map straight up for 3000 meter using Pato's bearing and range tool. This line represents the Bp line of sight to P at a distance of 3000m (the line OP in the illustration above).

From the 0m end of the first line, I drew a horizontal line line and marked a point approximately 37 meters from the start, again using Pato's tool and counting the pixels (the vertical line in the illustration, and marking the end of the reach measured from the periscope at 0m).

From this mark, I drew a line approximately 95 meters long straight north. At the end of this line I then drew a circle that now had a 95m radius (the circle and horizontal radius line in the illustration).

From P at the far end of the 3000m line, I drew a tangent line for the gyro angle. Pato's bearing tool showed this line having a bearing of approximately 2.5 degrees (corresponds to the angle i) and the gyro angle g being approximately 92.5 degrees.

This is a very uplifting result as this agrees within the inaccuracies of the drawing and measurements to about 0.1-0.2 degree from what the TDC gives me for the same bearing and range.

It does appear more likely now that the game uses actual dimensions and that one could construct on the map the triangle for gyro angles at any arbitrary Bp and D.

EDIT: Repeated the test with L being my initial guess of 33.5. Changed the position of the reach and the center of the circle accordingly.

The difference for D = 3000 meters was too small to be meaningful but for D = 2000m the result was a closer match between the drawned angle and the TDC computed angle when L was 33.5. This suggests that 33.5 is closer to the length the game uses.