First off, I'm glad to see interest in the Is-Was I made; I hope it helps people enjoy SH 4 even more.
Regarding transparency, the original had both the C and Periscope dials clear, but after your comments, I don't see why the C dial couldn't be printed on paper. But the Periscope dial must be clear so that you can see the values underneath.
The way I believe the wheel works is like this. Prior to a ship sighting, the A and B dials can be pre-set together to your heading, with the "0" degrees mark of the A dial representing the front of the ship, and the B dial showing true heading of the ship, by placing the heading value at the A dial "0" degrees mark. So if you're heading due east (90 degrees), then the A dial "0" degrees mark = the B dial "90" degrees mark.
So let's say you're traveling due east, 90 degrees. Then suddenly, you get a ship contact (Via sonar, periscope, etc. It doesn't matter). "Sir, new contact, 300 degrees relative!" What I do is I move the Periscope dial so that the triangle is over the A dial "300" degree mark. This is also equal to a B dial value of "30" degrees. The B dial can now tell you what true heading to take if you want to head straight for the contact. "Helm, make new course 30 degrees".
But let's pretend you don't change course. Ok, now the last bit of the puzzle is Angle on the Bow. You have two ways to use this. First, if you can determine the true course of the contact via plotting, you can input the contact's heading to determine AoB. "Sir, contact heading is plotted out to be 330 degrees!" You do not move the A, B, and Periscope dials; you move the C dial until the "0" degrees mark of the C dial is pointing to the "300" degrees mark of the B dial. When you do this, you look at the Periscope dial marker 180 degrees opposite the Periscope triangle. This marker points at "120", on the left side of the C dial ship, so this tells you that the contact AoB is 120 degrees port.
On the other hand, let's say you visually estimate the AoB, and decide it to be 100 degrees port. You move the C dial "100" port value so that it matches up with the Periscope dial marker that is 180 degrees opposite the triangle. When this is done, you can then determine via the B dial that the contact's heading is 310 degrees true.
Once this is done, you decide to make a direction change, and head straight for him. You do not move the B, C, or Periscope dial; instead, you just move the A dial so that the "0" value matches up with the Periscope marker that you had already preset above.
That's probably a way-too-verbose answer, but I hope it helps. I suggest playing around with it for a while, and eventually you'll get the hang of it. Good luck!
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