[DicheBach]

I think I'm getting the hang of this American TDC . . . or rather "better" with it. Of course, if one indulges in all the unrealistic perks afforded by "Hard" mode, hitting is just a matter of constant flipping back and forth between the nav map and periscope. Still a challenge, but it gives an unfair advantage.

I haven't figured out how the actual periscope operator would determine the course of the target, and I would think the TDC would include features for that. But the way I do it (which is maybe only "partly" unrealistic).

I use either a visual contact (more realistic) or a sonar contact (possibly less realistic, but I notice those sonar prongs tend to be pretty far off of the ship blob determined visually, so maybe not so "unrealistic") and plot two dots at a sufficient time interval = enemy course and speed. This is ideally done with the target already on a more or less perpendicular course and closing toward the subs vector, maybe 2500 yards? That seems to be about what the TDC can lock on reliably even in ideal atmospheric and sea conditions . . . maybe 3250.

With those two bits, it can be done without going away from the periscope (now that I've tinkered with it to make sure how it works).

Assuming he doesn't change course and assuming the intersect of the two vessels course is in fact 90 degrees (and I would guess that having the sub at very low speed if not stopped is important to the math too): then the relative bearing in the periscope IS part of the equation for determining the AOB (this was what I had inferred based on the geometry, I mean hey . . . triangle can only have 180 degrees inside eh!?)

180 - 90 - Relative Bearing = Angle on the Bow.

With the speed already plugged in from the sonar/visual plot and assuming the courses remain the same it becomes a relatively simple matter.

1. Set AOB dial on the TDC to some future value based on the targets actual relative bearing right now. For example, if the middle of the target is at 60 relative bearing (actual AOB = 30 right now) then assume you'll be ready to make the shot in 10 or so more degrees (if he is going "medium" speed of 6 knots). So 90 - 50 = 40. Dial in 40 AOB.

2. Start taking range measures. Repeat every couple seconds so you're confident you are in the ballpark. Try to time one last range measure with the stadimeter when the middle of the target is at about 48 or 49 bearing.

3. Fire one.

4. Dial the AOB up a few degrees (maybe 45). Take another range measure.

5. Fire two.

I had one perfect setup in a career (glassy seas clear night one old fast merchant at 6 knots going almost exactly south into the Surabaya harbor) and I replayed that a couple times and managed to get 3 hits in a row using that method.

I'm still not sure the "Position Keeper" is that useful, but it does seem to adjust the AOB so I may experiment with it too.

With the Position Keeper you could replace step two with:

2. When you get a range measurement you are confident of and with the relative bearing very close to what you had "predialed" for corresponding AOB. Hit Position Keeper.

3, etc. Just starting firing at intervals

I guess there was some sort of an socket that connected the TDC to each torp? The TDC must've had a bunch of gears and cogs in it that calculated this ****, and would adjust settings based on the last readings when Position Keeper was set. At the moment fire tube command was given, the last set of data from the TDC set the gyro on the torp to correspond to what the current position keeper values were?