What is the TDC/torpedo really doing?

[jbruns29]

A nuts and bolts type question. When using the fully manual mode you input the range, speed, and angle on bow data. This gets loaded to the TDC. You lock onto the ship with your periscope. If your abeam to the ship you fire when the gyroangle gets near 000. At least I do anyway. So what is happening between the TDC and the torpedo. Right before launch is it constantly updating the reuired speed of the torpedo for the torpedo to go to hit the target? But dont you set the speed(S/M/F)? Is it also telling it which way to steer? So if I shoot at a gyroangle of 45 degrees will it turn the torpedo into the target?

[jonmar]

I think it just calculates the lead required for you to hit the target. To do that it looks at the target's bearing, range, speed, AOB and the speed setting for your torpedo. And yeah if you fire before or after 000 gyroangle I think it will try to turn the torpedo to achieve the required lead angle on the target.

[Pisces]

The TDC calculates only the gyro angle for the torpedo, which is the relative bearing (from your bow) that the torpedo must turn to, to eventually be able to hit the target with the specified initial range, (peri/Uzo) bearing, speed and AOB, and set torpedo speed. (though there is a bug with changing torpedo selections set to different speeds. the lead isn't recalculated)

As the torpedo leaves the tube it first goes a short straight path, before it starts to make the turn. The displacement of the torpedo as it finishes the turn causes the gyroangle to be different from the initial periscope/uzo bearing. This is taken into account by the TDC, mostly based on range and bearing.

Aside from that it transfers the set depth to the torpedo.

And you can add a bit of a fudge/spread offset o the gyro angle with the salvo angle dial.

[jbruns29]

Thanks for the explanation!