Actaully, I think this is what ttraveler wants:

He wants to shoot a torpedo directly ahead (0 degree gyroangle) and still be able to turn the periscope without it directly affecting his gyroangle.

Is that a correct assessment of your request?

If this is the case, then the solution is simple. Set your bearing to zero. Don't worry about setting speed, range, or AOB; I don't think it matters. The important thing is to leave your TDC button on green (as opposed to red). A green button will give you exactly what you want: a manual torpedo shot.

With this setting, you should be able to move the periscope around without it affecting the direction of the the torpedo shot.

At least that's what I think... I haven't tried it yet...

But it IS more useful to set your target speed to zero knots and use your periscope as an aiming device. "Firing from the hip" as it's called...

It's just IMHO, but firing "straight and center" is useless.

Markhimov: You're right except for the speed, you still need the speed at zero. Bearing 0, Speed zero, leave it in manual (green light) and there you have it. If the speed is nonzero (target is moving), the TDC will calculate the lead for it and the angle will not be straight ahead anymore. Therefore, speed is the #1 most important input for affecting gyroangle. With no speed, there's no need to lead the target.

Oh, you're right. :up: