Just to clarify, since a couple people now appear to have commented on my statement about the 90° target bearing standard approach; it has nothing to do with a 120° approach to the target true course.
It's just the standard approach an XO would take by putting the target bearing on a 90° beam moving (presumably) in the same relative direction (at this point AoB is an unknown). Then the captain would be informed... and then perhaps after an observation (or several) an AoB determination can be made and then maybe a 120° to TC would be the prefered approach angle for attack.
Okane mentions in Wahoo that as the XO he puts the boat on a standard 90° approach and then informs Morton of the situation. It's a method that's also documented as the standard approach in the torpedo fire control manual. It doesn't mean that you're on any particular approach angle to the target true course.
It looks like this:
The standard 90° approach for target M1 or M2 is 330° and we don't really know what the true course is yet for either one.
This is a first contact (and probably at considerable distance) approach. Granted I've exagerated the M2 contact here because in this case we wouldn't actually be closing (approaching) on the target. I should probably redraw it with an acute angle, but I don't feel like doing it again...