Scoring hits with torpedoes is challanging, but not impossible. You have to be a little methodical, otherwise you'll just be wasting your time and energy if you just "wing it."

You can always hit with a direct bow attack, but, as in all cases, be careful to not to use any rudder at the time of release. Your nose should be aligned on the correct heading without skidding.
Here are some additional comments to the training writeup. I'll teach you how to fish instead of giving you a fish. Your reward for figuring out the aimpoint will be your ability to hit with torpedoes. I think that part of the game is exploring and figuring ways to derive answers to your problems.
1. Since you read the training writeup, you know that your target should be 41° off centerline, flying perpendicular to the fleet path at your release point just as the auto ack begins to fire at you using Allied torps (PT boats and TBM).
2. Your aim point from the cockpit depends on the field of view (FOV), which depends on your video resolution you have set for the game on your PC. You can find your FOV by clicking on the Video Settings tab of the first clipboard at game startup.

In the example below, my FOV is 106° for my resolution of 1920 x 1080.

We're interested in the horizontal resolution, the first number, so I have 960 pixels (1920 pixels/2=960) left and right of centerline, and my FOV is 53° (106°/2=53°) left and right.
3. My aim point of 41° is 77.4% of the way from the centerline (41°/53°=.774*100), or 743 pixels (960*.774=743) from centerline. It is also 217 pixels from either edge of my monitor (960-743=217).
Therefore, this is 217 pixels and how far off either edge of my monitor I align the target at release:

4. If you divide your horizontal resolution by your vertical resolution to get your display ratio, you can use this handy-dandy chart:
Ratio FOV
1.77 106°
1.66 103°
1.60 100°
1.33 90°
1.25 86°
Good luck and good hunting, er fishing!