The attack scenario on two ships that you describe is from an older thread/video. Try this.
If targets are on the same course or close to the same course and on running parallel, attack using the Easy AoB mod, taking on the faster target first. You can verify your solution on the Attack Map.
After torpedoes are away to the first target, swivel the periscope to the second, adjust the second target's speed on the TGT dial, reset range, and fire at it. (If you have time, check the Attack Map to verify the firing solution.)
After the torpedoes are away to the second target, swivel the periscope to the third target, adjust the TGT dial for its different speed and range, then fire.
I have nailed three targets in a single attack run with this method, but I haven't hit a fourth yet as it will probably require firing the entire quiver of loaded torpedoes with a 80 percent success ratio to take out four, plus you may have to return to the scene of the crime and finish any damaged ships with the deck gun.
