AoB is important but so is speed. The two form an important tandem in your solution. Range itself isnt as important. However being off by a fair bit in speed or AoB can throw everything off.
Also, yes the TDC does automatically track the target based on where you point your periscope. Once you set AoB you've told the computer the course that the ship is sailing on and it calculates the ship's position and the gyro angle based on where the scope is pointed. This is how you can aim at particular parts of the ship. This is also how you can fire at multiple targets in a convoy. Although you'd need to adjust range for every ship. Once you enter AoB, so long as the target ship remains on its original course it will accurately predict the correct targeting solution.
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