Best way to target enemy vessels?

I have noticed that when doing manual firing orders, unless you specify in the next turn to change firing coordinates, the gun will fire at the same position turn after turn. When you're captaining a ship with 8 guns, it becomes a massive pain to have to reassign targets to every gun every turn. Is there a better way of doing this? Autofire may work, but as in How does autofire work?, auto fire doesn't seem to operate on optimal efficiency.