The gunner being the key reminds me a lot of this amazing sequence in a very different, but also very similar, type of battle. Spoilers in case you haven't seen the movie, which is fantastic.
The key to the entire engagement is to take out the enemy's mainmast, and as they rake the ship with broadsides the XO himself takes control of the last gun to make sure that it hits its mark.
The entire battle is just genius, from the initial salvos to the storming of the enemy ship, which the captain himself of course leads, being the first to jump on the enemy ship, and then culminating in the counter attack by the French gunners who try to sink the British ship by firing below the waterline, which has to be repelled. Grand stuff.