In the training the ships are neutral and therefore your WE won't attack them. You have to figure it out by yourself. As for flakgunners, they're always better shots than me

Let him handle it. Small hint, if you may: learn to use the deckgun as efficiently as possible. Contrary to the flakgunners , you're the best shot in the ship with it and you'll be saving lotsa ammo by using the deckgun yourself. Comes handy, when you have to take out the guns of armed merchants quickly enough.