Talk to your Watch Officer and tell him to Man the Deck Gun to get your sailors onto the gun.
To make it fire, scroll your mouse wheel to engage binoculars. Move the yellow cursor over a target and it will turn red. Press SPACEBAR to declare it a target. After a few moments the gun will start to shoot.
To man the gun yourself, climb down the ladder on the side of the conning tower.
After firing the deck gun, some one told me there is a quick way to get back to the coning tower without having to "walk" back up by pressing a certain key.
Sould anyone one enlighten me what key should I hit ??