Starship Cannons

The cannons onboard a starship are primarily meant to defend against pirates and other attackers. Military starships are often built with more and stronger cannons than those on regular ships, but they function in much the same fashion as the standard cannon at the basic level.
The cannon is installed on both the port and starboard sides of the ship, some ships also having two that face forward. Charges, often called cannonballs, are loaded into the cannon through a hatch in the back-right side. This hatch is then closed and sealed, and the cannon is ready to fire. It is then aimed by a gunner stationed in the gunroom, typically under the direction of the head gunner who has access to a more complete map than the gunners are able to see, and fired at the attacking ship by pressing down on a pedal attached to the base of the gunner chairs with both feet.
A blast of energy then hits the cannonball, sending it hurtling through the Void at high speeds. When it hits the target, it will shatter and, depending on the type of cannonball it is, a variety of things may happen. Some will set fire to the attacking ship, others will send out a pulse of electricity meant to disable some of the attacker's systems. Other still will not explode upon impact and are instead meant to remain solid, destroying some of the ship's hull. It has also been reported that there are cannonballs meant to implant trackers on the ships they hit, allowing pirates and such to target them more easily. Or, if used my the Spacefleet, these may be to track down pirates who escape in the heat of battle.
Maintenance of cannons is incredibly important if one wishes to keep them working in case of pirate attack. You must clean them out after the battle is finished, making sure that there are no shed bits of charges left lingering in the works. You must also be sure to check that every piece still moves and functions as it is supposed to, as it is not unheard of for cannonballs to damage the interiors of the cannons they are launched from. This does not happen often, but if not caught, you may risk your cannon exploding the next time to attempt to fire it. 
It is NOT advised for anyone who is not an expert to design their own "homebrew" cannonballs. Any damage caused to your ship, your crew, or your cannons because of these unofficial devices is not the responsibility of the company who built your ship, or who installed your cannons. "Homebrew" cannonballs are used entirely at the user's own risk.