An example of a typical gunnery bridge
The aft portion of the same bridge
Examples in figure above.
The helm sign is to the left, and looks like a wheel. Right or left clicking this sign will turn the craft that direction. You can create this sign by writing “[Helm]” on the first line of a sign.
The Cruise: OFF sign enables straight line movement at maximum speed. It can be created by writing “Cruise: OFF” on the first line, and activated by right clicking the sign.
The Cannon Director and AA Director allow you to aim TNT cannons and firecharge dispensers (respectively) towards where you are looking when holding a stick.
The Remote Sign / Main Gun allows you to remotely turn turrets (If you make a turret using Subcraft Rotate / Turret / X then a Remote Sign with Remote Sign / X written on it will work like a helm sign for that turret. Turrets merge to certain armor blocks, most redstone components (not redstone torches) and light grey wool. Use them to make turnable guns!
Ship pilot signs can be created by writing the .craft string on the first line. Those strings can be found here.
You can control a ship with a stick. By right clicking in any direction with a stick, you can move your craft in that direction by 1 m/s. Use this for fine control. To diagonally cruise, left click to enter direct control mode (right clicking will cause you to ascend, shift right clicking will descend) and select hotbar 4 or 6 to diagonally cruise in those directions.
You can also make Ascend: OFF and Descend: OFF signs to ascend or descend at cruise speed. You can type /release to un-pilot a craft.
A "single-action" small-caliber design
TNT Cannons are typical armament of this server. Certain craft types require different gun designs to function correctly -- a naval ship will not use the same gun as a tank or an airship. A craft at sea level may need special weaponry to hit targets far above them.
For example, a navy ship requires either a lava chamber or a specialized naval gun which dispenses its own water into the propellant chamber. An airship or tank do not require this mechanic. A subairship may require a mortar or a high arcing cannon. Each of these require their own unique design considerations.
To your right is an airship equipped with a more standard gun variety. It is recommended that you talk with a more experienced engineer when designing your first weapons.
A calculator for a more standard list of gun sizes and calibers is linked here.
A heavy cruiser design, courtesy of Yguy9