Ships:

Population:
Each ship type has a minimum population and a max population. The minimum population is required to staff the ship. The more workers the ship has the higher the efficiency of the ship. When in space if a ship becomes unstaffed the ship will trigger the AI to return to your warehouse. This ship cannot hold cargo and will jettison all cargo it has. If your fleet has no spaces to hold the cargo the cargo will be lost. 

Weapons:
Besides having built in weapons most ships have slots to equip weapons you build. There are different types of weapons you may equip. They all have different types, ranges and specialties. Only equipped weapons have the capability of attacking more than one tile away.

Equippable weapons have these stats

Delay – Some weapons, especially those with the longer range may have a delay. As of now delay does nothing.

Range – Some weapons have more than a one tile range.

Type – Different types of weapons such as energy and projectile weapons do damage differently. Energy weapons do extra damage against shields while projectile weapons do extra damage against hulls.

Base damage- The base damage for the weapon. There are damage modifier on certain systems depending on the weapon type.

Special – Some weapons have special abilities, this will be listed in the description.


Shields:
Shields heal a base of 1% of shielding per turn taken. Before the hull is damaged the shielding must be taken down.

Hulls:
Different hulls effect the ship's speed, cargo size, and hp. Some hulls have special protection against certain types of equipped weapons. 


Vision:
Different ships have different tile ranges that they can see, most ships have a range of 1 to 3 tiles around the ship.

Visibility:
This effects the miss rate in battle. Also the most visible ship in the fleet determines the fleet visibility. The less visibility a ship has the less of a chance of detection by scanners. A fleet that has 0% visibility can only be detected with special tools. Note that attacking causes the ships visibility to be temporarily increased by 25% for 5 minutes. So in battle ships with 75% or more are effectively %100 visible.
If the fleet is visible or not by sensors is calculated every 10 minutes, so reloading the screen does not help you find ships.

Speed: Ship speed affects the attack order of the ships, the faster ships attack first. Also slower ships have a harder time hitting faster ships. Ships tend to attack ships near their speed first. Faster ships intercept incoming fast ships and heavy slow ships find it easier to target heavy and slow ships. It will also affect the movement rate of the fleet see the fleet section.

Examples:
fleet with a fighter and a battleship vs a fighter and a battleship. Fighter will attack fighter and battleship a battleship.
fleet with a fighter  vs  a battleship. Fighters will likely all attack first, if enough damage is done killing the battleship without a scratch.

Other: Some ship abilities like cloak, sabotage, and camouflage are only available to fleets when all 
ships in the fleet have the ability.