Combat Strength is the raw measure of a ship's power. It is calculated as follows:
Combat Strength = (Health + Shields) x DPS
This is in line with the belief that an effective ship needs to be both durable and damaging. Too fragile, and it won't be able to deal much damage before being destroyed; too little firepower, and it will barely scratch the paint of your enemies.
Let's use this concept on the Pathfinder Corvette. This ship has 5 t unladen mass and 40 t maximum mass, leaving 35 t to spare. As a result, only the following equipment can be used:
|Pulse Ray I||10 t||3||Plasteel I||10 t||25|
|Pulse Ray II||20 t||5||Plasteel II||20 t||50|
|Disruptor Ray I||30 t||10||---||---||---|
With respect to mass restrictions, we get the following possible combinations of ship builds:
|(1) Pulse Ray I + Plasteel I||25 t||3||33||3 x 33 = 99|
|(2) Pulse Ray II + Plasteel I||35 t||5||33||5 x 33 = 165|
|(3) Pulse Ray I + Plasteel II||35 t||3||58||3 x 58 = 174|
|(4) Disruptor Ray I + No Armor||35 t||10||8||10 x 8 = 80|
Evidently, (3) has the highest Combat Strength, and is hence the best Pathfinder Corvette build. Note that (1) is actually stronger than (4), despite using up less mass. This highlights the importance of having durable ships and not just focusing on damage output.
Note that Combat Strength is only a partial measure of a ship's overall effectiveness. Read here for more details.
The Combat Strength of a fleet is determined by its total health, shields and damage output, rather than the sum of each ship's Combat Strength.
For fleets with multiple ship classes (so-called mixed fleets), it is important to specialize each ship with respect to their class, such as using heavy armor on cruisers because they gain an armor mass reduction when upgraded, and using heavy weapons on battleships for a similar reason. While this may weaken each ship individually, the fleet as a whole can achieve higher Combat Strength as the fleet mass is used more efficiently. However, this does not apply to pure fleets because only either defense or offense can be enhanced in this way, not both.