Boarding a ship can commence once a ships shields are down.
There are three types of troops used for boarding:
Infantry - Purely defensive unit Assault Troops - Purely offensive unit Commanders - Provide a bonus to defending or attacking troops
Any Infantry onboard the ship being boarded will need to be destroyed before a ship can be seized. Commanders are not taken into account for defense or offense if all assault troops or infantry have been destroyed. E.g. if the ship being boarded runs out of infantry, but still has commanders, the ship can be seized. If the boarding ship runs out of assault troops, but still has commanders, the boarding ship will not be able to continue the assault.
Boarding has the following limitations:
A ship with a captain onboard cannot be seized Stations cannot be boarded or seized (For now) Docked ships cannot be boarded
The formula for boarding is the following:
Attacker Damage = Number of assault troops * (Random number between 1 and 3 / 50) + (Number of attacking commanders (Random number between 2 and 5 / 50)
Defender Damage = Number of infantry * (Random number between 3 and 6 / 50) + (Number of defending commanders (Random number between 4 and 10 / 50)
Casualties are calculated the following way:
Number of Assault Troops - Defender Damage Number of Infantry - Attacker Damage