Here is some additional information that will provide deeper understanding of Bastion mode game mechanics.

The mode is available for Level X battles (Tier VIII, IX and X ships).
There are certain capture sectors for onshore installations on a map. While these sectors are neutral, the installations do not participate in a battle. Once captured, they start to provide fire support and intelligence service to the team who controls them.
‘The Atlantic’ – the only map where Bastion mode is currently available – provides two possible settings for capture sectors: sectors 3 and 4. They are chosen randomly.
Forts and Surveillance stations lose health points when they are hit with main guns, secondary guns and bombs. Dealing damage to Forts and Surveillance stations causes the loss of capture status of sectors they belong to and brings additional domination score to the team.
When a Fort or Surveillance station runs out of health points, it is considered conquered.
Conquered objects will temporarily be unable to participate in battle and will gradually recover their health points. Once they have recovered, they will function as normal.
If Fort or Surveillance stations located in enemy territory are conquered, the sector becomes neutral.
Forts and Surveillance stations have simplified damage models without armour and fire. Any hit affects the object as a whole.
Forts attack enemy ships at the shortest distance to them.
Forts equipped with 406 mm artillery guns and 80 mm AA-guns. The type of shells (AP or HE) is chosen randomly.
Forts have limited field of view, which is why they perform best when working in tandem with a Surveillance station. Surveillance stations are able to locate enemy ships and aircraft, but not torpedoes.
Forts have certain sectors of fire and dead zones where they cannot shoot enemy’s ships.