The Frost Keep and the Ember Keep: sieges, towers, raising and rebuilding them, and the holders' rewards.
Every sea with captain fights has a fort: Frost Keep in the Northern Ice Sea, Ember Keep in the Fire Isles. It stands 2,450 px from the harbor, where the middle and outer waters meet, with two gates and 6 towers on its wall. Forts are fleet business: you need a fleet to take and hold one. Fleets
Towers fire on every ship not of the holding fleet; on everyone while the fort is nobody's.
When the last tower sinks, the fort goes to the fleet that did the most damage to the towers; within seconds every tower rises again in the new holder's colours.
A siege nobody presses for 5 minutes is forgotten.
In a fort held by nobody, a fallen tower rises again after 10 minutes while others still stand.
A held fort with no tower standing is open: another fleet that keeps its lagoon for 2 minutes, with none of the holders inside, takes it.
A capture is announced to the whole server; when your fort is attacked, your fleet is told.
The holding fleet raises its towers from inside the walls.
Sunk towers of a held fort don't rise by themselves: the fleet's captain builds them again from inside the walls for gold (Frost Keep 200,000, Ember Keep 350,000). It stands at level 1 after 6 minutes.
Towers mend very slowly when nobody has hit them for 60 seconds and a fleet mate is in the lagoon (about 11 minutes to full).
Every sunk tower leaves 900 XP, 3,000 gold (more for higher towers) and 3 crystals.