Siege Commander

Combat

Under your leadership, the time required to assemble and move a siege engine is greatly reduced.

Prerequisite: Craft (siege weapon) 5 ranks, Knowledge (engineering) 5 ranks or Profession (siege engineer) 1 rank.

Benefit: When you lead a siege engine assembly crew, you grant all of its members a +4 competence bonus on checks to assemble or move the weapon. You also halve the time required to assemble a siege engine.

Source: Ultimate Combat