Operation ZZ order?


In his orders for Operation ZZ (the surrender of the German High Seas Fleet) Admiral Beatty decreed : "Before meeting the German Fleet, and until the signal is made to negative it, ships' companies are to be at "CB" stations.
Turrets and guns are to be kept in the securing positions, but free. Guns are to be empty with cages up and loaded ready for ramming home.
Directors and armoured towers are to be trained on."
Does anyone know what "CB" stations meant? Closed Battle perhaps? And what did that mean in 1918?