Firing on the Roll
From The Dreadnought Project
Firing on the Roll was a gunnery technique by which a gunlayer or Director Layer would set his elevation to one such that the motion of his ship causes the crosshairs of his sighting telescope to sweep across the target and then leave it there. He would then wait until such time as the sight comes on and then fire the weapon.
This technique was one which produced a low rate of fire, as the weapon might sit idle for some time until the sea deigned to sweep the horizon to the suitable angle, but one which might be employed if clumsy hydraulic controls or similar limitations made a more agile laying of the weapon such as Continuous Aim or Hunting the Roll untenable.
