Why did the Tiger-class light cruisers carry an amidships three-inch turret?
Short answerIt increased anti-aircraft coverage, allowing at least several mounts to engage from most approach angles.
NotesThe amidships three-inch anti-aircraft mount was far from useless. Its position helped create a diamond distribution of weapons around the ship. That geometry allowed several turrets to bear against aircraft approaching from different directions. The arrangement provided the broad coverage required by an air-defence cruiser.