Why were HMS Tiger's two after turrets placed so far apart?
Short answerThe spacing accommodated the boiler, turbine, and propeller-shaft arrangement inside the hull, and moving the turrets would require rebuilding much of the ship.
NotesThe boilers sit around the funnel spaces while turbine and shaft lines need room farther aft. Placing machinery between the turrets allows the inner and outer shafting arrangements to pass through the hull. The resulting silhouette follows propulsion layout rather than aesthetics. Moving X turret aft beside Y turret to free deck space would require major structural work, amounting to a rebuild rather than a simple rearrangement.