According to Wikipedia:

“Instead of a single island superstructure containing both the ships' navigation bridges and flying control (flyco) centres, the ships will have these operations divided between two structures, with the forward island for navigation and the aft island for controlling flying operations.<56> The primary reason for having twin islands was to space out the funnels, as the ships were designed with redundancy with "duplicated main and secondary machinery in two complexes with independent uptakes and downtakes in each of the two islands", while the alternative of consolidating all the exhaust trunkings would have reduced hangar space as well as increasing the vulnerability to flooding. There are also additional benefits to having separate islands rather than a single large island, such as easier construction, reduced wind turbulence, and freed up deck space. Using two structures provides separate mountings for the air surveillance radar (forward), which does not interfere with the medium range radar (aft); furthermore, visibility is improved for both navigation and landing operations.<57>”

Given the prior Illustrious-class carriers had multiple funnels all in a line, making a stretched-out island along the side of the Carrier, I guess they wanted to group them together and have space for an extra elevator.

—- Philip

	Philip J. Moyer Contributing Writer, Editor and Artist (and Moderator) -- Eyrie Productions, Unlimited CEO of MTS, High Poobah Of Artwork, and High Priest Of the Church Of Aerianne -- Magnetic Terrapin Studios "Insert Pithy Comment Here" Fandoms -- Fanart -- Fan Meta Discussions