Deck-edge lifts could improve aircraft handling and air-group capacity, but their off-centre weight imposed a stability penalty. Moving the lift and a loaded aircraft up one side of the hull required compensating displacement or ballast elsewhere. Because that corrective weight counted against standard displacement, it mattered especially under treaty limits. Royal Navy studies considered deck-edge lifts for the Illustrious class but rejected them when the expected gain did not justify the weight cost. Centreline lifts therefore represented a deliberate naval-architecture tradeoff rather than simple resistance to a newer arrangement.
Chapter · 17:50-19:53
Why deck-edge lifts carried a stability cost
Royal Navy studies treated deck-edge lifts as an aircraft-handling gain that had to be paid for in off-centre weight, ballast, and treaty displacement.