But what does everyone mean by a "gallery deck", and what do you believe existed there?
And in part this brings us back to the differences in carrier construction between USN & RN.
In the Illustrious class and successive armoured carrier designs, the beams supporting the flight deck were sufficiently deep that there was space between them at the "upper gallery deck" level which was used in part at least for various purposes.
In the 'closed' hangar overhead area between those beams of the Illustrious class that included, in various places, store rooms, a parachute packing room and a compartment forward for the accelerator / catapult gear. Forward of the hangar and lift well were crew accommodation and recreation spaces, while aft of the after lift were more stores, squadron offices etc. Between the hangar walls and the ship's side the space at this level was put to other uses.
There was also a "lower gallery deck" at about half hangar height, with compartments fore and aft the hangar & along its sides.
When Victorious was reconstructed, the "Upper Gallery Deck No.2" was used almost entirely along its length for crew accommodation.
Looking at the deck plan of CV-11 Intrepid of the Essex class as completed, only part of the "Gallery Deck" was used. Virtually all of the space at that level aft of the after lift was unused and open to the hangar as was most of the area between the island and the forward lift. These were the areas which I assume would have been used to suspend the spare aircraft intended to be carried in the original design. The latter practice was discontinued in US carriers in late 1942, as it was found to be a fire hazard. Very little of the remaining space was taken up with crew acomodation (a bit forward of the forward lift and another for senior officers abreast the island). Most was squadron offices, stores, ready rooms and other compartments necessary for the air group.
