About this detail of the Tiger
The turret that was designed for the Tiger (P) had a roof made of multiple armour plates. At each side, the roof slanted gently ffrom back to front, but in the middle it had a raised section, flat at the rear [3] . This central section allowed the gun to depress.
This turret design was modified in many ways when it was carried over to the Tiger E. The central section was extended to cover the entire turret, giving a single roof plate that was flat at the rear and slanted at the front. On the underside of this new roof plate two steel beams were welded, running from back to front [4] . It is possible that they correspond to the walls of the original raised section. Their new purpose was probably to strengthen the roof.
A profile of the beams, looking forward, is shown in this diagram. The roof plate is 25mm thick. The beams are simple flat strips, not I-beams [5] .
This diagram shows the right-hand beam, as seen from the center of the turret looking right. The beams do not run all the way to meet the front armour, because the roof has a 40mm strip at the front. The photograph shows the beams and the 40mm strip within the Tiger at Bovington Musueum.
Taken in the same tank, this photo shows that the rear ends of the beams were welded to the turret's rear wall.
[1] Survey of Tiger 250031 at Koblenz, by Hilary Louis Doyle
[2] Survey of Tiger 250031, by Stephan Vogt
[3] DW to Tiger 1
[5] Survey of Tiger 250122, at Bovington museum, by David Byrden
[6] Survey of vehicle 251114, at Saumur, by Jean-Charles Breucque