About this detail of the Tiger
The driver and radio operator of the Tiger 1 were provided with hatches for their positions in the hull. These hatches opened outward on a hinged arm, and would lock in the fully open position.
The diagram above shows the positions of the hatches in the hull top relative to the center line. Each hatch is located 900mm from the vehicle center, which puts it halfway above the sponson, not above the crewman! This position was used so that the hatches would not foul the turret. Using these hatches must have required some contortions!
The diagram also shows some indents in the hull top surrounding the hatches. These indents, which were very shallow, are the tops of flat-tailed bolts. The three large bolts held the hinge for the hatch arm. The three small bolts around the hatch held latches with screws that were used to tighten the hatches for underwater travel.
Photographs  show that when the Bovington vehicle was captured, these latches were missing although their bolts were present in the hull roof. Also, the hatches of this tank did not have the necessary hooks to engage the latches. This could be the result of production difficulties, among other things.
The deletion of underwater capability from the tank's design meant that eventually the smaller bolts disappeared from the hull top. The hatches then resembled the above diagram.
A vertical periscope was installed in each hatch, starting with vehicle #1  . A 155mm steel cover was welded on to protect the periscope. The above diagrams show the dimensions of the cover.