The Tiger E was originally designed with a HL 210 engine. This engine was mounted on the center line of the hull, in the engine compartment at the rear.
For access to the bottom of the engine, two round holes were cut in the belly plate. This diagram shows the hull from below.
Steel cover plates were bolted into the holes, flush with the belly plate. They were 25mm thick, the same as the armour.
The holes were located between the floor struts and torsion bars.
When the HL 230 engine was introduced, the left-hand access hatch was replaced by a larger rectangular hatch.
[1] Survey of vehicle 250122, Bovington, by David Byrden
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