About this detail of the Tiger
The Tiger's engine was water-cooled, and heat was extracted from the water using two large radiators with two fans each. The fans, in the extreme rear of the hull, were driven by the engine through their own gearbox.
Two kinds of engine were used in Tigers, HL210 and HL230, and for each the gearbox arrangements were different. This page describes the fan drive for the HL230, which was different to the HL210 fan drive.
The large HL230 engine did not leave much room behind it, so a small gearbox for each fan was mounted on the side walls of the engine compartment. These gearboxes seem to have been mirror images of each other.
