Bow torpedo hatches.
The operation of the bow torpedo hatches, I assume, works as follows referring to my image below. The bowhatches are operated from inside by rotating rods and linkages marked red. At the end of the operationrod is, as very VIIC commonly used, a threaded part having a traveling nut which transfer the rotational movement to push/pull movement to an arm connected to the fulcrum of the pressureproof bowhatch of the torpedo tube. The bow torpedotubes have angled muzzles towards the submarine centerline, a detail sometimes omitted by modelbuilders. I guess the reason for this design is to make accommodation for the fulcrums and fairingdoors well out of the torpedotrack. Indeed the cross section of the angled muzzle makes an oval hatch opening and the hatch is, due to the manufacturing process, circular, however as the angle is relatively small I guess the difference is compensated by the hatch face packing tolerances.
Opposite the fulcrum of the hatch is a shaft attached to the hatch acting as a connection point for a double set of rods which ends in a sliding shoe in a slot on the inside of the fairing door. When the torpedohatch shuts, this linkage pull the fairingdoor in place making the bow fairing, when the hatch opens, the side moves in the fairingdoor slot and the links pushes the fairingdoor inwards and thus covers the bowhatch and fulcrum, hence the hatch, fulcrum and links are not visible.
Tore