Don.
When you open the main starting supply airvalve, air is supplied to the starting air manifold. If you then put the startinghandle in the "umsteuer"/"reverse" position you open two valves in the airmanifold, 1. air supplyvalve to the "umsteuer schieber" or slide and 2. the ventingvalve. The air is supplied to the ahead/ astern "reversing" slide, which control the displacement piston for the camshaft. This means the engine is ready for maneuvering. The reversing slide is operated by the ahead/astern handle, removed on non reversible engines but you still see the rudiments. The slide has only two position, ahead or astern and. If at the starting operation the starting lever passes the revers position nothing happens as the air only keeps the reversing mechanism in the ahead/astern handles status quo position. Thus the starting handle has to be put in "umsteuer" position in order to be able to operate the ahead/astern handle on the direct reversible engine. Below I have tried to sketch (red) the diagram in the "umsteuer" (revers) configuration with the ahead/astern handle placed in ahead position . Further is a picture of the revers handle rudiments on the U-995 engines. Further to the basic movement, the reversing system consist of a number of interlocks preventing the handles to be moved at the wrong times, which I for simplification have omitted at this stage.
Tore
