Don,
As you know the U 995 was originally designed to be propelled by direct reversible GW engines hence the linkage with clutches are originally equipped with a number of interlocks no more applicable. Below is an image of the system where I have removed the superfluous reversing rudiments. The GW engines were as you know designed with a Roots blower pto from the camshaft and should be switched in at 390 rpm. The drive is shown on the image below. At a normal start the supercharger is disengaged. On the both engines there are two manifolds towards boardside, the upper for airinlet, the lower watercooled, for outlet. The outletmanifolds are connected via flanges to the cylindercover exhaustducts (with exhaust cages, watercooled). The airmanifold has flangeconnections to the separate airinlets in the cylinder cover. Further the air manifold has two inlets which can be shut by cylindrical slidevalves operated by the supercharger clutchhandle up front of the engine and to the Roots bloweroutlet, thus now an enclosed airsupply to the cylinders..
If revs are required above 390 the fuelfilling handle is pushed to a higher fuelfilling position, the supercharger clutchhandle at the outboard side pushed rotating the rod by bevelgear. The rotating rod continues after the air shutting valve where the rod is fixed to a 90 degrees bevelgear transferring the rotation to a rod with gearwheel which is engaging a tootrack, which is axially moved and thereby trigger the friction shoe of the friction clutch.
Tore