Don.
I checked to days Skizzenbuch on the Schnorchel which as far as the airpipe goes is OK.
I am not sure of your description on the homing of the Schnorchel though. The U 995 has many modification from the original and the schnorchel is a major one. The mast air valve is a hingefloat, original is a ringfloat, the schnorchel lockingpin drive rod from the control room is removed, the raising and lowering system is partly removed just to mention a few items. The schnorchel installation make use of the existing hydraulic system with a branch off and shutting valves from the periscope pipes. The mast is secured in a downright position by a locking clamp operated from inside the pressurehull portside up near the CO cabin. Likewise the mast is secured in the homing guide at the towercasing. This lockingpin is operated by a wheel connected to rods from the controlroom port side up. The transmissionrod have different positions at the various boats, some goes inside the towercasing, some partly inside or in an outside protector casing but all rodversions protrude outside the casing at the spraydeflector before they are engaging the locking device. I have tried to incorporate most of this in the image below the schematic sketches made by me are my assumptions which might deviate from the real design.
Tore
