Vepr157 wrote:
I don't think Alberich was necessarily applied to the snorkel (you may be thinking of the radar-absorbing coatings that were). Alberich absorbed active sonar, so the entire hull would have been covered. Since the snorkel is so small compared to the size of the hull, it would not have been particularly important to cover it in the Alberich tiles.
The book at the beginning of the thread is a good reference for the Type XXI. I can also recommend Rössler's U-boottyp XXI.
Jacob
the conning tower would've also be covered right?