I found a reference to this vessel in a KM memoir (draft at this stage) I recently given, and thought it might be of interest. http://strangevehicles.greyfalcon.us/AVISO%20GRILLE.htm
Apparently life on board could be stressful for VIPs. Interrogated after capture by the US Navy in July 1943, Kapitänleutnant Klaus Bargsten, sole survivor of U-521, reminisced about serving as a midshipman on Grille. Once, he said, when a group of these 'Olympians' was on board, an orchestra was playing for their entertainment, but the ship's ventilator fans were making so much noise that the music could scarcely be heard. Göbbels complained to the captain in his usual high-handed manner, ordering him to do something about it. The captain, while engaging Göbbels in conversation, managed to back him into position in front of one of the ventilators. When he gave the order for the ventilators to be shut off, the shutter gave Göbbels a resounding whack on the backside.
Bargsten also spoke somewhat heretically about the alcoholic habits of the Nazi great. Hitler, he said, objected strenuously to drinking and often gave his staff violent temperance lectures. Shortly after having been subjected to one such harangue on board the Grille, the staff gathered in the saloon to sooth their frayed nerves with a bottle of Champagne. Suddenly Hitler appeared in the doorway and the bottle, which had just been opened, was discreetly hidden beneath a table. Hitler strode into the room, kicked the bottle, spilling its contents, turned on his heel, and walked out without uttering a word.