[Aktungbby]

This or the engineer told them some serious BS

It is entirely possible that the crew was intentionally misinforming their captors. My source was the interrogation report without comment as to veracity by the interrogators. http://www.uboatarchive.net/U-570/U-570INT.htm The date 1941 was early in the war and U-boat crews were not yet demoralized and 'spilling their guts'... lucky to be alive. From the same report:

The chief petty officers, and to a lesser extent, some of the petty officers, expressed great concern at the inadequacy of the training and the lack of U-Boat experience, not only of the men, but also of the officers and petty officers; no attempt was made to disguise the incompetence of the crew and the officers were severely criticised by all the men. The impression gained was that the morale of the ratings was high at first, as they had been filled with clever propaganda about the glammour of belonging to the crew of a U-Boat, and they had little or no realisation of active service conditions; many were helplessly seasick, and, at the first sign of real action, they gave way to panic and became useless, admitting later that they were, in point of fact, glad to be out of the war; they were somewhat childish in many ways and appeared to have forgotten their recent escape from death, as they became interested in and curious about their immediate future prospects. The senior petty officers, having been somewhat depressed from the outset and consequently of lower morale, would have been prepared to put up more of a fight, had they had any confidence in their captain or other officers. The Chief Quartermaster, by far the most competent man in the U-Boat, appeared to have been systematically overworked for many months; he complained that he had only been home on leave once since the outbreak of the war. Like all German prisoners of war captured for many months they were extremely security-conscious as a result of repeated lectures on the attitude to be adopted if taken prisoners. The success of this measure has reduced the information obtained from prisoners and has made interrogation very much more difficult.

@ Catfish: BS is short for ...U-know-what and thus expressly forbidden by FAQ's IN this case! The proper espionage term is Misinformation GEN 'Stormin" Norman Schwarzkopf, himself a master of misinformation, famously got around the BS issue in a press interview..."Bovine Scatology" is however, perfectly permissible!