Were there any u-boats operational during the Second World War that are still unaccounted for? If so, were there sightings of these vessels after they left port or did they just vanish never to be seen again? Where did they sail from, what was their number, who was in command? What was their cargo? Please help, I am writing a novel and this sort of information, no matter how vague could be very important. I would be very appreciative and credits will be given should the story make it into print.