There was no recorded wreck at this locale so it had been noted towards the applicable authorities, such as the Receiver from the Wreck (RoW). They were being considered exceptional boats. During the war 8 were sunk, 3 surrendered and were inevitably scrapped, and two have been thought of missing. https://hectorrwyyu.thechapblog.com/33273445/the-basic-principles-of-u31