There was no recorded wreck at this location so it absolutely was described to the relevant authorities, including the Receiver in the Wreck (RoW). They were being considered superb boats. Over the war 8 have been sunk, 3 surrendered and were finally scrapped, and two ended up regarded as lacking. https://dantebbxum.goabroadblog.com/33239643/the-best-side-of-u31