Sir Winston Churchill got it wrong, and so did C.S. Forester.
The attempt to enter Scapa Flow at the end of October 1918 was made by Kapitan-Leutnant Hans-Joachim Emsmann in UB116. His doing so was approved by the Wilhelmshaven U-boat Fuhrer Michelsen, and the boat was manned by its regular crew augmented only by one officer, name of Schutz, who’d sailed before with Emsmann.
In both World Crisis and The Gathering Storm, Churchill wrote that the U-boat was manned by a crew of officer volunteers, and Forester’s play, U.97, made the same mistake, albeit in (presumably) a fictional treatment. But although the German High Seas Fleet had mutinied, the U-boat arm had not; no officers-only crew would have been needed or probably even thought of. Former submarine officers would agree with me, I think, that the performance of any such scratch crew might not have been all that impressive, either.
As far as I know, Forester’s play was never staged in its original form; only after being re-written by a German, Karl Lerbs, and re-entitled Germany, was it put on in Bremen and Hamburg in the autumn of 1931. According to German reports it was well received. I have not read it or even seen it, but again, going by a German review of that time, it seems that the fictional crew meet their deaths through oxygen starvation, not by being blown up in a shore-controlled minefield, as was the case. I should add to this, however, that Kapitan-Leutnant Emsmann’s forlorn sortie only gave me the idea for Stark Realities, which is fiction from start to finish and only in the broadest sense a reconstruction of the historical event.