Chris,

There's a lot here.

UC 78 would not be the answer. It only arrived in Flanders on January 19, 1918. Her first patrol from Flanders only came on January 25th and was to the English east coast – a standard work-up pattern for new boats to the command.

I can't find Schwedrt-Fege in the "Ehrenrangliste," so presumably either an army officer or a misspelled name ( maybe something like Schwerdtfege but still no match in the "Ehrenrangliste").

For now, the HMS Zubian sinking claim for UC 50 on February 4, 1918 is the standard, postwar British claim. The maximum patrol length for a Flanders UCII patrol through Dover however was only 20 days, which is a major red flag. Luckily, we don't need to rely upon that to reject the Zubian sinking claim, as Zubian's attack was clearly against the homebound UC 79. (Clear match in UC 79's KTB.) Robert Grant was the first to notice this, and it's in his 1969 book "U-boat Intelligence."

What actually happened to UC 50 is very unclear. It's one of the two most missing of the Flanders-based submarines that did not return from patrol. By most missing, I mean that at this point, all we can say is that it sailed and did not return. In most other cases of missing Flanders-based U-boats we at least have some contact with after they sailed (typically a ship sinking).

Unfortunately, we aren't going to be able to use ship sinkings to determine whether UC 50 got to her assigned patrol area in the Bay of Biscay. Uc 50's patrol area overlapped with that of the larger U 84 and U 93, neither of which returned to patrol. While some attacks on shipping were clearly conducted by U 93 or U 84 (and in one case clearly by U 93), there aren't any cases that are clearly attributable to UC 50 (there are no survivor statements describing a UCII) but that may not mean much as several ships were torpedoed without the U-boat being observed.

I won't read anything to there not being a mention to a rescue operation in UC 50's KTB. Such special operations were often not mentioned or mentioned only cryptically.

FWIW, the wreck of U 84 was found off Penmarch a couple of years ago. What is probably U 93 is in the eastern English Channel. The cause of loss of both boats is not obvious.

Best wishes,
Michael