They only got 4 out of 118 that they had parts produced for seaworthy! Unbelievable that they could have produced so many high-tech boats while being bombed day and night.
I was prompted to do more research on this particular sinking by noting that 75 sailors were lost as opposed to the usual 50 or so indicating a much larger boat.
I seem to remember some time ago slave laborers at Peenemunde were passing on information to Allied intel.