From what I read, the captain was Old School. In all seriousness, he may have thought that after scuttling his ship in neutral territory, stealing the radar was an ungentlemanly thing to do.
Seems to me if he could scuttle the ship he could set charges on the Seetakt gear. But then again, I’m not an old-school Prussian Kriegsmariner.
MANY moons ago I saw this film on late-night television.
As best I can recall, it was a pretty good flick, with Peter Finch
playing Capt. Langsdorff.
Too bad it’s only available in Region 2 format DVD (at least at amazon)
The Battle of the River Plate
http://www.imdb.com/title/tt0048990/