Daniel,

I see no evidence they were ever translated. Remember the British didn't capture just the WWI U-boat KTBs, they got it all -- all of the WWI KTBs, all of the pre-WWI material, the bwteeen war stuff and the WWII KTBs. There's an awful lot of material there (an estimated 600 medium-sized wooden crates worth). On microfilm, it came to 4,061 rolls (1,624 rolls being 1920 and earlier) -- not everything was microfilmed.

The first researcher that I'm aware of that had access was Robert Grant in the mid to late 1960s -- he used some of it in preparing "U-Boat Intelligence" (itself one of the most important works on WWI U-boat operations and losses, with lot sof new material).

It's also important to keep in mind exactly how far WWI naval research got before WWII. The answer essentially is "not far enough." Spindler IV, which covers February - December 1917, only came out in 1940 (or so). Volume V, which covers 1918, appeared in 1966. It's not very surprising then that research interest flowed to the more recent war.

Also, while KTBs are certainly critical items, there are a lot of other sources that researchers use that aren't in German.

Best wishes,
Michael