Complex sentence: It was not all over yet, as "U- 230" found, the Bay of Biscay was a hazardous area for U-boats, having to constantly crash-dive because of marauding British aircraft.
Split into simpler sentences: It was not all over yet however, as "U- 230" found. The Bay of Biscay was a hazardous area for U-boats, having to constantly crash-dive because of marauding British aircraft.