Complex sentence: Shortly after 23:00 (Norwegian time) the flotilla was spotted by the Norwegian patrol boat HNoMS Pol III. "Pol III" was set on fire by the German torpedo boat "Albatros", but succeeded in raising the alarm.
Split into simpler sentences: Shortly after 23:00 (Norwegian time) the flotilla was spotted by the Norwegian patrol boat "Pol III". The German torpedo boat "Albatros" attacked "Pol III" and set her on fire, but not before the Norwegian patrol boat raised the alarm.