Complex sentence: Approaching Rarotonga in the dark, Luckner saw a dark ship which he thought was an auxiliary cruiser, but in fact was a beached ship, von Luckner pressed on to the Fijian Wakaya Island, arriving after a voyage of 3,700 km in an open boat.
Split into simpler sentences: Approaching Rarotonga in the dark, von Luckner saw a dark ship which he thought was an auxiliary cruiser, but in fact was a beached ship. Von Luckner pressed on to the Fijian Wakaya Island, arriving after a voyage of in an open boat.