Complex sentence: The "Potosi" was manned by a crew of 40-44 and the fastest P-liner next to the five-masted full-rigged ship "Preußen" which was a little faster reaching speeds of more than 20 knots.
Split into simpler sentences: The "Potosi" was manned by a crew of 40-44. She was the fastest P-liner apart from the five-masted fully-rigged ship "Preußen", reaching speeds of more than 20 knots.