Complex sentence: During the winter the passengers remained on board the "Mayflower", suffering an outbreak of a contagious disease described as a mixture of scurvy, pneumonia and tuberculosis When it ended, there were only 53 passengers, just more than half, still alive.
Split into simpler sentences: During the winter the passengers remained on board the "Mayflower", suffering an outbreak of a contagious disease described as a mixture of scurvy, pneumonia and tuberculosis. When winter ended, there were only 53 passengers, just over half of the original number, still alive.