How did Kit's parents die in The Witch of Blackbird Pond?

The reader learns about the fate of Kit's parents during a conversation she has with John Holbrook in the second chapter of The Witch of Blackbird Pond.  Holbrook asks Kit about her parents, and she tells him that they both died by drowning.  She explains that their drowning occurred while "on a pleasure trip to Antigua."  Antigua is an island not far from Barbados, where they lived at the time.  Her parents were only married for three years when they died, which indicates that Kit was very young at the time.

Though her parents died by drowning, Kit seems to have no fear of water.  Knowing how to swim was highly unusual for a young woman in Puritan society, yet Kit dives in the water to rescue Prudence's beloved doll in the first chapter of the book.  This shows Kit's independent spirit, but it also shows bravery.  She does not let the fate of her parents dictate her life.