Missing at Sea — Rita Lee Chapman

Three years on from Egypt, Anna Davies embarks on her first cruise with best friend Sandra. A few days into the holiday they are woken by three blasts from the ship's foghorn, indicating that someone has fallen overboard. A woman is lost at sea; the ship turns around to search for her, but she has disappeared into the night. Was it suicide? Did she lose her balance and fall - or was there foul play involved? Did her husband push her? Would anyone be able to prove whether this was murder or an unfortunate accident? What a perfect place to stage a murder!