Unlike other ships in the Great Lakes, like Viking's expedition vessels that also sail in Antarctica, the Navigator and Voyager were not designed to sail in other climates.
Zell amassed a net worth of $5.9 billion through real estate and investments including radio stations, drug stores, parking lots, mattresses and Schwinn bicycles.
Sam Zell was a billionaire investor dubbed "the grave dancer" for his bets on distressed assets, including a losing wager that drove the Tribune into bankruptcy.
Sam Zell, billionaire real estate investor, dies at 81 courant.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from courant.com Daily Mail and Mail on Sunday newspapers.