You may do the navigation of Lake Lago Grey, with the glacier of the same name, from Puerto Natales. In this case, we suggest booking a private full-day tour of Torres del Paine and then adding the navigation of Lake Grey at the end. Available from November to March with 2, with 2 navigations per day.
CLP $ 55.000/person (Nov 1st, 2013 - Mar 31st, 2014)
(*) Price doesn't included transport from Weskar to Torres del Paine.