The report from the investigation is out now and blames the Captain and his lack of experience in Antarctica.
The ship operator doesn't come off too well in terms of procedures for evacuation and quality of emergency equipment available.
"Investigators said the open lifeboats were so crowded people had to stand, and one of the most damning revelations was that three of the four engines on the lifeboats did not work."
From this summary: http://blogs.mirror.co.uk/captain-gr...plorer-si.html
Also see The Independent: http://www.independent.co.uk/travel/...r-1667532.html
Full report here: http://www.photobits.com/dl/Explorer...l%20Report.PDF