I would contact your cruise line to be sure, but I don't think that you do. I know you need a form if you are divorced and sharing custody or if you are traveling with a child not directly related to you, but I think you're fine otherwise. I would still check though.
Have a great cruise!
Not All Who Wander Are Lost
Your daughter is almost a legal adult, there should be no problems with Canadian Customs in Vancouver. If she is travelling on her own passport, then no worries. A copy of the divorce papers/custody agreement would come in handy if they do question.
2007 Victory & Triumph
2008 Conquest & Liberty
2009 Valor, Freedom, and Splendor
2010 Glory and Liberty
We have traveled twice with grandchildren. The first time, we downloaded the Carnival form letter and had both parents give notarized signatures on the forms that we could take them with us. No one even asked to see them.
Last month, my daughter traveled with us and she had her children. She has joint custody and had the father sign (notarized) letters for each of the children allowing her to take them on the cruise. At the check in desk, every single letter was scrutinized by the clerk.
I would say "better safe than sorry" and have the proper docs with me when I checked in.
Been there - done that:
2005 Holiday, Sensation, Conquest,
2006 Conquest, Celebration, Holiday,
2007 Freedom Grand Med, Holiday
2008 Fantasy & Sensation,
2009 Fantasy, Holiday & Dream Grand Med
2010 Fantasy and B2B Elation
2011 Monarch of the Seas
2012 Booked - Breeze from Barcelona 12 days