I would avoid any streaming app. The bandwidth on most ships is tight, remember you are going through a satellite, and per minute charges could be really expensive.
All I ask is a tall ship and a star to steer her by; John Masefield
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012, Dream 2013
Celebrity: Summit 2011
Princess: Ruby 2010, 2014, Caribbean 2013, Coral 2014, Regal 2014
Star Clippers: Royal Clipper 2015
I know this post is old but I stream music through rhapsody subscription. I make sure to download a bunch of music to my phone and then can listen during the whole cruise. If you download them you can do it with your subscription and then listen while your phone is in airplane mode. Rhapsody is also available on your ipad.
We love to travel! Disney, Vegas, Cruises, you name it.