is there high movement and motion in alaska on the cruise ships?
shall i take lots of travelling tablets?(im on the lowest deck)

What ship are you planning on taking? Except for the Wind, all NCL ships sail at least north or southbound in the Pacific Ocean west of Vancouver Island, some in both directions.
While sailing in the Pacivic Ocean, the seas can get rough. If you get seasick easily, carry your motion sickness medications.