Hi Jo, 
Welcome to planDisney and thank you for asking us a question!
I’m really hoping to experience a 
Northern European voyage aboard 
Disney Cruise Line some day soon and visiting Norway is definitely on my Bucket List. 
From what I understand, there’s no Pirate Night on these itineraries, as well as Alaskan voyages because, instead, Guests on those cruises get to enjoy the 
Frozen Deck Party! These parties, which are available on 7-night sailings, totally transform the Disney Dream for a day in order to transport cruisers to Arendelle, which will be absolutely perfect during an itinerary through the Norwegian Fjords. From what I understand, these parties typically take place on the 5th night of a 7-night sailing, but that’s subject to change for your sailing. 
I hope my answer helps you plan the perfect vacation this September. Please don’t hesitate to come back and see us if you have any other questions!
Have a Magical Day, 
Lynne