Ahoy there Anthony,
The
Pirates and Pals Fireworks Voyage is one of my favorite ways to see the fireworks at Magic Kingdom! Its super fun for the whole family!
Typically, you are on the boat somewhere between 55 - 60 minutes. However, this can vary a little based on all of the variables they may have to contend with during the voyage. On nights when there are special fireworks presentations at Magic Kingdom, you could be out on the water for a little longer. Be sure to ask when you're making your reservation.
The cruise was super smooth each time I've been on it. The water is usually pretty calm because the areas you are in on Bay Lake and the Seven Seas Lagoon do not have heavy boat traffic. If a member of your party is super sensitive to motion sickness, you may want to consider that when booking. I know there are always exceptions to the norm but I haven't seen anyone have any problems on any of my voyages.
There are restrooms located in the Contemporary Resort for the "land" portion of the experience. Patch the Pirate will also give you one last chance along your walk to the dock for your voyage. However, there are no restrooms on the boats and there is no chance for a "potty break" while you're out on the water so plan accordingly.
The time passes really fast while you're out on the water because Patch keeps everyone thoroughly entertained. I recently answered a question with some other details of the voyage - click
here.
I think your family will really enjoy this experience. Wishing you many magical memories :-) Allison