The company that owns these boats called bbtouring. (
http://www.bbtouring.no) They are serious players, so it's hard to be certain on what caused the accident. Police are investigating the cause. However these accident are usually due to human error...
11 people are in hospital. 2 of them have serious injuries, but are stable. The remaining 9 have minor injuries.
Here is a video of the crash site immediately after the accident:
https://www.nrk.no/troms/se-video_-h...nen-1.13382298