The ship was designed as a seaside resort excursion vessel (i.e.
Seebäderschiff),
but mainly to provide the ferry service between mainland Germany and the Isle of Helgoland in the North Sea off the German North Sea Coast.
The design of the new HELGOLAND is kind of a homage to her extremly popular forerunner on the Cuxhaven-Helgoland haul, the 70s build
FUNNY GIRLwhich, due to her elegant lines with the distinct sheer-shaped knuckle line, also has many fans among German ship modelers.
A sister ship of this Mützelfeld-Yard design is still running in the Adler Ships Fleet whose GA plan can be downloaded from their website
here.
On the new HELGOLAND builders' website you can, if you follow the link at the bottom
from this page, download a PDF leaflet with the specs.
Also on the Fassmer Yard website I found
this leaflet about the dual LNG fuel system which the new HELGOAND is equipped with.
On one 3D cutaway schematic diagram the unusually long mast is labelled as
LNG vent mast.
I try to attach the profile and this 3D view, captured from this latter leaflet, to this post.
P.S. You can watch some onboard pics and a video of the new HELGOLAND on her owner's website
here.
Interesting photos from her hull's assembly on a sub-contractor Szczecin shipyard can be viewed
in this brochure.
Probably easier to read for you,
here is an English ship description.