It says a lot about the sophistication of their tools and the term of the ship’s development. It had to be at least two centuries prior to that craft. This one was apparently sewn together with moss as a caulking. Are you familiar with earlier examples of clinker boat construction?
Clinker-built seems to have been popular in northern Europe, I suppose I could look it up though... uh... Wikipedia has the date wrong, by centuries, considering this example. Unless there are alt- versions of sewn boats of course.
Generally, an awl or drill was used to cut matching holes from the inside of the hull to the edge of each plank, then the cord ran through these in succession, with caulk, and wood expansion (and cord contraction) from exposure to seawater, keeping the seam tight.
The Brittanica page uses this boat as its example, which is either awkward for them, or it means there’s been more than one boat found there. The planking on this one (I went to the PLOS-one paper and blew up the graphic a bit) is vertical rather than bow to stern.
https://www.britannica.com/technology/clinker-construction