Yeah, I watched the whole fascinating video and wondered the same thing. Suddenly the halves had been parted and reassembled. How to do that without inducing a twist or misalignment? This person is obviously such a master builder that maybe he doesn't have such problems.
Presuming these kayaks are made for sale, imagine what they must cost! A $100,000 kayak, anyone? And, as a sea kayaker myself, this boat is for experts only. No visible chines and very rounded hull. Incredible project!