oh,,just to beat this dead horse more the biggest reason to not building the NBxl is that it was a totally made up design based on no prototype or paddling to determine the integrity of the design before marketing it. In production for over a year and there was no in house demo version.
The NBxl should be simply a higher volume version of the NB...it's not. There's more windage in the stern on balance than the NB. The v of the bow is tighter than the stern compared to the standard NB . The pivot point is forward compared to the standard NB. Combine all those attributes and you couldn't ask for a better way to make a kayak weathercock excessively. Just the comparison of the two kayaks would make one ask " but why MAKE it easier to weathercock?"....because no one made it to determine whether what happened on the drawing table worked on the water.
The assumption that a design doesn't require testing could be reasonable or hubris depending upon the circumstances,,,but for the folks who can build only a few kayaks due to developing epoxy sensitivities it's a waste.