If you had asked this question in the grasshopper category of this forum. Looking for a pattern arranged on the surface. You would have this issue solved in a day, tops.
Also, next time provide all the information at the start. Instead of us asking what it is you actually want
Number 5 was trimming faces that crossed over the center line. Your new version doesn’t have any of those, so that leaves number 6 - joining things up.
In order to join objects, there need to be edges that are (1) close enough to each other and (2) that are not already joined to other surfaces. You did not complete Pascal’s Number 2 - extracting ALL back faces of the riblets. There were a few bad objects in those and a bunch of surfaces that were not needed. Get rid of all these, then join, then find internal gaps and fill these.
The attached file has layers that show all these steps - only the layer with the final result is on. Ship with ribblets without gap-wd.3dm (10.2 MB)
HTH,
-wim
Also - Note that your initial hull is self-overlapping and should probably be fixed before you do anything else:
I AM AMAZED AT HOW DETAILED YOUR LAYERS ARE. Thank you so much for spotting my mistakes and making me learn with how clean your set up was. Will definitely try doing this again.
And I am very happy and thankful for this community, you guys are too nice and too smart.