i looked at the geometry some more. unfortunately, there are a lot of things that would need to change. one thing to consider is all the sharp corners in your profiles. that's not a realistic surface. meaning, it can't be built like that. so you would want to put in the radius values of the real thing. i went to start rebuilding and joining the curves, but there is just a lot not quite right. you have the general idea though. i think the loft isn't working out in rhino due to all the pieces of each profile. so they at least need a rebuild. but that becomes problematic given the structure. this should be doable though. just needs to be redone with different curves. once you get the hull surface. you can do an offset if you want it to have thickness. the part running down the middle you can do with one curve. it doesn't need to follow the hull shape. it can go straight through the hull end to end. then you would union, join, boolean depending what you have.