someone else will have to say where the rebuild command is for MoI v3 and v4. i'm not sure. i know it has one though.

the 90 bends are at the bottom on various profiles. not all of them have them. i would probably add in a radius to them if it where me. unless they are really there. so if you have two different pieces of wood for instance. but in that case i would create the flat sections separately from the curved ones.

you don't have to keep an even number of points. that might be impossible in some cases. but if you can do it, it's worthwhile. with the propellers and fan blades i make, i can keep an even number of points. so the lofts work out good. your ship hull is a lot more complicated. you might have to rely on the rebuild command. the only thing is, it's a curve fit. so you loose a little bit of accuracy. however, the loft is also a curve fit. so you can loose accuracy there too. it really depends on what profiles you are working with. for me, i can get the loft to exactly match the profiles. when i was working with your curves, that didn't seem possible.

you had some tricky areas and it looks like Barry got much better results than i did. i got stuck near the rear. his tips seem like good ones to try.