Hi Gord, so I was thinking of how to explain this... One of the reasons why you're having problems with the ship hull is that you're sticking too much to the "solids and booleans" type modeling method when working on the hull.

When you're working on something like that it's better to work for a while in something like a "skinning" type mode where you want to focus on getting surfaces that touch each other accurately at their end edges. The way to ensure that is to either have 2 adjacent surfaces either constructed from common curves or have them extend through each other and cut each other with the Trim command, then the intersection will be accurate enough to join.

When you're in "skinning mode" you don't want to use booleans. Booleans are good when you're working with solids. But one of the things about booleans is that they are expecting objects to cut each other and for some material to be removed. If the pieces have freeform surfaces that come close to meeting but don't quite align precisely enough then you can end up with little slivery pieces being generated from the intersection. That's what I was trying to show in this previous message: http://moi3d.com/forum/index.php?webtag=MOI&msg=9819.90

So to avoid that when you're in "skinning mode" you don't want to use booleans, you instead use Edit > Join to glue surfaces together. Unlike the booleans the Join command does not try to do any surface/surface intersections and does not try to remove any material, it's only job is to glue edges together to make a larger skin. When you have formed all the pieces and glued all edges up then you'll have a solid and you can then switch back to boolean operations then.

Basically you want to be using a different area of the toolset when you're working on the hull, using the surface modeling tools Trim, Join and Blend and not booleans right then. It's a more advanced aspect of NURBS modeling and has a longer learning curve. Also models that are going to need a lot of this type of work can potentially be easier to do with subdivision surfaces rather than with NURBS.

- Michael