One technique that you may want to try is as follows.
On a separate layer, draw out a series of rectangles corresponding to where you want the ribs to be. These will "cut" your hull mesh. Put this layer into the background, and bring your nose mesh into the foreground.
Use the
Solid Drill -> Slice command.
On the foreground layer, select the newly cut polygons, and use the
Smooth Shift command to move these selected polygons inwards or outwards along the polygon normals.
I have found that the Boolean command really likes to work with solid objects/fully enclosed meshes, rather than simple surfaces. The Solid Drill command reallw works well with surfaces, and this technique is especially useful in creating raised hull panels and other nurnies.
I'm not sure how well it will work with Sub-D objects--as with all Sub-D objects, you really have to watch how your mesh is laid out.
