How can I fix the non-stitched seam that is present after applying mirror modifier? I've followed the same tutorial I mentioned in the question I asked yesterday and my boat hull looks pretty good.  The process is to make 3D B-Splines increase the resolution and then convert them to Mesh Elements.  Then you make a plane and cut it in half along the "Y" axis.  

I followed through the process and see a couple issues that I would like one of you to address.  First, I see that the normals are not correct.  The inside of the hull is not important but the outside needs to show materials.  Also the hull is not stitched together along the keel.  I don't know how to do that on a mesh that has had the Mirror Modifier applied to it.



Anyone care to help?
The normals issue can easily be solved by selecting all the vertices in edit mode and pressing Ctrl+N (You may need to select the Inside option as well, depending on your mesh). You could also add a solidify modifier if you want to have the normals correct on the inside and outside.



The edge loops can be merged together by selecting both edgeloops, and scaling to zero along the Y axis. All you then need to do is to remove doubles.