Glueing pieces of the foam together:

Typically the foam comes in sheets, ranging in thickness. Depending on the size of the model you're making, you'll probably need to glue some together to get the full size of the hulls you're making.

But, there's another aspect of doing this from the sources I've seen. Basically, you get the stations like Erez did. Then you glue pieces of the foam together with the wood stations in the proper locations, then fair the foam down to the wood stations. This give you a fairly easy way to get fair lines with out having to constantly be checking with a template.

You could also do it length wise - cut your wood to the full profile shape, and glue the foam on either side of it. You could also use the longitudinal lines from the hull profile (if you have those) in a method similar to above - in this case you'd have wood down the middle, a piece of foam on either side, wood on both sides corresponding to the lines, then foam on the outside.

You could also just glue the pieces of foam together length-wise, cut to the lines, then fair down.

In the end you might want to use varying thicknesses to get the stations in the right place.

Again, once you cover the hull whichever way, if you like the shape it can become either a male mold or a plug to build a female mold.

Another interesting technique would be to use the hull you've made as a male mold, and draw a heated sheet of plastic over it - it will conform to the hull shape, and when it cools you have a molded plastic hull. This technique is also used in modeling to make a variety of parts, big and small. If you come up with something good, do this and sell a bunch of them....