To cut the joints for the chine logs I used a router. It gives you a very fine edge with low error. I chiselled the first three floors, but routing is better. Here you can see the setup. The floor is fixed to my “work desk” with a clamp. The guide rail is a simple wood scrap piece fixed to the desk with some clamps in an improvised fashion. Without the guide rail the router would perform havoc on the timber.