It’s quite late in the piece to be lofting the ballast keel , well in most new carvel builds it is! But I didn’t have the height in my shed to do it that way, instead I built the boat on its plank keel, the plan being to add the almost 2′ (600mm) of deadwood and the lead ballast keel towards the end of the build, which is getting closer. In the video I explain how I lofted, that is, drew up the shape and the sections of the ballast keel which uses identical techniques to lofting a whole boat, starting with drawing an accurate grid and plotting the shapes out in 3 views, plan (from above), the profile view (elevation) and the body plan or sections (end elevation).
I show how I built a plywood and strip-planked plug to send to the foundry so they can cast it in a sand mould, and then we see the lead being delivered, and what a beautiful casting it is! I cast several keels in the 1980s and 90s, and decided I was going to let the professionals do it from then on. https://youtu.be/eB_YAxz0FQs?si=_z87FtMvOyFGvYFJ