One of my high school class’ CAD drawing of a Vermont trapping boat. A very simple hull form, but this has all the elements of a comprehensive boat drawing: a table of offsets with all the dimensions needed to replicate the drawing full-size, and a scantlings table listing the boat parts, species and dimensions.
I have been teaching lofting workshops for over twenty years. Typically these are two or three-day workshops where I first have students loft a very simple, straightforward flat-bottom skiff, and then get into lofting a more complex hull. Most of my students have a particular boat in mind they want to build, but lofting it is there first obstacle. Others are just interested in what can seem like the dark art of traditional boatbuilding. As more and more plans kits come on the market, all heavily advertising the fact that no lofting is required, what is forgotten are the hundreds of traditional boat plans easily available from museum collections and books that can be successfully built once lofted.
I introduce my workshops by showing students a historic lines drawing I found in a book. There was no table of offsets (the dimensions that are the normal starting point for lofting) but I enlarged the drawing on a copy machine until I had a version that was one inch to the foot scale. Then I scaled off the offsets, lofted the lines and built the boat (see: http://www.douglasbrooksboatbuilding.com/rushton_cat.html). In my workshops I try to delve as deeply into the subject as possible. This includes lofting the stem rabbet, a huge time-saver when building the boat. I also show students how the lofting provides patterns for many of the construction details.
I’ve taught lofting workshops as long as five days, and these give students the chance to loft several boats and I can introduce half-model making. Half models are the precursor to lofting. In addition to being a fun, rewarding hand tool project, making one helps cement the principles of lofting for students. In my work studying the boatbuilding traditions of the Lake Champlain Basin I regularly have my student researchers measure historic boats and loft them, all in preparation for creating CAD drawings.
Want to build a boat but don’t want to have to learn lofting? See my LOFTING page for more information about my services lofting boats full-size on large format paper for amateur boatbuilders: http://www.douglasbrooksboatbuilding.com/lines.html