In Praise of Lofting

Over the last twenty years I've taught various sorts of boat building workshops at crafts schools and museums, and one workshop that has never failed to attract attention is lofting. I begin each class by asking students if they have read any books or articles on lofting. All hands go up. Then I ask if they have been able to loft a boat and all hands come down. "Learning by doing" probably applies better to lofting than just about any other facet of traditional boat building. The misconceptions are dramatic (most of my students believe lofting requires advanced mathematics) but the advantages are tremendous. At its most basic, lofting allows the builder to get precise patterns for moulds and bevels, and most boat builders, even professionals, only go this far.

The screen can't do justice to these large drawings - this is a greatly scaled down sample. For better examples visit the lofting page on Douglas' site. Ed

I'd been building boats for a few years before I was introduced to Sam Rabl's obscure book Ship and Aircraft Fairing and Development. This volume is a fascinating lesson in the possibilities of lofting principles, and from it I learned how to derive the exact shape of the stem rabbet on the lofting floor. Up to that point I had been still making my stem rabbets with the old "cut and fit" method. The ability to lay out the entire rabbet and cut it on the bench is an enormous time saver, as are the myriad other details and patterns that can be derived from the lofting. Howard Chapelle's comment about lofting is still correct, "There was never a boat built in which too much lofting had been done."

The last few years has seen an explosion in plans for small boats made available with full-size paper patterns. Clearly designers have recognized the need to provide amateurs with parts of a lofting, but in one sense I find this trend regrettable. First I am often not a fan of modern attempts at traditional designs. I find that many of them lack the subtleties of shape and line that give traditional designs their inherent character. I am afraid that amateur boat builders feel that they have no other choice but to choose among these options when there are hundreds more traditional designs available to them at very little cost. The Smithsonian Institution, for instance, has all the drawings of Howard Chapelle and Harry Sucher available in plan form. Mystic Seaport has plans of dozens of its small craft collection available, as do many other maritime museums. Plans are also available from other researchers and architects – Bob Baker and William Atkin come to mind. Lines drawings and offsets are published in numerous books and magazines (with a good magnifying glass you can pick Chapelle's offsets from his books). With just a published set of lines one can scale the offsets, which will be corrected on the lofting.

The obstacle, as my students demonstrate, has been the ability to loft. A few years ago an amateur boat builder hired me to take the lines (measure) and loft a boat from a local museum collection so he could build it. The boat had badly lost its shape but in lofting it I was able to derive its original shape. The job got me thinking that perhaps there might be other amateur boat builders who wanted to build a particular boat but needed it lofted. So I added a lofting page to my website: (www.douglasbrooksboatbuilding.com).

At the moment I am lofting an Atkin design for a client in Florida. Years ago when I was building boats for a museum I found storing loftings on sheets of plywood cumbersome, and so I began lofting boats on rolls of high quality paper. Now I can loft a boat in 3'-4' wide paper, roll it up and mail it to a client. I also take a sheet of mylar and loft the bow and stern, along with the body sections. The mylar is a more permanent record than the paper and because it is clear it is easy to lay over the mould stock to transfer shapes. The prices I charge for this service are comparable to a package of plans and patterns from other sources. The ability to build exactly the boat you want? Priceless.