The Goat Island Skiff kit builds differently than the boats built from just plans.
A Calendar Islands Yawl 16 being built upside down over a building jig which comes precut in the kit. Believe it or not, the CIY was heavily inspired by the GIS and a guy who sailed the heck out of a GIS he built, Christophe atson.
Any modern wooden boat designed these days is drawn in the computer, modeled and rendered in such a way that enables the boats to made into a kit. What does that mean? It could be as simple as using the computer software to generate 2D geometry representing the molds of a boat so that they can be precut on a CNC router. In this case perhaps, the boat builder(s) sets up a strongback the traditional way, spaces out the molds on the "building jig” and planks the boat. Or the designer can go further and model the strongback and building jig itself such that those components of the jig are precut on a CNC machine. The interior of the boat can be patterned on the shop floor and all the transverse structural parts cut by hand from stock, or all that structure can not only be modeled in the computer and precut on the CNC but it is then set up as part of the strongback/building jig so that after planking when the boat is flipped, all the structure is included in the hull. Going further, hardware for the boat can be patterned and fabricated but a serious designer on the computer can model those pieces in their CAD program and export files that allow castings to be 3D printed or pieces of hardware laser cut and welded together.
Mark Nye’s kit components all prepped. Ready to go 3D!
All of this is to say that my goal was to make a GIS kit that took full advantage of the methods available with computer aided design and CNC cutting.
The first GIS kit was a package of precut parts based on the same geometry that a plans builder cuts by hand. The geometry that Mik Storer drew and dimensioned in the plans was available as a file we call a DXF which is essentially the CAD’s world equivalent of a PDF. With those files imported into my software and cleaned up (there is always careful fairing and checking to do when a file is imported from another system), I could then program the parts to be cut on my CNC router. I did that for a couple years. One Goat named GIR is a well known product if this early kit offering.
Besides the time savings to the builder - indeed there was a lot of plywood cutting they did not have to do saving them time and cutting mistakes for sure - there wasn’t anything I can point to that made this first generation GIS kit truly special. During this time period I was experimenting with what I now call the Tab-n-Lock system. With that system proven out on a few other of my skiff kits as well as my NS Scarf, I decided to redesign the GIS kit to create what ships today.
The idea behind the Tab-n-Lock method is to create a way to mechanically interlock the transverse members of the boat - frame and bulkheads - with the side panels themselves. On the frames and bulkheads are precut tabs (about 1 1/4” x 1 1/2” in dimension) that stick into precision cut, matching slots in the side panels. When the side panels are bent around, the slots find their respective tab on each frame and bulkhead and they lock into place securely and without any slop. A small precut wedge holds the side panel in snugly. With this system, there are no bevels used on the frames and bulkheads, saving building time, and they are glued in situ meaning that they do not need to be removed to add glue. Kit builders frame the frame/bulkheads with several pieces of hardwood only on the top and bottom - because the bulkheads are filleted to the hull in lieu of framing and beveling along this joint.
In this photo you can see the tabs sticking through the side panels. These CNC cut features allow the shape to lock together quickly and easily.
For those who build by hand, remember how tricky it was to bring the side panels together and align them to the frames, dry fit them, then remove and glue? This is literally a “snap” with the kit.
The NS Scarf in a set of GIS planks
The other big difference between GIS kit and the normal build method is that there are precut scarfs on the side and bottom panels. This is another proprietary if not trademark of CSC kits, a feature we call the NC Scarf. It is an interlocking joint like you see in many other kits out there - the interlocking joint is crucial to the ability of the precut plank to align perfectly such that we get what traditionally we call the “sweep and spile” of the plank. But I never liked those ugly joints and I did not want my boats to come across as a :kit boat”. So, the interlocking geometry is hidden on the inside of the overlapping joint and all you see on the outside is a slight wavy pattern, which helps increase joint strength.
There are a few other bells and whistles included in the plywood kit. But we haven’t even mentioned the other aspects of the GIS kit: the solid wood is precut to dimension with scarfs for the builder to glue them to length (only hand tools are needed to build the kit); all the hardware has been figured out and included for the builder; the epoxy kit provides exactly what is needed for gluing, filleting, laminating and glasswork. There are resources I include in the manual and plans that only CSC customers have, such as plans for making the YAWL version as well as how-to instructions and I hope soon some videos.
I would be remiss not to mention a few other cool things we do for the GIS kit: we can precision mill the foils on our CNC router. The shape generated is more precise than even the most skilled hands can generate but if people want to make their own foils we have foil templates that we include. There are the parts and instructions for people who wish to make a yawl version. There are sawhorse cradles to build the boat on, oarmaking kits fit to the GIS, kits for making a birdsmouth mast. And best of all, builders can call me with questions.
Just as the name of this BLOG suggestions, nothing is perfect and we are always striving to improve all or kits. My only regret with the GIS is that I did not 3D model the boat, so there are some limits to what I can do. But it has become a heck of a kit offering that we are proud to ship and - like MIK does with his resources online - make this incredible design even easier and more accessible to build for people in the US and Canada. But people should remember this: you are building a boat. This is not a shelf from IKEA or a birdhouse from Boy Scout days. Even with the best kit ever, it is still a human-built, real wooden boat made from bent wood and shaped by hand with real tools. Now, I should go - I have a 12 year old GIS that finally needs a little TLC and the snow is melting!
Greg Underhill’s GIS was launched last year. A brand-new boat builder with a growing career and young kids, he did a great job!
Kudoes to Mark Nye for helping me document an early 2nd generation kit for the Goat Island Skiff. Great color!