STITCHING & RAISING BOTTOM PANELS
February 14, 2021
Putting the Stitch in Stitch-and-Glue
With our hull panels complete we can now introduce the stitching component of stitch-and-glue boat building.
The stitches on our boat are literally just that: lengths of steel wire used to temporarily hold the seams of the hull panels together and in place on the bulkheads. The stitches remain in place until the components are joined with tabs (small 3" by 1" pieces) of fiberglass set in epoxy. Once the hull panels are tabbed together – locking them in their final position – the stitches are removed and the seams are reinforced by a strong laminate of biaxial fiberglass cloth set in epoxy – putting the glue in stitch-and-glue.
Thicker gauged wire was used to hold the panels together at the bow and stern where resistance to bending was greatest. A pair of end-cutting nipper pliers were the best tool for twisting the wires to the desired tension.
The panels that make up the bottom of the hull are the first to be stitched together. To start, we positioned the two panels so one was on top of the other, inside face to inside face, and drilled holes along the length of what will be the keel edge (very bottom seam) of the hull. Six-inch segments of steel wire (the stitches) were threaded through the holes and twisted with enough tension so that they hold the panels in place along their chamfered edges when they are opened up and placed on the bulkheads. The holes are spaced six inches apart along the length of the panels except for at the bow and stern where they increase in density to one every two inches. This is because the shape of the boat is more complex at the bow and the stern, especially the compound curves of the bottom panels near the bow. These sharp curves require more stitches to hold them in place for two reasons: to get the necessary torque to pull the panels together; and to help keep a fair, smooth curve along those edges with the most resistance to bending.
Twisting the 14 gauge (thicker) stitches to their desired tension at the bow end of the panels.
When drilling holes for the wire stitches we used pieces of scrap plywood held on either side of the panel to prevent damaging the face of the panel with the drill, and to limit blowout on the opposing side.
Raising the Bottom Panels
In undertaking this large-scale project, we are often confronted with logistical issues pertaining to moving big, awkward pieces around the shop, and finding places to store those pieces until they become part of the boat. We designed our shop with the initial intention of building one of Sam's smaller boats, though it was modified to fit the larger Camarone design when we decided to go that route with Burnett. But, it seemed that each iteration of the design that Sam sent us had Burnett’s overall length slightly increasing. We couldn’t be more pleased with the final design, but now we are building a larger boat in a shop that we knew would be a bit cramped, even for a smaller boat. This requires us to get creative with storage and use-of-space.
Eric and I moving one of our smallest scarfed panels. You can see some of our finished panels (right) screwed into the shop posts to keep them out of the way.
We are building the hull of Burnett upside down. First, we will be attaching our bulkheads to a rigid building frame that will act as a backbone holding everything plumb (vertical) and in the correct location until the stitches are out and the fiberglass has locked everything in place. The bottom hull panels, once stitched together, are the first panels to be positioned by spreading the matching pair like opening a book and draping them over the bulkheads. For a smaller boat this pair of panels can be easily carried by two people and set on the bulkheads. Our bottom panels weigh around 400 pounds and are just shy of 37 feet long, so carrying the panels and placing them on the bulkheads (many of which are more than 8 feet tall!) is impossible for the two of us to do alone.
With the bottom panels finished and stitched together, where to store them and how to get them onto the bulkheads when the time came was next on our minds. In non-COVID times we would coerce a group of friends with cold beer to help lift the panels and put them into place, but without that option we had to use a different strategy. We determined that using a block and tackle pulley system to raise the panels up to the shop’s tie beams would be our best bet. Up there, they would be in position to be lowered onto the bulkheads and would be stored out of the way in the meantime, freeing up work space.
The beefy tie beams of the timber frame have proven to be very helpful in storing materials and hoisting heavy objects.
The system worked well, and we successfully raised the panels with the help of Eric’s parents on the ropes. It was a punctuating moment in the build as we moved from working in two dimensions to three, with Burnett showing the soft curves of her hull for the first time. It was a great feeling seeing our seemingly abstract plywood panels bend into shape and finally resemble something boat-like with appealing lines. Having reached another milestone in the project, the warm, empty waves of the South Pacific were feeling that much closer.
With our hull panels cut out and stored out of the way, we were ready to get our building frame in position on the floor and set up Burnett's bulkheads!