In the last post we prepared the bottom board to receive the ribs and stems. The board was beveled so that there would be a smooth transition when going from the bottom board to each of the ribs. Holes were drilled in the board for the screws that would fasten the ribs to the board.
In order to more easily fasten the ribs to the board, it is hung horizontally from the builder’s jig with its bottom side facing inward. This makes positioning each rib easier so it matches the bevel of the bottom board as closely as possible. There should be a minimum gap between the rib knuckle and the edge of the bottom board.
Before cutting out the bottom board I had laid out each rib station and lined it off. Now I use those lines to set each rib in place. I clamp a piece of approx. 1″ X 1″ stock to the bottom board right along the station line. Then I clamp the rib for that station to the stock. I carefully set the rib so that the gap between the rib and bottom board edge is minimal. Here is what it looks like:
Here I am checking to see that the rib is coincident with the bottom board edge.
Once you get all the ribs on one side of the bottom board it looks like this:
The board is then flipped over so that the remainder of the ribs can be put on.
Fastening the remainder of the ribs goes more easily. You just clamp the unfastened rib to the one already fastened, drill tapered holes in the rib, and screw them on.
Now the bottom board with its attendant ribs get hoisted up on the builder’s jig beam and secured. It looks something like a beached whale carcass. Now the stems are attached. Here I am drilling the tapered holes for the three #12 by 1 1/2″ screws that hold each stem to the bottom board.
The stems are supported at the end opposite the bottom board by a cantilever arrangement.
Next splines, or thin battens, are attached to each rib along the shear line. These keep the ribs in position during planking.
Spline being attached to the ribs.
Once the spline is attached, the delicate arrangement of ribs and stems is braced. This holds everything in place during planking.
I must attend to the stems to ensure that they mate nicely with the bottom board. I start with a chisel.
The final shaping is done with my sanding long board.
Carl Hathaway, who taught a course in guideboat building in Saranac Lake, stressed the importance of maintaining the stems and bottom board “absolutely plumb and level”. He narrates the video of Willard Hanmer building a guideboat. This video is shown in the watercraft building at the Adirondack Museum. While in the Museum’s boat shop answering visitors questions while Allison builds guideboats I must have heard Carl exclaim in a loud voice “absolutely plumb and level” hundreds of times. So if I get nothing else right I better make sure my stems and bottom board are “absolutely plumb and level”.
Here is the bottom board being checked to see that it is level.
Now we check to see that the stems are plumb, or perpendicular to the bottom board.
So we are now ready to start planking. Next time we will take a break from building to have a look at Brian’s boat.