Over the last week and a half the crew has been working long hours to finish planking the boat. Saturday afternoon we nailed up the king plank, and the boat looks fantastic. With the skin on the boat, we have passed a huge milestone in construction. We only need to pack the seams with oakum before she can be flipped and finished. In planking the boat we used all green lumber below the water line. Typically, batteau builders have allowed their boards to dry out, and kept track of how much width the boards lose. Boats are then built with flush seams, and ripped with a circular saw to allow for packing oakum and swell once the boat is put back in the water. Instead of calculating the swell of the boards, we built a trough from cinder blocks and tarps, and kept all of our boards soaking. Doing this allowed us to build the boat flush, then let the boards dry out and gap so we can pack oakum (wood fiber and grease) into the seams. Once put back in the water the boards will swell to their original width, ensuring extremely tight seams.
Each run of planking requires several specific steps. First, we need to figure out the width of board to use, and where to place butt joints. Butt joints need to be alternated along each run of planking so as to avoid a hinge effect at pinch points on the boat. Essentially, we don’t want successive runs of planking with joints on the same rib. With the width determined, each rib must be planed to fit the board so we have a flat surface to fasten it to. Planes must be planned and made 2 runs ahead of the last run of planking nailed up in order to have enough room to operate the planer effectively.
With the planes made and boards selected, the board must be ripped on an angle so the seams will be flush from inside to outside. The best way to determine the appropriate angle is to clamp a board into the position of the next run of planking, rest the fence of the circular saw on the run below it, and, with the blade at 90 degrees, rip the seam so the blade cuts just below the outside corner of the top board. Once the angle was determined, we set the circular saw to the proper angle and ripped the board. Once the board is cut we generally planed the inside edge to eliminate any error in the saw cut.
With the angle cut, we then cut the butt joints. We used three boards for each run of planking and were careful to avoid placing butt joints on the same rib. Butt joints are cut so that the planks evenly split the width of the rib at the joint. Once we liked the way a board fit, we clamped it into position. Each board has a natural bow and cup. At times it was a laborious process to force the board to go with the taper and rocker of the boat, but we developed an effective system of getting boards into place and are very pleased with the final product.
With the board in position we do our standard pre-drills for our boat nails. While one man drives the nail into position, another sits on the inside of the boat and braces the rib arm to avoid any splitting. The first three runs of planking were made with the top 2 runs at 6” wide and the third at 10”. By placing a 10” board on the water line we hope to avoid having a seam that sits directly on the water line. After the first three runs, things became a bit more complicated. As the boat is tapered, once we began working our way into the flatter sections of rib, we needed to begin tapering our boards. Knowing that our king plank would be 9” where it met the nosecones, we decided to keep it 14” on the center rib. We then split the difference between the remaining distance between our king plank marks and the last run of square planking three ways. With our lines marked on each rib, we would clamp a board into position aligned with the appropriate lines, get under the boat and trace out where we needed to cut. On each run of planking that was tapered there were 2 transitions, with the angle becoming more gradual with each successive run.
With the line drawn, we ripped the board and followed our standard angle cutting and planing procedures. The most difficult part of cutting the tapered boards was creating a smooth transition were the angle of the prior run changed with the taper at the butt joint. Once we were into the tapered boards, we also had to change our clamping methods. We used ratchet straps to bring boards into position as we did not have any clamps that were long enough.
Once we were planked up to the king plank we took a trip to go retrieve the board from the pond it has been soaking in. The 44′x16”x1” oak board easily weighed several hundred pounds. After cutting it down to a more manageable 36′ (we only needed 33′), we placed it over the gap in the boat. From underneath the boat we traced out the lines we needed to cut and flipped it over.
Once the board was cut we planed the edges just enough to allow the board to be stomped into its space. The king plank spans the entire boat, reaching into both the nosecones.
We believe the one piece king plank, along with our continuous cap rails, will lend significant structural stability to the boat. Finishing planking was a huge step for the crew, and the boat looks awesome. There is very little flat on the boat, with 2 distinct chines below the waterline. In many ways it resembles the hull of my creek boat. With proper weight distribution, we will be able to dig an edge of the boat into the water as we make moves. When running rapids in a kayak, you edge into deeper water to effect a turn. I expect to see the same principle at work as we run rapids on the New.