Before planking the hull i had to trim the stringers into shape. This step must be done very precisely to avoid any bumps in the planking that gives you significant amount of work when filling. I started to trim the stringers with the electric planer. The finishing was done with the hand plane. Finally, I used my sanding board to shape the stringers. I use a measuring stick to check whether the smoothing is sufficient.
Handplaner with guide rail
Sanding board
Measuring stick
Stringers shaped and ready for planking
Be careful with the 30mm stringer at the flat hull side (not the 30mm chine stringer) between frame B and frame C. Due to the bend, it can protrude slightly outwards. If you now try to trim back these protruding part of the 30mm stringer, they will be thinned out and therefore bend even further outwards.
The hull is covered with 10 mm Okoume plywood. The bottom is planked with 20mm (2x 10 mm).
I have done the planking in 4 steps:
- First bottom planking
- Side panel planking
- Chine panel planking
- Second bottom planking
This order may only be possible if you build by plan. The CNC kit planks are short cut and therefore a different order of planking must be chosen (1. side planking, 2. chine planking, 3. 2x bottom planking).
I cut the planking to size by placing the large 1.22 x 2.50 m panels on the hull, marking and cutting them out. I left about 2 cm overhang on each side. I dryfitted the planks and fixed them with clamps on the stringers. I climbed under the hull and marked the position of the frames and stringers from the inside. Then i took of the planks again and drilled the holes for the screws.
Step 1: The acces to the bottom of the hull was easy by climbing onto the stringers. I glued the planks with thickened epoxy (epoxy + cotton fibers) and fixed them with stainless steel screws. In the area where the planking rests on the frames I used 5×40 screws. To fix the planks to the stringers 5×25 screws was the maximun and I had to be careful that the screws didn’t come out on the underside of the stringers. Choosing the screw position is not easy because you cannot place the screw heads too close to the edges. These screws could bother you when sanding and rounding the edges later. As a solo builder, I used a support to help me hold the plate when gluing the bottom plank.
Step 2: Side panel planking was a straight forward job. Before planking I cut off the butt blocks that will be placed on the inside of the joints.
Butt blocks astern (upper section is extended for reinforcement of the series drogue chainplate attachments).
Butt blocks in the cabin (plus extra 10mm plywood reinforcement for the shroud chainplates as per plan).
I used little helpers that I attached to the 70mm stringer to hold the plate when gluing. Again i fixed the planks with 5×40 stainless steel screws whre the planks meets the frames and 5×30 screws to fix them on the stringers.
Immediately afterwards I attached the butt blocks to the inside of the hull at the joints of the planking. With screws (3×16) and clamps i was able to press the butt blocks to the joints.
Butt blocks in the cabin fixed with clamps while gluing.
Gluing the side panel planks.
Then i had to trim the overlapping 2 cm of the bottom and side planks in the chines section and had to sand the stringers again.
Step 3: Fixing the chine planks where they meet the straight sections in the back of the hull was as easy as the bottom and side panel planking. The front chine planks in the bow section gave me some problems. With a lot of strength, straps and clamps, I managed to bend the 10mm Okoume plywood panels into shape.
Step 4: Finally, I glued the second bottom planks with a layer of thickened epoxy and fixed them with stainless steel screws (5x40mm screws to the frames through the first bottom planks and 3x16mm screws to the first bottom planking). I had to make sure the epoxy wasn’t thick. I started screwing in the middle of the boat and standing on the plank with my weight to let the epoxy flow out to the sides.
Finally, I sanded the planks where they are screwed onto the stringers and rounded the edges of the planking to easily apply the hull glass around the corners. This lowers also the risk of damaging the fiberglass when sanding the hull.
Next comes the lamination of the hull.