Step 1: Gather
Go to the beach and find your perfect driftwood stump. I found a palm trunk that was easier to carve than a hardwood would be. Bring a chainsaw or a couple of hardy friends, whichever is more readily available. :)
Step 2: Shape & Coil
Using a handsaw, cut a half-inch deep line at the height where you would like the rope coils to start. Try to make this cut evenly deep all around - this will be your guide for the rest of the shaping. The top of the seat is carved by removing the unwanted material with a wood chisel bit by bit. It is much like sculpting but it doesn't have to be perfect, as you will have the rope to cover up all imperfections. My first seat of this kind was almost entirely shaped by the ocean, so I didn't have to carve too much. :)
Don't forget to also carve the two notches on either side of the stump, below the rope line. These will become the indispensable gripping handles once the rope is wound up (detail in drawing #4).
Adding a circular piece of softer padding at the very top of the seat will greatly improve comfort. I prefer to use coir or coconut fiber.
For this project, I used an old climbing rope that I had lying
around. I've previously also used an inexpensive manila rope, which is good for outdoor use. If you have a rock climbing gym nearby, you can ask them for their retired ropes, as they have to change out their ropes routinely for safety reasons.
Drill a hole (same diameter as your rope & ~ 1.5” deep) into the stump, anywhere on the starting line. Insert one end of the rope into this hole. Dipping the end of the rope into some 5 minutes epoxy just prior to this will help it to stay in.
Now start coiling the rope. After the second loop, you can start stitching each new (top) loop to the one below. Keep going in this manner with the remainder of the rope, keeping the coils tight & your stitches even as you go. Once you go over the ridge (top curve) of the seat and your coils start becoming smaller, you will have to push/adjust them out into the preceding coils in order to make it a tight-fit.
Once you reach the center and can make no more loops, cut the rope with an extra inch and push this tail in, making sure everything sits flat.
Step 3: Enjoy
Enjoy your Briccorda seat & make some more to accompany it. Buy some beer for the friends who helped you at the beach. :)