One skein of yarn will make one of these scarves. I've tried worsted, two strands of worsted held together, bulky, and super bulky.
Chain 50 - 60 stitches, depending on the length scarf you want.
Join to first chain to make a circle.
Chain 3. Double crochet in same stitch (this helps eliminate the gap that can form when joining the circle).
Double crochet in each stitch around, always starting with a chain 3 and double crochet in the first stitch. (When joining, make sure you skip the chain 3 and join to ththe first double crochet.)
Work in this manner until the scarf is about 6" or your desired width.
For a double loop scarf, I used one skein of worsted weight and chained 150. I don't have to hook with me, but I think I used a J for worsted weight.
I hope to see posts of other scarves!