rope thickness

[Bunnybrains]

hey I found 2 types of rope in my garage (I have no money) I attempted and almost succeeded with the first (probably about 8/12 mm) but it was so coarse the knots didn't hold right. another type is about 16 mm, it's less coarse and looks like it might be more successful. idk. just looking for advice since I can't buy rope rn

 

[Eriktf]

try both then use the one that seams to be the best