How to lash a ring to a spar

[benz]

It will hold, as long as the knots are tight enough to not shake out. I like thinner line because the frapping would lie more tidy, and nylon is nice because if pulled pretty tight the stretch will help hold the knots in. If using Spectra or Dyneema lashing, you'd want an even thinner diameter than nylon, and to back up the knots, as it's slippery enough stuff to easily shake them out. Ashley will be a very good resource for lashings.