i want to put up a 3 post triangular arbor and sling a hammock between the
outer posts. i'm looking for a 2 person hammock, so the posts should be able
to support up to about 350 pounds. how deep should i sink the posts? i'll be
using 2X8 pressure treated wood to form the triangle at the top of the
arbor, so there will be additional support where the two outer posts would
want to sag in to the middle.