It was a pretty easy project too, and fairly inexpensive.
We already had the 2x8" board. It was left here by the previous owner along with some other miscellaneous lumber that we've put to good use around here.
A synthetic rope will last longer in the elements, but I like the look of the natural fiber.
Our big Sugar Maple provided a perfect limb, right outside the farmhouse covered porch.
We measured from the limb down to an approximate seated level.
Which was 12 feet,
times 2 for each side of the swing = 24 feet
We added 10 more feet to go around the branch and for knots, which gave us five extra feet per side.
Handy Man How To. This type of knot will expand as the tree grows so it won't damage the limb.
We mad a knot in one end of the rope, swung it around the tree limb and snaked the long end of the rope through the loop.
It took a couple times untying the knots to get the swing board level, but in the end it made a perfect swing!