- Pick a sturdy deciduous tree to hang your swing from. The whole tree, not just one branch, should lean out over the water.
- If your swing will be permanent, use weatherproof tenex rope ($30). Static rock-climbing rope is OK if it’ll be up for only a day or so.
- Rather than tying the rope to the branch, loop a webbing sling over it and tie the rope to a locking carabiner using a double bowline.
- Use an alpine butterfly knot to create handles in the rope.
- Make sure the water is at least eight feet deep and clear of submerged logs and rocks.
Test for safety by having three people dangle from the rope at once. With centrifugal force, you’ll have to support three times your weight in order to hang on.