Using a hammock attached to a tree on Sabbos
Question
Is it permissible to use a hammock attached to a tree on Shabbos?
Answer
Dear …!
Using a hammock attached to a tree is forbidden on Shabbos. However, if the hammock is not attached to the tree, but rather to a peg driven into the tree, or even a loop around a branch of the tree, it is permissible to use it on Shabbos without a problem.
If the hammock causes the tree to shake or move, it is forbidden to use it at all.
However, even in the case that the hammock is attached to a peg or rope, which is attached to a tree, even though it is permitted to use the hammock, it is forbidden to hang it on Shabbos, as this is considered using the peg or loop attached to a tree, and using trees is forbidden on Shabbos.
If you wish to hang or to remove the hammock on Shabbos, you can drive a peg into a tree, put a rope around it, and then it would be permitted to attach the hammock to the rope and to remove it. Alternatively, you could attach a rope to a thick tree branch, then attach another rope to the first one, and then you’d be allowed to use the second loop on Shabbos.
Source
Shulchan Oruch (section Orach Chaim, ch. 336, Paragraph 13)