thank you for your replies. The celling is drywall as well so not much help there. Nothing but metal studs behind the drywall there.
I might have to just forget about sleeping in my hammock then.
I found this kind of bolt : http://www.google.com/imgres?q=toggl...w=1280&bih=738
People around the web suggest using this to hang televisions on drywall with metal studs. Does any of you think this might be a solution? or can flat screens and hammocks not be compared.