How do you make modifications to a home you do not own?  For example, the houseboats we rent from Paradise Point for ephemerisle do not come with curtains around the bunks.  People jury rig rope/sheet curtains with duct tape, but this risks damaging the finish of the paneling on the boats. 

One possible solution is to use suction cups, and tying a rope between the suction cups.  Here’s a few of varying strength and prices:  

Addahook The Heavy Duty Double Locking Suction Hooks (holds about 10 lbs):

Generic Uline Industrial Suction Cup (holds 100 lbs)

4 1/2″ SeaSucker with Aluminum Handle (120 lbs holding capacity)

Check out the SeaSucker website for many more ideas on how suction cups can be used.