I have purchased No More Nails (MN) in the past, however I much prefer the Power Grab. It holds objects in place instantly and when dry have never had it lose any adhesion.
Also, I had added a tension-mounted shower curtain rod in our 13' Scamp
. The flexing while towing caused it to shift and fall
, so I mounted closet rod cups on the walls where the ends of the rod would be. Voila! Removable shower rod and the half-inch lip on each cup prevented the rod from coming down on its own.