On Wednesday, 8 November 2017 18:29:02 UTC, wrote:
I need to capture a half-feral cat with a serious medical problem. I have a large wire cage that's not designed to be used as a trap. If I tie string/rope to the open door, pass it through the wire cage and run it along the ground, it would be possible to wait and pull the string once the cat enters. This won't work unless the door closes and at the same time a knot ties it shut. The knot needn't hold long, 10 seconds against a large strong cat should do the job. Question is, what knot should I use?


NT

Make a sliding noose which includes the door open edge and the adjacent frame, so that when the free end is pulled, the door shuts. Then lead the free end up and over a pulley or wheel above the cage (this pulley or wheel could be mounted on a temporary structure, such as a step-ladder), wait for the cat to enter the cage, then pull the free end until the cage is lifted in the air, where the weight of the cage and contents will keep the noose tight and the door shut.