What is "slipknots"

Usage examples of "slipknots".

Parker tied the ropes with slipknots to the railing waist-high beside the catwalk, then removed the metal weights from their wooden racks tied to the ropes.

Parker raced along the catwalk, kicking off the iron weights and yanking the slipknots on the ropes.

Parker grabbed the ropes on the last two, yanked the slipknots free and held onto the ropes, and was yanked up into live air, rode up through darkness toward the ceiling, his shoulders and back grinding with pain, not wanting to be forced through this.