Vinyl pool liners have two main characteristics. They are sturdy enough that they don’t rip easily, and they are waterproof. The liner could, however, rip along its seam. You can relax because no sewing kit is needed. A simple vinyl patch can be glued onto the entire ripped area for the easiest repair that does not call for replacing the liner.
Drain the pool if necessary. You can drain the pool halfway if the tear is along the top half of the pool liner.
Measure the length of the rip down the seam with a tape measure, and then add an extra 2 inches on each end as well as 2 inches in width. These extra inches both long and wide will serve for better adhesion to the liner once the glue is added.
Cut a strip of the vinyl patch to the correct measurements, using scissors
Spread a thick layer of vinyl adhesive onto one side of the patch.
Hold the patch adhesive side down, and begin to lay it over the seam beginning at the top of the rip. Hold the patch 2 inches above the top of the tear before pressing down on it.
Roll your hands down the patch until it covers the tear completely. Hold it in place for several minutes to keep it from moving. Let the adhesive dry for about 48 hours.