[B_and_D]

Maybe an old-fashioned way would work...take a needle and thread (white carpet thread) and sew back and forth, crossing over the rip and back, and going under and over the fabric where it is ripped overlapping the rip by about an inch and a half.

Got patience? You may not need a patch? How frayed is the cut?

You can buy a sturdy craft needle at most places that sell those sort of things.

Atomic tape? Sounds like something that we must have....

Sounds like a challenging repair. Let us know how it comes out.