hello there,

I didn't read all the responses, but here's what I know:

drill a little hole in the broken piece left in yuor hull.

make an opposite thread (ccw) in that little hole that is in the little broken piece.

screw a screw into that hole & tighten it until it starts to turn the broken piece until the broken piece is out.

yes, you need to get that tool that makes threads. it has to be with a diameter that is small enough, & it has to be a ccw thread. never saw one, never did it, it's just the way I was told broken screws are taken out.

good luck,

Erez