Styrofoam perogue repair?

once you break styrofoam it loses all strength so no, there isnt much of anything you can do to restore it like it was.

now if the break is in half from side to side, you layer enough fiberglass on top and bottom extending about a foot passed where it broke, you can fix it.

now if the break is in half but long ways from stern to bow, if you layer enough fiberglass on top and bottom extending to cover across the entire bottom surface, and do it from both sides top and bottom, you can fix it.

but often with the amount of the work involved, its easier to just glue the old one back together and use it as a mold to build an all fiberglass perogue from scratch that will be stronger yet still be feather light