I used a massive pot, really huge, and I got some of the bend out. I recall that at the time, the supposition was that ISW had used the plans from the Floating Drydock which printed with that upturned stern, although it wasn't correct that way; it was a printing error. I don't know if that's true, but that's what modelers said at the time.

If you get a hull like that, another option would be to use a cutter and make little slices in the hull, port to starboard, and then use those as almost like an accordion to heat and bend the hull back flat. Then, fill in the slices with your putty or filler of choice. I considered doing that, but was afraid of the resin dust.