Acrylic can be easily bent while heated to a plastic temperature... that's how the pro's do it. But they don't use a torch, for that will never get it heated uniformly enough, and you will not get the fair curve that you want. If you can get the sheets
into an oven
, then uniform heating
can be done. Some friends talked a local pizza parlour into using one of their ovens to do theirs... worked well! Another, less easy means is a set of infra red lamps; anything that will heat it evenly and slowly. If you can get some scrap material from the vendor, you can experiment
with temperatures. I don't know the exact temp, but it isn't very hot.
Also, if you drape the limp new hot plastic over the old windows, you will get near to but not the same curve. It may be near enough that you can spring it into place, but maybe not. Again, some experimenting might save you some grief.
It isn't as easy as it looks, but I managed to get decent results on our previous boat some years ago.