Super rusted nuts on my Hobie 18 rudder

I cant get it un-done with brute force, the nut's metal just gives way.  Seems like I need to cut or drill it, but not sure how that can be done really.  They are recessed a little bit in the rudder housing, so I dont think I can get a flat cut in with a hack saw. They do still turn though, so maybe drilling the center out would work?  Probably take forever though without a drill press.

How about if you first cut it nearly flush (nut side)? Then there would not be so much to drill out to release the nut.

A drill press would certainly help, but I think the drilling could be done by hand, if you take your time and start dead-center on the bolt...

I guess I really have no good tools to do the job, so i'm asking Tedski for help    It may be doable with two people, I just know I cant hold one side and turn the other no matter how many ways I have tried.  Crazy how easy the other two bolts came off.

Maybe a small pipe wrench. Vice grips tend to squeeze the nut making it harder to turn. Can it be heated? Drilled out? Liquid nitrogen? Getting the nut warmer than the bolt may cause it to be a little bigger than the bolt and break the grip it’s got.

Dremel tool with a cutting disk.  Cut the bolt and nut length wise and will split the nut.

interesting that the bolts look fine and the nuts are trash.

I'd soak it in PB blaster or similar for a couple days, then hit it.  I've never had much luck cutting, but that's me.  Drilling through the bolt head may work also, over size drill bit until the head falls off.

Thanks to tedski the nuts are off and I can re-assemble my rudder system again with all new parts.  Thanks Ted!  . Impact drill with the Irwin bolt extractors made quick work of that problem.

Thanks to tedski the nuts are off and I can re-assemble my rudder system again with all new parts.  Thanks Ted!  . Impact drill with the Irwin bolt extractors made quick work of that problem.

Impact and Kroil are a good combo for sure!