yes, big offshore "conventional"-type rods do have a large load, but these blanks are heavy and can absorb the twist. plus, you have a gimbal and you are generally strapped into the rod/reel.
the easiest rod to see rod twist is a bass or trout rod build as a typical conventional. put a reel on it, some line thru it and bend it at least 90 degrees. you will see the rod tip torque left or right as the line tries to get to the bottom of the rod, but can't because of the guide setup. so, the blank torques as it is not powerful enough to stop the line from getting to where it wants to go.
unless a customer specifically requests a "typical conventional rod" and i cannot change their mind, all of my boat rods are built spiral now.
risaa/ne saltwater fishing show link -
http://www.nesaltwatershow.com/