in whitewater at least, 45 deg became the norm 25 years ago (except for slalom where closer to 90 was normal). Then it shifted further and now 30 is pretty much

in whitewater at least, 45 deg became the norm 25 years ago (except for slalom where closer to 90 was normal). Then it shifted further and now 30 is pretty much standard though 0 and 45 are not unusual.