John
I remember a similar discussion re: the 18's chines and vortex mgmnt.
Bonus for the canted tails? Additional pitch stability; off vertical, there is an up/down vector to augment the elevators. On the cat, the rudders are both "in" (pigeontoed) to aid rotation at the bow. The 18 is a very pitchy machine.
The cant also aids stability in the roll, think dihedral.