Assymmetric hulls on (displacement) power cats tend to generally be pretty directionally stable.
I found this out with the cat in my avatar - 49' long, and 16' beam - when one of her engines packed up, she still proceeded happily in a straight line on one engine with no offset helm required - and I was thinking she would want to go around in circles like the one legged duck might tend to do.....
Its the same with sub 10mtr planing cat hulls, a lot of fishermen use the Cheetah marine design of cat with just one engine on one of the hulls to no ill effect.