Just took the short trip to Catalina Island from Newport Beach. For those not familiar, it’s about 25 miles, depending on point of departure. Like the boats from other ports (Dana Point and San Pedro) that make the runs to/from Catalina, the hulls are catamaran designs. Well, the trip over was very rough, numerous pukers. So, I’m wondering about hull design, specifically why these boats are all catamarans? Obviously, the owners/operators feel this design is best. But what is the definition of “best?” Stability? Fuel consumption? Passenger load per size of hull? Wouldn’t a V shaped hull be a smoother ride?
I believe catamarans are faster and have less drag.
I thought it was 26 miles across the sea. 
Catamarans roll somewhat less.
A single hull is always going to be at a single point in the cycle of a passing wave, that is to say, trough, rolling left, peak, rolling right. A catamaran, on the other hand, will have one of its hulls in one portion of the cycle, say rolling left, and the other in a different portion, say rolling right. Thus the effects of the wave on the hulls tends to cancel themselves out. At least in theory, that is. A lot depends on wavelength and wave angle of incidence to the hulls, but on average you will see some benefit.
As for pitching, that is dependent on hull length and a catamaran provides no benefit.
You’re obviously no spring chicken. 
Catamarans are faster than monohulls (more hull in contact with the water) and power cats are more stable laterally - less rolly - than power monohulls.
powerboat or sailboat? If the former, catamarans are a bit less “rolly” (side to side) and, most importantly, have that “tunnel” running down the center. Like a hydroplane, the air rushing through there helps keep the hull planted on the water at higher speeds.