Take the rig from any modern cruising catamaran and use it to push a longer main hull with the same overall weight, and the result is greater comfort and speed. The Pacific proa configuration uses sails that would be too small on a catamaran of the same length, yet work well on the proa.

Pacific Proa Advantages:
The Pacific proa gets advantages over the catamaran by using the same weight of materials (cost!) to create a significantly longer main hull with higher speed potential:

• a longer hull is more easily driven for fast ocean passages and more appropriate to the scale of large seas offshore.
  
• transferring up to 100% displacement to the single large leeward hull as the windward hull lifts results in smooth, comfortable speed with minimal wetted surface.
  
• when pressed for maximum speed, the longer leeward hull with similar rig and no additional lateral stability (the ability to resist tipping over sideways) results in greater longitudinal stability than a catamaran; instead of pitchpoling, the Pacific proa will roll gently onto the leeward pod.
  
• a small, lifting hull to weather for stability is mechanically easier and lighter than connecting two hulls of equal size and weight (catamaran) or using "floats" of 100%+ buoyancy on either side (trimaran). While modern materials and methods make structure less of an issue, the crossbeams on a Pacific proa are less stressed than a catamaran of similar displacement.
  

For the very same reasons, however, it is also true that the Pacific proa carries much less weight for it's length than a catamaran.

• Where the catamaran has broad flat transoms aft that carry weight well and reduce pitching, the proa is pointed at both ends.
• The proa's main hull might be narrower than the catamaran, using a length to beam ratio of 17:1 for speed.
• Since there is only one large hull, adding length to a proa returns less accommodation volume and weight carrying capacity than the same length added to a catamaran.
• extra privacy afforded by two hulls for accommodations

For these reasons, a 21 meter (69') proa has barely the same capacity as a 43' catamaran and significantly less accommodation volume and only half the displacement of an 18 meter (59') catamaran. For the same price and using the same size rig as a 60'+ catamaran, a 90' proa with superior performance potential could be built.

Accommodation plans for large proas remain a challenge while cruising catamaran plans have been widely explored for decades.