a couple of points about the design parameters listed in the article-

The structural aspect is certainly a huge issue but most designs I see tend to stick to very traditional sailboat design technologies where the hull structure and skin is used as an integral part of the staying of the rig and as a result takes on additional weight…whether through clever design or use of high tech materials or both it would seem entirely possible to create a framework built around and including the crossbeams that could support the rig and provide suitable beef for attaching rudders, boards and running rigging by itself, so that any beefing up of the hull structures beyond that needed to hold their shape could be kept to the points where the hulls attach to that framework, which will always be more substantial to begin with. The hull skin then becomes little more than a means of keeping water out.

But it is this part-

“The outriggers (“amas”) need to be very large to handle racing-cat speeds. The rule of thumb, if you’re designing a sailing trimaran from scratch, is that they need to be 120% to 200% of the displacement of the entire rig.”

-that I find puzzling in light of the fact that vessels like mono racing skiffs and sailboards regularly reach and even surpass racing cat speeds without the use of *any* outriggers (or foils). This rule of thumb may hold true for a boat designed around a kayak, but it seems to assume that ama displacement is the only available means of stabilizing a trimaran…it’s especially puzzling considering that the design featured places the crew away from the centerline- presumably to windward- and by default that leverage provides non-displacement righting moment. Sure, it requires physical exertion, but in a racing context that’s pretty much accepted as part and parcel of getting high speed out of a small boat.

Another factor that significantly affects the required righting moment is the leverage of the sails themselves that is always trying to push to boat over to leeward in a more or less traditional fore and aft rig…again, looking at sailboards there is another solution, which is to convert some of that wasted energy to lift by tilting the rig to weather-

“A direct consequence of the “Free Sail System” of Schweitzer and Drake is that in strong winds the operator inclines the sail to windward, rather than allowing the sail to heel away from the wind as is the case with all conventionally rigged sailboats. Because the wind-induced force of a sail (or aerofoil) is always perpendicular to its surface, when the sailboard sail is inclined to windward it has a portion of this force directed upwardly against the downward force of gravity. This upward force lifts the hull partially (or even completely) out of the water, thereby reducing its frictional and wave making resistance, and increased speed results. ”

http://www.wingo.com/chriswhite/tiltrig.html

-the above is a fairly complex means of achieving the effect; studies of crab claw designs and delta shapes show that similar effects can be had using those designs-

http://www.multihull.de/technik/t-slotboom_gb.htm

- combined with the lower aspect ratio and reduced weight aloft of those designs, this introduces quite a bit of range to the forces involved and many possibilities for adjusting the interactions between the various forces at work.

There’s certainly a lot to be said for traditional fore and aft rigs and they probably make the most sense overall for most recreational applications…but at the same time, their design development has almost never had anything to do with what is best for multihulls, and many of the features commonly thought to make them higher performance, like huge roached mains and super high aspect ratios, were developed within the context of strict racing rules designed in many cases for heavily ballasted boats- AND those rules in most cases were designed to limit performance in non-one design classes to make sailing skill the deciding factor in who won, rather than rewarding sheer boat speed born of technological superiority.