Interesting article in the recent Sailing World magazine on the current sailing speed record holder.
It is described as a tri foiler type with wing sail though would call it more of a proa which has a long lever arm {crossbeam} and pod set to windward to house the crew inside protecting them at high speeds.
The key to a multihull type craft wrestling the speed record away from boardsail type craft is the effect of beam and righting movement to relative weight and sail area, -obviously the multihull with its much larger beam and righting lever arm has the advantage, unless someone finds a way to attach an extended crew pod racks or wings off a sailboard.
This was actually attempted in effect nearly 30 years earlier here in MI by the Geougeon Bros, -known for West system boat building epoxy, with their run at the sailing speed record with their planning hulled similarly conceived proa SLINGSHOT . Crew would scramble out from the main hull towards the pod some 30 feet away as pressure on the sails and speed increased giving the righting lever arm and weight measured in ft lb. to counteract the forces on the sail.
One main difference is the course, the foiler requires a perfectly flat water condition with no wake and perfect alignment to wind direction, The Slingshot trials took place on Lake St. Clair, part of the great lakes filled with ocean going sized ships, ore carriers, and large powerboats of all types, -quit a difference but very similar concepts using the proa configuration and large righting lever arm and huge effective beam . . .
-Catamarans similarly have a huge advantage over monohulls partially for this reason, added beam. Some planning type skiffs with large racks or wings for the crew to provide this similar lever arm is the exception but same speed theory along with weight to sail area and hull planning capability and other aspects of proper design.. The lever arm of added beam and ft lb. of righting moment are measured by taking the beam, or distance and weight from the center of buoyancy or leeward hull. In cat design even adding one and a half feet of beam say from 8.5 to 10 ft of beam, one would add the weight of crew 300lbs and partial hull and boat weight 100 lb. { just fictional average } at 400 lb. times 1.5 = an additional 600 ft lb. of righting moment over the same crew and similar weight cat with an 8.5 beam as soon as the cats begin to fly a hull, quite an advantage as the wind increases in speed potential having the additional 600 ft lb. driving the boat forward on the 10 ft beam cat. .The most noted real life example of this larger beam effect on potential speed was during the last Olympic boat trials in selecting Olympic Classes and catamaran design for use in the 04 Olympics. The Tornado with its 10 beam sailed away from all 8.5 cat designs in the 15 mph. Av.winds.
-One of the most interesting experiments I saw in relation to added beam and its effects of catamaran speed was during the 87 and 88 Worrell 1000 , / World 1000 –open to any 20 ft cat. Two different boats were entered with 10 racks mounted, one on a traveler on an extended N-5/8 which became the 6/0, very interesting looking, but do the math, a 200 LB crew out an added 10 of effective beam adds up to 2,000 ft lb. of added lever arm counteracting the force on the sails helping drive it forward, ---no wonder this boat was over the horizon from all others within an hour of leaving the beach with its added huge lever arm and beam advantage.
The other most easily understood example of beam effect of cat design are the Supercat Arc and RC series of larger cat designs by noted designer Bill Roberts , these large powerfull cats with larger beam hold most major distance race records and have for some time. I had the pleasure of talking with Bill briefly this year as he stopped by briefly at Jenson Beach during this years Worrell 1000 just before the start . I also own a Supercat and am a big fan of his design work and development of so many good ideas applied.
Evan he ,with his jet engine engineering background will jokingly tell you –{you do not have to be a rocket scientist to understand the effects of larger beam and its positive effects on increasing potential speed in cat design. }
Have fun and sail safe
Carl
