In the Trifoiler article there is only half a paragraph about "L" foils:
What Makes Them Work So Well By Greg Ketterman Multihulls Magazine May-June 1994
"We have continued to pursue our L-shaped foils for many reasons. They are smooth and simple, and they have no moving parts below the water. Wing tips and "T" connections generally cause turbulence and drag. With our L-shaped foils, the aspect ratio of the horizontal section effectively adds to the aspect raio of the vertical section, and we have only one wing tip that creates losses. Sure, there is more stress in these fois, but modern materials can handle the stress without any problem."
There's another interesting (but unrelated) segment:
"In our research we discovered something that is surprising. The amount of wind required to get onto the foils is not sensitiveto the size of the foils...(supressed)... This is surprising because with airplanes, if you have a larger wing then you can take off at a lower speed and less power is required. Sailboats are unusual vehicles as they have the ability to increase their power as they accelerate. The power of most vehicles is fixed and therefore the thrust decreases as the vehicle accelerates; however, with a sailboat the thrust, or driving force, remains nearly steady as the boat accelerates. Since the thrust is steady and the speed is increasing, the power generated increases, magically. Once this is understood, then it makes sense to make the foils relatively small to yield better high-end performance. The top seed and efficiency of the boat are somewhat sensitive to the size of the foils. Our foils are surprisingly small..."
There is not much about L foils in Cogito's article as well:
The Aussie's Little America's Cup Reign is Sunk by Christian Féurier Multihulls Magazine Jan-Feb 1996
"As the Australian early summer had been abnormally breezy, th Americans tried new rudders, L-shaped inside, in early January. Probably to try to stabilize hobby horsing in choppy seas, or reduce pitchpoling risks. They woked perfectly, but the cost was certainly an increased drag and they never used them."
PHOTO of Cogito flying a hull to show the L rudder with the following legend:
"The L-shaped rudders workd perfectly in choppy seas to stabilize the boat, but were not used in the races."
These were my sources. Summaries of real life experience. Your comments about L foils effective aspect ratio are very wellcome. Another view of my rudder's foils is attached.
