WIG boat with wingsail

yeah, but following Flados points, the ONLY way to achieve 2-3 times wind speed is on a broad reach - with the wind on one side.

Now - that speed is made possible by the resistance of the daggerboards to the sideways pressure.

WIG lifts you off the water. Daggerboard is only partially submerged - you lose sideways resistance - you skate sideways and lose speed.

You need some serious math before you even think about designing such a specialist hull.

Have a serious think about why the sketch at
http://jackyamaguchi.wordpress.com/2...by2-nautica-1/

is impossible. It has to do with the only foil providing sideways resistance being out of the water.

 

Getting lift is not the problem. Supporting the boat with minimum drag is the issue.

The apparent wind/true wind speed ratio is sin(gamma)/sin(beta), where gamma = point of sail (zero = head to wind) and beta is the apparent wind angle measured between the apparent wind vector and the boat's course through the water. The boat-speed/true wind speed ratio is sin(gamma-beta)/sin(beta). Say beta = 25 deg and gamma = 135 deg. The boat will be going 2.2 times the speed of the wind. The apparent wind speed will be 1.7 times the true wind speed and 75% of the speed of the boat.

In order to achieve beta=25 deg, it needs to have a high lift/drag ratio. If one assumes the aerodynamic and hydrodynamic drag angles are the same, that means an aerodynamic drag angle of 12.5 deg and an aerodynamic L/D of 4.5. The L/D has only the horizontal lift, but has to include the drag due to both the horizontal lift and the vertical lift. Drag due to vertical lift appears as just a parasite drag to the sailing performance.

 

That's why there would be a vertical parts at the ends of the foils which will be still submerged to have sideways resistance when the boat is in fly mode with both slanted foils out of the water. Another possible way would be having a centerline daggerboard in the bow part of the delta wing, while having foils only to ease the transition to when whole lift is by the wing.

 

And you would call that .... longer foils !!!

yeah ... but - you would only have enough dagger in the water to get to speeds where the WIG effect could be created. If you had more than you needed, its unnecessary drag.

so ..

when the minimum board lifts out of the water ..... you go sidways and drop back onto the surface.

Once again ... have you done any math on this ??

Admit it - its just a 'gut feel' with no science at all.

 

Same as how much of maths & research applied compared to "gut feel" in any of those cgi's & drawings of futuristic / "possible" concepts? Yet, authors seem enough convinced their designs would work exactly like they appear on the drawings that took some fair time to get the viewer in WOW! mode.
At this stage I'd like for my model to have an enough promising arrangement with obvious flaws as less as possible in the eye of experts.