I get the feeling that wands are getting to be a little old-school. There is a lot of complication with the linkage mechanisms and getting the action right takes some effort (unless someone has worked all that out for you ahead of time). I'm guessing the self regulating foils are going to be the future. Back when foiling first started on power boats the foils were self regulating and we've seen that theme through everything from Hydroptere, the recent America's Cup, and even Dave Carlson's creative beach cat adaptations in the 80's. Here's a picture of Alexander Graham Bell's record setting hydro foiler built in 1919. It held the foiler speed record at 60 knots until the 1960s. Even it has a foil system that reduces the amount of foil and the resulting lift as it gets faster and higher out of the water.



The trick with a self regulating foil is to do it efficiently. Looking at that picture, you could understand how draggy all of those ladder foils can be. Hydroptere improved on the theme with a single tapered, inward canted, foil. As the boat lifts higher out of the water, it has less foil in the water and that water born foil has a shorter chord for less wetted surface area. The America's Cup testing determined that the V-shaped foil offered a stability advantage with the two somewhat opposed lifting surfaces in the "V" working against each other. That V foil is also self regulating and starts reducing lift gradually as that V pierces the surface.