A really interesting thread of comments has developed about rudders and other movable appendages on the French aluminum expedition yacht from Boreal.
Jean François Eeman, one of the partners at Boreal, has been kind enough to send us this picture, which will help to illustrate his comments:
Going windward : as soon as you have more than 10-12 knots of wind you start lowering the downwind daggerboard. When a puff arrives, the boat comes up closer to the wind and heels more immersing the daggerboard more and bringing the boat back on its initial course.
The systems works : when the boat is well trimmed she can goes windward for minutes (sometimes 30 min) without you having to touch the steering. In rough conditions you can see its impact on easing the work of the pilot by checking the amperemeter.
Going downwind in windy conditions: you lift pretty much the whole keel, moving the anti-drift center aft. And you lower the two daggerboards… The boat is like on rails