Hi,
Now the daggerboards are installed and we have some experience. Daggerboards are 1.7m x 0.55m area below the hull. The case opening is on the midline and upper opening close to the hatch. Daggerboard case is supported by the ring frame between the mast and the hatch. The ring frame is extended to the case at the lee side. the foil is 55mm thick asymetric Speer section with carbon-plywood/foam core.
I tried to finish them to a high standard. They are quiet and there is no noticeable vibration.
We used one rudder only, so one way it is at the fwd end and the other way at the rear end. We managed to shunt with both foils down, then released the fwd one and pulled it up as needed. When we sailed rudder forward we kept the rear foil full down , lifted fwd foil all up and when going other way we managed too keep the fwd foil partially down. We are aiming to learn to use as little foil area as needed, now that we have already broke one daggerboard.
We spent three days sailing with the new arrangement. The boat was much more enjoyable to sail, less steering needed and easier shunts. Low speeds are not so critical anymore.
We also had some stronger winds, stronger than expected. I sailed too fast with too much sail area rear daggerboard almots full down, and it snapped at 14 knots. It made a loud bang. First I thought it was something on the rig but fortunately not.
Then handling the boat became difficult, not possible to gain speed and the boat wanted to go sideways.
I had a look at the stub and it had failed at the compression side. Great forces, must say. The daggerboard was made stronger than the Hrryproa design rudders. Next one will be solid plywood with carbon and glass.
The daggerboard case is ok.
Now I must make another pair of daggerboards, one for use and another for spare.
Regards,
Arttu