You are as good as your material. Equipment is subject to changes, new rules, new materials, new ideas and new thinking. New ideas are also not always necessary. This is also an important lesson.
I compare my boats to precision Formula 1 cars.
For example the A cat, 5.48m, 2.3m wide and a 9.1m mast the complete boat ready to sail weighs 75kg(165pound) with 14m2 of sail. Set the boards to 0.4 degree’s toe-in and you are slow set them to 0.7 degree’s and you are fast for the C-boards. Changing the alignment of the daggerboard 2mm to the center line has great impact. Mast development, bend characteristic, resistance against bend for a person who weighs 85kg. So make the mast to soft and the leech will open to early, make the mast to stiff and you have a difficult to sail boat with no much depth range in the sail.
Foiling is achieved when the hulls are no longer in displacement mode and the complete weight of the boat is carried by the underwater foils (rudder and mainfoil /daggerboard). To lift the boat out of the water is easy, to make it stable requires a lot of knowledge of the different variables.
To address the a rudder and its feedback:
Imagine a car which does not steer very nice (now considered a rear wheel drive phenomenon). A nice steering boat has to do with the rudder: profile shape, outline, construction and rotation geometry. Again a matter of millimeters, a good example is on the Gunboat Tribe (16.000kg) boat 62feet long and 30feet wide. The rudder had moments where it lost control (over compensated). We addressed the situation and changed the compensation and the boat handled afterward like a beauty.
Materials, craftsmanship, shape philosophy and a huge amount of testing makes for fast sails. It is all started in “De Piet’s garage” working days and night by hand has led to a strong base of understanding all aspects of the trade. Times have changed and now include designing by hand side by side with the computer followed by checking profiles and behaviour with digital camera’s and videos and pushing the limits with fabrics and new theories.