The daggerboards and how they work

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The daggerboards of this Exploder A class cat are Z10 type; the last evolution of z-shaped,  they give more stability and allow to fly a little earlier.

When on the beach we can put them in useful compartments.

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Cases are controlled with the blue sheet. Thanks to a closed-loop system below the trampoline we can control both daggerboards from any side of the boat.

Once inserted in the cases, we secure them with the red rope and a cleat at the top of the daggerboard.

When cases are all forward, we navigate in “no-fly mode” or “neutral”. The angle between the daggerboard and the hull is 90°; the boat has little lift but, more or less, it behaves like an A classic cat. While we push backwards the cases we entry in “fly mode”.

With medium wind (10-12 knots) we can put them at the level of the second hole. All these settings may vary also from the weight of the helmsman. The faster the boat is, the lesser we need to push backwards the daggerboards. We never push them beyond the third hole (2-3 cm) if we want to fly efficiently. The fact that we are flying doesn’t mean that we are fast.

Moreover, with the aid of little iron nails, we preset the lift that we want to have before going out.

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The seven golden rules revealed

These are the seven golden rules for foiling an A Class Cat, handed down from father to son.

  1. Don’t be scared
  2. Fly a hull to come off foils
  3. Sail boat dead flat or even windward heal to get on foils
  4. Sheet out a lot to get on foils
  5. Sheet in really fast as boat come up onto foils and accelerates
  6. Once sheeted hard and going fast, just keep boat flat, with sheet and steering any hull flying is slow
  7. Practice, practice, practice

 

A new breed of cat

The last three years have been of great development for the A-Class catamaran.

These boats can now literally fly on the water thanks to new set of daggerboards and rudders. The difference between floating or flying means 4-5 knots difference in speed.

In compliance with rule 8.1 and 8.2 (“no part of each hull or hull appendages below the waterline shall be less than 0,75 meters from the centre line” and “that movable and retractable appendages shall be inserted from the top or be capable of being fully retraceable into the hull”) there have been developed Z-shape daggerboards in conjunction with L-shape rudders able to produce enough lift to make the cat fly.

Even the shape of the mainsail has changed. They took some area from the top of the rig and put it down. The goal of these “decksweep” main is to reduce list and increase performance when the boat goes in laminar flow regimes (almost always).

Because of these recent developments the way to drive the A-Class speed machine has also changed. Actually we have to trim the main continuosly, especially in waves, and steering. If we have flat waters, we can lock-in our trim and simply adjust with the steering.

By trimming the mainsail on and off we basically put or release some downward pressure and weight on the boat. So, if the bows go too high i sheet the main in, otherwise i sheet out to get out of the water. With the steering we balance the boat when  in “flying mode”.

These new breed of A-Class cats are equipped with sliding daggerboard cases. We can increase the lift simply moving backward the daggerboard and so we can use different settings for different conditions. We can also increase or reduce lift by changing the position of the body. Even the way to use the traveller is changing: 20-30 cm from the centre going downwind is enough. These catamarans can bear away much more then classic A-Class when flying downwind.

The development are still running and i can’t even imagine what the future holds for these class of catamaran, the best has yet to come…