A kitesurf board works in a similar way to the kite-sit, we use the upwind to gain ground against the wind, on the kitesurfing board if we put more weight on the front foot, we gain more speed going downwind (derive), when we use the back foot, the back of the kitesurfing board sinks and the rythm slows meaning that the board does not glide so much, changing the direction of travel, bringing the kite towards the end of the wind window allows us to go upwind facilitating the luff.
In kite-sit the main difference from kitesurfing is that the profiles of the two floats of the small catamaran form keels like those on the kitesurf board, and the technique of counterweight, putting weight on the front foot or the back, is done in a different way.
To move the boat to go upwind to the right, guide it to the right, we move the foot out of the right stirrup, bend the knee and move the bottom to the right of the saddle while we try to shift all our weight to the right. Tacking to the left is the same but creating counterweight to the left
Regarding the size of the kite, we do not have to worry about sinking due to lack of power, the kite-sit floats at all times. So we need a kite to give us enough power to drag us while we turn, which is the time the boat shows more resistance. As mentioned the boat does not sink making it very stable at low speed, as the speed increases, piloting becomes more difficult, for this reason we recommend using a kitesurfing kite which is smaller than if we were practicing with a kitesurfing board.
For more information on the upwind technique you can check in turn the upwind kitesurf board.