Hello, Mauro
Before making any firm suggestions, it would be nice to know what sort of winds and water you are to sail in, and with what sort of crew.
It would also be useful to know where the mast sits (distance from bow) and its height above deck level. Is Kingfisher 20+ much different from Kingfisher 20 ( ..found in Sailboatdata.com...)?
On small boats, I have found it best to use a big sail area to let me sail well downwind, and then use a moderate camber of just 8% in the horizontal panels. This means that I can carry almost as much sail upwind as downwind. On small boats, hoisting and controlling the sail is no big effort. As boats grow bigger and heavier, it may be difficult to find space (or muscle power) to set as big sail as one wants. That is when I suggest increasing the camber to, say 10 or 12%.
When fitting my first blue cambered panel sail for my Malena, in 1994 (see NL 30), I knew the solid wooden mast was too short. I still made a ‘full-size’, 7-panel sail for her, but then I rolled up the lowest panel, and sailed around with six panels that summer. Next year a new hollow mast was ready, and the seventh panel came into use.
Maybe that tactics could be used on your boat as well? Now I checked. If we start with one of my master sails, the one at AR=2.20 and remove the lowest panel, and then scale it down until B=3.65m, the AR will drop to 1.94 and the sail area to 20.1sqm. It will look like a close cousin of Frøken Sørensen’s sail, only with six panels. Then, later you may find that you can fit a taller mast and set a seventh panel. This will bring the sail area up in 23.4sqm and the SA/disp. to 19.4, which is not bad. Moreover, the sail’s fairly high AR will give a tall leading edge for better upwind performance.
Just a thought.
Arne

1994 1999