Hi Wouter,
The SC mast section was designed in 1978. It has a design point chord of 6.5 ins and a max width of 3.25 ins for a slenderness ratio of 2.0. The cross sectional shape, width distribution, was obtained by using a NACA 0050 foil section. When compared to Hobie, Prindle, Nacra and Tornado masts of the same period, the SC section was the only one with a thickness to chord ratio as low as o.50. The actual absolute thickness, 3.25ins, and chord, 6.5ins, minus the sailtrack area determined the volume per unit length of the mast that was required to keep a 12ft wide by 20ft long catamaran from going "turtle" in typical turnover conditions. I tried slightly smaller mast sections, Tornado, but they let the boat go "turtle" so a new larger mast section was required to prevent this 12ft wide two person boat from going "turtle". It had a slenderness ratio of 2.0, better than any of the other boats of its time, and it would not let the SC20 go "turtle".
When I designed the SC product line, I was sailing in the Atlantic Ocean off Palm Beach, Florida. There are no bays or protected waters to sail in. There are no islands a couple of miles offshore to sail downwind of. There is just the Atlantic Ocean with the Gulf Stream marching North at 4 knots. This SE coast of Florida is "BEACHCAT CATAMARAN GRAVEYARD". I felt it was morally wrong for me to sell a beachcat to the public that would "turtle" when turned over in that ocean. I also felt it was morally wrong for me to sell to the public a boat that could not be righted by the people sailing the boat. That is why every SC and now ARC product ever built has a righting system as a standard part of the rigging. No other boat builder does this and some have paid the ultimate price for this decision.
Fast and Safe Sailing,
Bill