Lower center of effort allows larger sail area. Smaller dual masts are easier to raise and lower than a single larger mast. Compression loads are removed from the main beam and no forebeam is needed.
Wishbones reduce sheet loads and allow reversal or flow over sails.
Aluminium is a very consistant engineering material with excellent mechanical properties and a long service life. Its is easily anodized in a variety of colours such as grey, gold, red, green, blue and black and such a finish holds up well in a marine environment. Aluminium is available in economical custom extrusions and can be readily stretch formed into complex shapes. The primary structure is designed for low labour input manufacturing. Custom extrusions are used as appropriate to reduce costs and integrate function.