The A-Class design has over time converged to a single sail rig using a lightweight carbon mast of about 9 meters length and using lightweight pentex or
Kevlar sailcloth. The hulls and beams are often made out of carbon fibre as well, although homebuilt wood or composite materials are still seen on the race circuits. In the decades since their foundation, the A-Class has gathered a significant international following and it has class organisations in many countries around the globe. Their world championships often attracts around 100 boats and sailors. It is also a class that still contains a significant portion of homebuilders, although their numbers are decreasing with every year due to the skills required to make a competitive boat. However, nearly all A-Class sailors tinker with their setups and boats. As it is a developmental class and the rules do allow so much variation, it is paramount that a top sailor keeps experimenting with new setups and generally tries to improve the design even more. Because of this general character of the class, the A-Class is often leading over other catamaran classes in terms of design development. Over time these other classes copy new findings for their own setups. Examples of such developments are: the carbon mast, the squaretop mainsail, the wave-piercer hull design and in general the use of exotic materials. In 2017 with the advent of practical foiling designs, the IACA divided the class into an Open (Foiling) division, and a non foiling Classic division for boats with straight or C-shaped foils, and with different class rules to prevent foiling. The two have slightly different SCHRS handicaps, the Open being 0.978, the Classic being 1.008. This allows close racing to continue, and many older boats are still competitive on the Classic circuit particularly. ==Builders==