The rules limit the length of the boat to 12 ft, beam to 6 ft 6 in, an all up weight to 78 kg and a sail area of 10.4 m2. National 12s are sailed on all types of water from narrow rivers to the open sea. The class holds a national championships on an annual basis – known as Burton Week after the premier prize of the week: The Sir William Burton Cup – at various venues around the UK coast.