North Sonar Alloy Foil mastNorth Sonar Alloy Foil mast The new refined, thicker walled aluminium foil section gives the best balance between light weight and increased strength for higher loads. The forgiving 55cm mast is suitable for skimming just above the water and easy recovery ideal for learning to foil or for shallow waters. The 72 cm (AF72) Mast is 30% stiffer than the AK70 mast yet only 13% heavier, and is ideal for shallower waters, and prone surf foiling. The 85cm