Aluminium foil foil rolling mills to the desired thickness, or by continuously casting and cold rolling. To maintain a constant thickness in aluminium foil production, beta radiation is passed through the foil to a sensor on the other side. If the intensity becomes too high, then the rollers adjust, increasing the thickness. If the intensities become too low and the foil has become too thick, the rollers apply more pressure, causing the foil to be made thinner. The continuous casting method is much less energy intensive and has become the preferred process. For thicknesses below , two layers are usually put together
Bruce foil available to drive movement without the crew needing to move their weight. The main disadvantage is that the sails remain upright and keep the full force of the wind available, rather than depowering with increasing angle of heel as happens with traditional foils. The Bruce foil also produces increased drag as a result of the vertical component of force, as well as a yawing force due to the off-center placement of the foil, which may require alteration of the steering system to compensate. Bruce foil A Bruce foil is a variant of the leeboard, consisting of a foil typically mounted