To be able to pass through navigable channels without the risk of getting stuck, either in gondola, vaporetto or any other type of small boat, it is necessary to respect the navigation limits marked with the bricole or mooring posts (groups formed by a dozen stakes tied in a beam). These bricole have white markings on the top, but only on the side of the waterway, and some painted numbers that are used to locate them on maps and for identification by maintenance services, since that the movement of the tides damages the wood of the piles and makes their renewal necessary every 20 years. The dame signal the entrance of a canal or the approach of a crossing. They are also piles tied together forming a beam, but smaller than the previous ones, since they are formed by thinner piles and in smaller quantity (usually three or four). The paline are thin tie-up piles formed by a single element of wood. In them private boats are tied. The prettiest are painted with brightly colored spiral bands and stand proudly in front of the main palaces of the Grand Canal. Formerly reserved for the nobility, the colors of the paline were those of the families to which the moorings belonged.