It is a replica of the Nocturlabio and Abacus of Tides of 1570, signed by Humphrey Cole. This instrument is currently in the British Museum, London. One of its faces is this Abacus or computer of Tides and the other is a Nocturlabio. The abacus or computer of tides is used to calculate the hours of the tides. The tides with their constant change of the level of the waters have effects of great importance for the navigation, for the ports and for the fishing.