dam were opened as the tide rose and filled the mill pond, then closed to contain the water in the pool when the tide began to ebb. When there was enough difference between the water levels the miller opened the sluice gates so the water would run from the pond through sluices under the mill, driving the water wheels. There are two undershot water wheels with wooden bucket paddles. One water wheel is wide and the other is wide. Both have square shafts. The mill is a three-storey stone building with an attic and a slate roof. The building is five bays long and two bays wide. On the ground floor there is machinery for lifting the sluice gates and for the running stones. On the stone floor above there are six pairs of millstones, three driven by one water wheel and three by the other. The stone floor also houses the machine for cleaning the grain and the flour dresser. The grain hoppers are on the bin floor above the stone floor. The miller's house adjoined the mill, which was essential since working hours were any time in the day or night when the tide began to ebb. A sack hoist was used to lift grain to the attic, or garner floor. From there it was poured down to the winnower on the stone floor to remove chaff. The cleaned grain was then hoisted back up to the attic and poured into large storage bins on the bin floor. The grain was delivered from the bin floor through chutes to the stone floor, where it was ground to produce meal. The meal was then hoisted again and poured down to the flour dresser, which produced white flour and bran products. Grain was delivered to the mill by cart or by sailing vessels, and flour was shipped by sailing vessel. History Pembrokeshire exported corn to other parts of Wales and England in the 17th century. Carew Tidal Mill was at first used during the Napoleonic Wars to grind corn. In the late 19th century the traditional Pembrokeshire mills faced competition from steam-powered roller mills built in the port towns to mill low-cost corn shipped from abroad. At the same time the introduction of the railway to Pembrokeshire created demand for dairy farming. The Carew mill began to grind bones for fertilizer and to grind animal feed. It was called "dilapidated"