Calshot Spit is a one-mile long sand and shingle bank, near the village of Calshot, located on the southern bank of the open end of Southampton Water, on the south coast of England.At the end of the spit are Calshot Castle (built by King Henry VIII), an RNLI lifeboat, an NCI station, several slipways, a former Royal Navy and Royal Air Force flying boat station and Calshot Activities Centre.