Two Sluice gates are apparent on early post medieval mapping between 'The Great Pent' (now known as Wellington Dock) and the main eastern harbour at Dover at the western end of the Cross Pent Wall (now Union Street). On William Eldred's map, dating to 1641, the two sluice gates are labelled. The eastern sluice is labelled 'The Old Sluce' while the western is labelled 'The Newe Sluce'. (1)

Construction of the Great Pent which was designed to retain both fresh and salt water at high tide and, by means of sluices, control its outflow at low tide, was undertaken on the most part in the summer of 1583. The controlled rush of water would then scour the harbour and clear its mouth of any accumulated shingle and debris. Thomas Digges, who was an engineer and mathematician and who had studied the nature and construction of the ports in the Netherlands, was one of the most active and esteemed combatants in the design process of the new harbour and produced a number of important plans, which included depictions of the sluice within the cross wall. (2)

An early plan of Dover Harbour by Thomas Digges, which dates to 1581, at first glance shows the harbour (or absence thereof) as it was after the creation of Clerks Pier, Thompsons pier and Paradise Pent, but before any other major works were undertaken. A closer look however reveals a fine line starting from just north east of the river mouth, running south-west about half way towards the Paradise Pent, and returning at a slightly obtuse angle to join the cliffs under the Western Heights. (3)

The first definite appearance of the Cross Pent Wall and sluice gates is actually on a map which was drawn (again by Digges) just after the above mentioned, in c. 1588. On here the entire extent of the Great Pent is clearly depicted, including the long wall on its seaward side, the cross pent wall and associated sluice gates, in a form which is recognisable on later mapping, for the first time. (4)

Another map by Digges, entitled 'The State of Dover Harbour with the new works' dating to 1595 expands upon the work completed on the Great Pent in the 1580's and shows the finished harbour after all of the 16th century work on it had been completed. This plan represents a precise and very detailed example of an early cartographic source. The Pent, Cross pent wall and sluice gates are all numbered and labelled on this map. (5)

Further maps which include a depiction of these sluice gates include another which may be attributed to William eldred and which dates to 1631 (6) and that by Foquet dating to 1737 (7)

<1> William Eldred, 1641, The Platt of Dover Castle Towne and Harbor (Map). SKE31804.

<2> Stephen Johnson, 1994, Making mathematical practice: gentlemen, practitioners and artisans in Elizabethan England (Monograph). SKE32014.

<3> Thomas Digges, 1581, The State of Dover Haven (Map). SKE31984.

<4> Thomas Digges, 1588, Plan of Work at Dover Harbour (Map). SKE31986.

<5> Thomas Digges, 1595, The state of Dover Haven with the New workes (Map). SKE31987.

<6> William Eldred (?), 1631, Plan of lands belonging to the Priory and now to Master Buffkyn (Map). SKE31988.

<7> J. Foquet, 1737, Plan of the town, harbour and fortifications of Dover (Map). SKE31991.