Nieuwediep was a canal and harbor. In about 1800 the major naval base Willemsoord was constructed west of it, soon followed by a major commercial port. After World War II, Nieuwe Haven Naval Base was built on reclaimed land east of the Nieuwediep, and the Nieuwdiep's source and mouth were dammed off.
Nieuwediep harbor
A trench in the Wadden Sea
Nieuwediep started out as a trench in the Wadden Sea, called , which translates as 'the new canal'. After a polder had been made near Den Helder, the Nieuwediep ran very close to its eastern dyke. When the Nieuwe Diep became a harbor, 'Nieuwediep' became one word. The determiner 'the' (Dutch: ) was often used very consciously with regard to Nieuwediep. Plain 'Nieuwediep' tends to refer to the old port, the old navy base, or the settlement near the canal. 'The Nieuwediep' refers only to the stretch of water, also as part of the current Port of Den Helder.
Need for a harbor near Den Helder
In the seventeenth and eighteenth century it became increasingly difficult for big ships to regularly sail to the Dutch cities on the Zuiderzee. Many ships therefore anchored in the Roadstead of Texel, where a lot of transloading was done by vessels that brought the cargo to Amsterdam and other cities. While these smaller vessels were waiting, they anchored safely in Nieuwediep, which was well protected by a shoal.
The importance of a protected base for the Dutch navy and commercial shipping near Den Helder was stressed by the Fourth Anglo-Dutch War. The Nieuwediep was an ideal location, but not deep enough for warships and East Indies ships, because there was a bump in the mouth of the Nieuwediep. A plan to make a useful and safe harbor for warships in the Nieuwediep was then made by: Captain W. May, equipage master of the Amsterdam Admiralty; C. Brunings, inspector general of the rivers; Surveyor B. Goudriaan, L. de Berge and P. Haage. They specified that such a harbor: should be big enough to lay ships at a sufficient distance from each other, should keep the ships safe from weather and Ice shove, should be deep 20 feet deep at ebb at the entrance, and 24 feet at ebb at the mooring places. The Nieuwediep only lacked the required depth. On 6 and 27 August 1781 a Commission was then mandated and ordered to execute this plan.
Constructing the harbor
On 5 September 1781 orders were given to create a stone dam east of the Nieuwdiep that would guide the ebb flow for 348,500 guilders. It was to be built in three parts (cf the map) The first part, the 'big stone and wood dam' () was 475 meters long. The second part, a slate dam, , was 655 m long. The third part, , stretched east to catch the ebb flow and was 2260 m long. The second part was ready on schedule in June 1782. The delivery of the other parts was delayed by the difficulties in shipping the heavy stones required. In October 1782 the third part was finished, the first part following a few weeks later. Nevertheless, the first effects were shown when in August 1782 the bump in the mouth of the Nieuwediep was found to have been lowered by 1–1.5 feet. In October 1782 orders were then given to dredge out a way through the bump by December 1782. This became March 1783, but in April the depth had indeed reached over 19 feet, and some armed warships had already anchored in the harbor.
In June 1783 33,000 guilders were spent for a dam, , of 500 m stretching SSW from the southern entrance of the Nieuwediep, creating a funnel together with part 3. To facilitate ships, 8,800 guilders were spent on 7 dolphins (cf map). 58,000 guilders was reserved for further dredging, that (after delays) would be executed in 1784.
For big warships the depth was still not enough. Therefore, in 1785 the third part of the eastern dam was prolonged by 750 m, and then by another piece of 376 m stretching to the southwest. In 1785 the ships of the line wintered in Nieuwediep. Still, Nieuwediep was nothing more than a harbor. It lacked facilities like stores and repair shops, which would make it a real naval base.