Willemsoord Dry Dock I is a historic dry dock in Willemsoord, Den Helder, Netherlands. It was constructed from 1813 till 1822, under the direction of Jan Blanken, and was part of the former Rijkswerf Willemsoord.
Context
Nieuwediep In 1781-1785 the harbor of Nieuwediep was created just east of Den Helder. It was meant for heavy warships, which had trouble reaching their home towns on the Zuiderzee. These home towns (like Amsterdam) vehemently opposed the construction of a competing harbor, and wanted Nieuwediep's function to remain strictly limited to harboring heavy warships. Nevertheless, from 1792 onward, some field fortifications were made to protect the harbor. A careening facility called or was also created. Here ships could enter at high tide, be put on their side at low tide and careen while a lock door prevented the flood from returning. The 1799 the Anglo-Russian invasion of Holland led to the capture of the base at Nieuwediep and the surrender of the cornered Dutch fleet in the Vlieter incident.
Naval base Willemsoord In 1811 Napoleon visited Nieuwediep and ordered the construction of a large well-fortified navy base. The fortifications would center on Den Helder, giving rise to the town of that name. The new navy base would be east of Den Helder, on the west side of the Nieuwediep, north of the Nieuwe Werk. The new navy base would later become known as Willemsoord, or Rijkswerf Willemsoord. Napoleon gave the order to design the new base to Jan Blanken. He was an engineer who had proved very effective in improving the navy base at Hellevoetsluis, and in designing the Hellevoetsluis Dry Dock.
Jan Blanken's design included a sea lock, a wet dock and a dry dock. The sea lock closed the wet dock from the tides. The wet dock provided safe anchorage, but its prime benefit was that ships stayed at the same height to the quays. They could also be brought in closer. It all led to easier handling and storage of ships. A dry dock was a facility that had recently become a necessity for any serious naval base. Heavy warships had become longer, and therefore more susceptible to damage from careening. Meanwhile, the problematic supply of good Scandinavian oak, and the practice of copper sheathing ships, had increased the demand for frequent below water maintenance.
Construction History
Foundations for the pumphouse
In 1813 construction of the pump building started with digging a pit for its foundation. Soon, quicksand and water seemed to have joined forces to prevent construction. However, perseverance prevailed and digging reached the required depth. Thirty piles were then driven into the ground, and work for that year was finished.
After the liberation, work on the pumphouse foundation was picked up again in 1816. The pit was pumped dry, and dug out again. However, the piles were nowhere to be found. They could neither be dug up, nor could they be found by exploring with iron sounding devices called s. The pit was kept dry by using three chain pumps, working round the clock. Suddenly, a well of 1 m diameter burst open. It filled the pit so quickly that the drivers of the horses that drove the chain mills had to cut the horses loose in order to save them. Jan Blanken was then Inspector-General of Rijkswaterstaat. He was assisted by the engineers Glimmerveen, Van Asperen and Wellenberg, and the later chief-engineer A. Greve, as well as the contractors Den Stok and Verschuur. They decided to continue construction at the same location, instead of changing the plans. After a lot of pumping, the well became visible. It continued to expel shells and water, and when a 36 feet pile was driven into it, it was launched like an arrow.
The well was stopped by layers of horse manure, rubble and other objects. Of course this was a stop gap measure, but at least the pit could be kept dry. The idea of pile driving was abandoned. Heavy fir beams were now laid down about 80 cm apart. The openings were closed by brickwork. Across this layer, a new layer of heavy fir beams was laid down, and closed by bricks. Any resulting depressions were again levelled by brickwork, and so a level foundation for the pumphouse was created.
Foundations of the dry dock
In April 1817, digging the pit for the dry dock was tendered together with digging a stretch of the wet dock from the sea lock to the dry dock. The order also included delivery of 5,000 oak and other piles, as well as 30,000 feet of related planks. The circumstances in the dock proved even worse than below the pump building. Three chain pumps worked day and night against a sea of sand, and 30 very pricey work horses worked themselves to death in spite of heavy feeding. The area was so wet and sandy that the sides of the pit were level like beaches. In spite of this, pile driving succeeded, and with enormous difficulties, connecting beams were attached to form the floor. It had to be levelled by hacking and filling up. The big plus of finishing this floor was that the quicksand was stopped from coming up.
Brick work of the dry dock The dry dock itself was made of brick with stone details. In April 1817 6,124 cubic feet of Petit Granit from Écaussinnes (blue stone) was ordered for the dry dock and the sea lock combined. In September 1819 and October 1820 it was noted that foundation planks and brickwork at the lower levels of the dock had been pushed upwards. As a counter measure 300 (probably 600 ton) of iron ballast was placed on top of these. In between these events, on 12 May 1820, the further works and completion of the brick side walls of the dry dock were tendered. In July 1822 the dock was dry, and 23 feet below high tide workers were making the blocks and other facilities to receive ships.
Pumphouse and Steam Engine
The pumphouse, later known as Steam Engine Building I, was built just west of the dry dock. It housed the steam engine and pumps, and was designed by Jan Blanken in neo-classical style. Its steam would drive 9 cylindrical pumps to quickly empty dry dock I. A subterraneous sewer connected the building to the dry dock. As the name implies this sewer was in the center line, just below dock, making that all water flowed into this sewer.
In April 1817 the rest of the pump building, and foundation for, and completion of brick sewers towards the still to be made dry dock was tendered. The building was finished by late September 1818.
The first steam engine of the dry dock was made by Dieudonné Forir in Liège. It would soon prove a failure. In 1822 the machine was inspected by Watt, but when it was found not worthy of repair, Boulton and Watt delivered a new engine in 1823.
Ship Caisson The dry dock was closed by a ship caisson. This had been built at Rijkswerf Medemblik. After launch it had been transported on ship camels to the Vlieter in 8 days. From there it was towed to Nieuwediep by two tugs, and arrived there on 29 June 1822. On 6 July the floating door was put in place in the dry dock, and was shown to fit very well. The door was later replaced.
First Service (1822-1849)
First use
On 13 July 1822 the ship of the line Willem I (formerly Couronne) of 74 guns was successfully placed in the dry dock. After the water was pumped out, the Willem I stood on the bottom of the dock with all its weight. Authorities were very pleased that they had now proven that the foundation could withstand the weight concentrated in the keel, and did not rift and become leaky because of pressures like had happened in France and in England in such situations.
These early reports would later prove to be way too optimistic. Already in 1821 it was noted that lower terraces and foundations were getting pushed up. Furthermore, it was noted that when the dock was empty, it rose and fell with the tide. The obvious conclusion was that the well was still working, and was connected to the sea. The power of the water was so strong that, while Willem I was in the dock, the floor was lifted 8 cm, proving that her weight did not make any difference.
Investigation and plans to solve the problem
In 1826 a commission under J. Blanken, including Captain-lt N.A. de Vries, naval constructor P. Schuyt, and deputy-constructor J. Landstraat made a report. They noted that in 5 years of operation, 6 warships had used the dry dock, and that its situation had not degraded. Furthermore, that as long a ship was in the dock, or it was filled with water of at least 2.51 m - 2.83 m high, there was no problem. However, when the dock was emptied, the well below the surface started to push up the dock for 9.4 cm, at the place where the mizzen-mast of a docking ship would be. (Note that the weight of the water in the dock, or a docking ship thus tended to keep the floor in place.)
The 1826 commission obviously found the problem serious enough. It the proposed to fix the problem by laying 26 oak beams of 52 and 63 cm diameter on the floor of the dock, perpendicular to its length. These would have to be clamped to the foundation planks by iron braces, and to be connected to each other below the brickwork. These beams would then have to be walled up with brick, and an oak plank floor laid over these. The cost of these repairs was estimated at 59,297 guilders (see Fig. 1).
In June 1827 the repair job was offered to contractor A. Korf in Den Helder. He demanded 129,642 guilders to do the work, and made other demands that led to the job getting postponed. In 1829 a totally different plan was made chief engineer D. Mentz. It proposed to break out the part of the dry dock between the walls, and then to build a brick inverted arc in the dry dock for an estimated 355,000 guilders (see 1828 drawing). In April 1830 the government decided to execute the Mentz plan in 1832. By December 1830 the estimate had increased to 399,949 guilders.
By 1832 the Dutch financial situation had become so desperate that the Mentz plan came to nothing. Actually nothing would be done till 1853. What was done, was that the ballast placed inside the dock was steadily increased to 653 last of iron (see Fig. 1).
Regular operation In spite of leakages, Dry Dock I continued in use till 1849. From 1822 till 1849, it served without interruption, docking 120 ships in 27 years. In September 1848 the frigates HNLMS Prins van Oranje (60) and Sambre (44) were serviced in 5 days, with their full armament on board.
During investigations in 1849 and 1857 no traces or repairs were found, and so one could assume that not much was, or had to be, spent on maintenance.
The dock is shut down (1849) The caisson door lock of the dry dock was first to show serious trouble. In 1838 it had been so much deformed, that the ship caisson did not fit anymore. The old ship caisson was then stored in the dock, and a new ship caisson that fit the deformed lock was made. This new caisson had the serious disadvantage that it could not be turned around for cleaning and maintenance.
In April 1849, the razeed frigate Algiers was in dock, when so much water passed the door, that the dock could not be made dry again. This put an end to the service of the dock.
Failed repair, investigation and Rebuild (1850-1861)
Failed attempt to repair the caisson lock After the dock had become unserviceable, the naval minister requested to increase the 1849 navy budget by 20,000 guilders, so the problem could be investigated. In 1850 a dam was constructed in the wet dock for 18,827 guilders. In 1851 a budget law for 155,000 to rebuild the lock was defeated, but in 1852 the sum was granted. In 1853 and 1854 the lock of the dry dock was then rebuild for 177,366 guilders. Observations during the repairs looked very positive. When the rebuild of the lock was finished, the dam was removed, and the ship caisson put in place. However, when the pumps were started, it proved impossible to empty the dry dock further than 3.5 m below sea level.