[Jeroen]

Where would you find the largest Sea lock in the world I hear you ask? Why, in the Netherlands of course!

In an ideal world large international harbours are open to the sea/ocean. But its not always possible so it will require some elaborate locks.

I visited the new Zeesluis (Sea Lock) in IJmuiden, the Netherlands recently. It is the entrance to the Noordzeekanaal (North Sea Channel), connecting IJmuiden with the port of Amsterdam.

I am pretty familiar with the locks in IJmuiden. I passed the locks on an LNG tanker whilst 12 years old. The owners were a client of my dad, who allowed me and a friend of mine to come along for a couple of days. Our parents delivered us aboard somewhere in the Amsterdam harbour. The ship called the Athina, cast off and made its way through what was then, till recently, the largest lock in IJmuiden. (And also the largest sea lock for decades). We sailed across to Immingham, UK, next to Esbjerg in Denmark. My dad drove over and picked us up again. Quite the adventure for two 12-year-old boys amidst a Scandinavian crew who did not speak Dutch and we hardly spoke English.

This must have been early 1970s. About 6-7 years later I was at the Naval College of Marine Engineering. As a job during the holidays, I worked as a deckhand on this harbour tug.



These tugs would pick up the vessel in the sea lock and escort it all the way to the Amsterdam harbour area or vice versa. Amazingly, this very tug is still in use. It looks a little different but not by much. My son Luc and I came across it working in the Rotterdam area last year when we were our on our yacht Sirion.

https://www.team-bhp.com/forum/comme...ml#post5807154 (Bought a Yacht | 2006 Drammer 935 Classic)

My dad was a lawyer and he specialised in maritime and international transport law. So he was often called in to deal with accidents with vessels and or their cargo. One of these accidents was on the old sea lock. I was about 19-12 at the time, so late 70s. I heard of an accident in the seal lock. I happened to be near so I drove over. The KNSM vessel Breda had managed to ram itself and its bulbous bow into the outer lock door.

Here you see the Breda still in the lock.



Does that look like the finger print of a bulbous bow into a lock door or what?



Recently on a Facebook group about "old merchant navy ship" I met somebody who was onboard and told me the story how it all happened. It doesn't bear revealing in public. It was also a different story from what the official report read like.

I have visited the locks many times over the years. I was there when the famous Dutch towage and salvage company towed MS Herald of Free Enterprise into the locks. She capsized as she left the port of Zeebrugge because the crew had not closed the bow door properly. 193 people died that evening.

https://en.wikipedia.org/wiki/MS_Her...ree_Enterprise

In those days, the general public could just walk freely all over the lock. I stood there, captivated by this salvaged wreck.

Anyway, so fair to say, I have somewhat of a history with the locks in IJmuiden.

I knew a new lock had been built, I had even been to see it. But when I saw an invite on Facebook to participate in a proper tour of the locks, I jumped onto the opportunity. The tour was organised by the IJmuider Zee- en Havenmuseum. (https://www.zeehavenmuseum.nl) A very nice little museum, but crammed with interesting stuff. The tour would start here with a presentation, followed by a little tour over the lock. Our guide was Hans. When I say we, it was actually only me that showed up. All other participants cancelled, we have a bit of a flu epidemic going on, and some just did not show up. Hans told me, well, you showed up, on time and all, so let's get going.

The museum has also given me some of the images from Hans his presentation. Many thanks!

Just a little bit of history on Amsterdam and the North Sea Channel. (Mostly borrow from Wikipedia)

The North Sea Canal (Dutch: Noordzeekanaal) is a Dutch ship canal from Amsterdam to the North Sea at IJmuiden, constructed between 1865 and 1876 to enable seafaring vessels to reach the port of Amsterdam. This man-made channel terminates at Amsterdam in the closed-off IJ Bay, which in turn connects to the Amsterdam-Rhine Canal.

The drainage of the canal to the North Sea is done through the IJmuiden sea lock, augmented by the largest pumping station in Europe. This system is vital to the groundwater management of the Western Netherlands.

To improve the connection between the harbour of Amsterdam and the North Sea, the North Holland Canal was built in 1824. But this long and narrow canal was quickly inadequate to handle the growing boat traffic. A few decades later, it was decided to dig a new canal at the narrowest point in Holland, thereby providing the shortest route to the sea.

Digging began on 8 March 1865, at the dunes of Breesaap and lasted until 1876. Since no Dutch company was willing to take on this task, the project was awarded to an English contractor.[citation needed]

The North Sea Canal was built by digging a channel through the old IJ Bay and lining it with dikes, after which the remaining portions of the IJ Bay were reclaimed and turned into polders. From this bay to the sea, a new canal was dug through the dunes at Velsen. To accommodate drainage of and shipping on the tributaries of the IJ, such as the Spaarne, the Zaan, and the Nauerna Canal, nine auxiliary canals needed to be dug as well .

A small set of locks (Zuidersluis) were built at the mouth in 1876 where the new town of IJmuiden (Dutch for "IJ Mouth") formed. In 1896 the Middle Locks (Middensluis) were built, followed by the North Locks (Noordersluis) in 1929, which were Europe's largest locks at that time.

At the eastern end of the canal, east of Amsterdam, the IJ Bay was open to the Zuiderzee until 1872 when the Oranje Locks (Oranjesluizen) were built. With the completion of these locks, the North Sea Canal and IJ Bay were no longer open to the sea and a specific water level could be maintained.

The canal was dug using manual labour. The workers lived in horrid conditions, being housed in huts built from twigs, driftwood, sod, and straw, where disease, fights, and alcohol abuse were rampant.

On 1 November 1876, the North Sea Canal was officially opened by King William III of the Netherlands. Over the years the canal has been widened and deepened several times.

Hans also told the story as I found it on Wikipedia. At the time, there was nobody in the Netherlands who dared to be responsible for breaching the dunes for a channel. Those dunes are very very precious to the Dutch. They prevent the Netherlands from flooding from the high seas. So they brought in an English Contractor.

Another fascinating fact Hans told me: Look at this map, why was the channel not built more or less straight in an East to West orientation? In those days IJmuiden did not really exist? Why does it have this peculiar Z shape?



Look at the map, the area south of IJmuiden, e.g. Santpoort, Bloemendaal was full of homely estates from the rich traders of Amsterdam. They were the ones that pestered the King to build the North Sea Channel, but of course, the channel had to built around their fancy estates!!

Ships have become bigger and wider in recent decades. Modern ships carry more goods and bulk. And there are also larger cruise ships. In order to continue to allow these ships safe and smooth access to the Port of Amsterdam at low tide, a larger sea lock had to be built at IJmuiden. In 2016, work therefore started on the lock complex. The new sea lock was scheduled to be taken into use in 2022. A little bit more about this date later.

It was a very tricky project, because the nieuwe Zeesluis had to built right next to the old one.

Here you have two images showing before and after the new Zeesluis was built.
the red rectangle is where the new Zeesluis was going to be built.



This is what it looks like today.



You will have gathered by now that there are several locks in IJmuiden. This is a good overview. Sorry all in Dutch but the translation is pretty easy, from left to right:

kleine- zuidersluis: Small and Southern locks. These were the original locks. Nowadays primarily used for recreational vessels, small barges, the odd tugboat and so on.

Middensluis: Middle Lock. A sizeable lock in its own right. It could accommodate a vessel up to 200 meters in length. However, due to the new Zeesluis vessels leaving the middle lock, they need to make a turn and the maximum ship length that is allowed through the middle lock has somewhat been reduced. I have some images that hopefully illustrate the issue here.

Noordersluit: Northern lock. Until recently, the largest lock

Zeesluis: Sea lock. The new largest Sea lock in the world!!

Spuisluis: Purge sluice (not quite sure on the translation). I will come back to this one, as it plays a hugely important role in how we keep the saltwater out of the North Sea channel.



Hans spoke extensively about the design and building of the lock. I always find these huge infrastructure projects fascinating. Unfortunately, I do not have images about the building, nor have I been able to find any English Youtube videos. Plenty of Dutch Videos out there.

These sort of projects are commissioned by what we call Rijkswaterstaat. Part of the ministry of infrastructure and water management. A Dutch national governmental body that looks after all Dutch rivers, canals, coastal defense, pumping stations and so on, including our highways and provincial roads.

They contracted the design, building and the first 26 years of maintenance, including all financing, to a consortium called OpenIJ.

So how big is this new Sea Lock? Pretty BIG!

It is 500 meters long, 70 meters wide, and its depth is 18 meters. It has three lock doors as you will see in my images. One is a spare lock door, which could replace the outer or inner doors. These doors themselves are huge of course, as you will see and are a marvel of engineering themselves.

After the presentation, Hans and I got in our cars and made our way to the lock complex. Before the start of the building of the new lock, you could drive your car across the lock complex. Although there is a road, vehicle traffic is blocked off. You can only pass by foot or by bicycle, or moped.

Just for a small "Indian" connection. North West of the IJmuiden lock complex are the Dutch Hoogovens, the Dutch Steelworks. We still call them, but they are owned by Tata. The Dutch and in particular the people living nearby have a lover/hate relationship with the Steelworks. It has provided lots of jobs for many generations, but it is also a terrible polluter!



This is the outer entrance to the Sea Lock. The door is closed. It is difficult to get a sense of scale here, but the width of the lock is 70 meters!



This is that same door. You get a better sense of scale here. A complete wide road on top of it!



I noticed these peculiar red lines. Hans explained: a while ago there was a demonstration by Extinction Rebellion on the sea lock to prevent a Disney Cruise ship from entering. (https://nltimes.nl/2024/08/18/extinc...ships-ijmuiden)

They put these red lines on the door locks as part of tightening up the formal laws and regulations on where people can stand and so on afterward. Not sure if the good folks of Extinction Rebellion will be impressed though, let alone intimidated by some red stripes.



And here you see the actual inside of the lock. Unfortunately no ships when we were present!



Taken from the middle of the outer door: This lock is massive!!



Although its 18 meters deep, the maximum draft of vessels going to Amsterdam harbour is less. About a kilometer east of the lock is the Velzer tunnel. It allows one of the main motorways towards the North to dip under the North Sea Channel. But that tunnel is at approximately 16 meters and the maximum permissible draft is even less!

However, they decided on 18 meter depth in the lock to accommodate tidal and wind effect inside the lock with the doors open. A combination of specific wind direction/speed and low tide brings the water level in the lock down to the point where a certain vessel could not enter on low tide. So they decided for that reason alone, to lower the depth of the lock itself well beyond the maximum draft in the North Sea Channel.

If you have followed my thread on our yacht Sirion, you will have come across me talking about a lot of the bridges and locks being remotely operated all over the rivers and canals in the Netherlands. Not so with these locks. This is the control tower for the lock operations. All fully automated, one person is all it takes to push some buttons. Notice the peculiar slant of the building and windows? Apparently, that is so there are no reflections from the window toward the vessel's bridge and crew out of the bridge/bridge wings



On both ends of the lock there are these smaller cabins. The lock can be operated from either position.



Look at these markings inside the lock. Number 50 is the 500 meter mark.



The lock seen from the other side, so we are looking in a westerly direction towards the sea and the Dutch (Tata) Steelworks.



Now, coming back to this so called "Spuisluis" (purge sluice).

There is also a pumping station complex on the north side of the locks. Here, salt water will be returned to the sea by means of selective extraction. This is necessary because otherwise the water in the hinterland would become too salty. Every time a ship passes through the locks, salt water enters the canal. Too much salt water in the North Sea Canal has a negative impact on our drinking water, nature and agriculture. A kind of screen has been built at the beginning of the Binnenspuikanaal. Salt water is heavier than fresh water. By keeping an opening at the bottom of the screen, most of the salt water disappears, leaving fresh water behind.

Sorry, all in Dutch, but I trust you get the gist.



Here you see that pumping station in the far distance



And here you see that screen on the other side of the canal. The middle section has been lifted out, so ships can enter the canal for maintenance and so on.

[Jeroen]

Let's look at some more details of this immense sea lock.

As you enter the lock you will pass this sign. Not sure who put it up, to what purpose. I'm pretty sure any crew worth its salt (pardon the pun) will know in which lock they are? Maybe for the cruise passengers?



These huge locks always have these wooden rafts alongside the lock walls. They rise and fall with the water level, along chains, inside the lock, or the tide (these are the ones attached on the outside.

Very effective way of mooring a gigantic vessel gently against the lock wall.



In earlier images you might have noticed these little concrete "sheds" along both sides of the lock. These are to provide cover and safety for the linesman handling the vessel mooring lines. Occasionally a mooring line might snap and you don't want to be waiting around for that to happen. These lines men know instinctively when a line gets overstretched and will run for the nearest shed for cover.



A close up of this weird control tower. Remarkable building



This is the entrance to the control tower. It has a remembrance plaque attached to it, which reads: His Majesty Kind Willem Alexander of the Netherlands opened the Zeesluis on 26th of January 2022.



But a little less known: For the first couple of years, they hardly used the new Zeesluis. The reason the Spuisluis was not ready yet! And that meant too much seawater came into the North Sea Channel, turning it brackish. Which is a real issue. So they only used it occasionally until the Spuisluis was ready too.

Remarkably, it was a different company from OpenIJ who had been given the contract to design, build and maintain the Spuisluis.

I walked all the way to the inner lock door, which is also the location of the spare lock door as I mentioned earlier. The one at the front is the spare door.



Here you see both the spare door (left) and the actual inner door lock (right)



Here you can see the drive train mechanism of those doors. They pull themselves along using a sort of cog/teeth mechanism.



Close up


As I mentioned, you can'tdrive across all locks anymore. But you could still drive across the "kleine- and Zuidersluis and park your car there. I just happened to notice my Mini!



As I walked back to my Mini, I noticed a vessel started to enter the Midden (middle) Lock. So I took a few images as it entered the middle lock. Not as impressive as the very large Sea lock, but the best I could do that day.





See the linesmen?



Remember I spoke earlier about how the maximum length of ships passing through the middle lock had been reduced, due to the building of the new Sea Lock. Here you can see why. This image is taken standing in the middle of the inner door on the middle lock. On the left you see that "wall of concrete" curving inwards. So large ships need to take a starboard turn immediately when leaving the middle lock. For safety reasons, they reduced the maximum length.



Finally, the ship that passed through the middle lock on its way to Amsterdam harbour.



I had a very interesting afternoon. Learned a lot thanks to the very enthusiastic and knowledgeable guide Hans. Many thanks, and thanks to the museum for allowing me the use of some of their slides.

I also took the opportunity for a little reconnaissance trip in the area. This year will see Sail Amsterdam 2025. Sail Amsterdam is huge sailing event that draws a large fleet of traditional windjammers to Amsterdam. It also draws a lot of recreational boats. Including your truly. 2.3 million visitors in 5 days. More than 10000 boats!!

I went to see a nearby marina and spoke to the harbourmaster about getting a mooring for a couple of days. I plan to sail Sirion to Marina IJmond on Monday, the 18th of August. My eldest son Luc will join me on Tuesday 19th. Very early on Wednesday the 20th of August, my best friend Peter will join us too. Sirion will slip its moorings at 06.30 am and make its way to the Zeesluis. An 8 kilometer trip along the North Sea channel. Most likely hundreds if not thousands of other recreational boats will be about as well, making their way to the Sea lock. But we think we will have a head start on them. At around 09.30 the complete fleet will leave IJmuiden and start making its way towards Amsterdam harbour.

Have a look:

https://www.youtube.com/watch?v=GpFcxkBCkeM

It's going to be epic!!

Jeroen

[BlackPearl]

Thread moved out from the Assembly Line. Thanks for sharing!

[manonsong]

I don't think this is the largest sea lock, well maybe if you discount the Deurgandock Lock on the left bank of the Scheldt in the Port of Antwerp, which I think, is the largest lock in the world. It is on the river, so maybe Sealock may be a misnomer.

[Jeroen]

Originally Posted by manonsong

I dont think this is the largest sea lock well maaaybe if you discount the Deurgandock Lock on the left bank of the Scheldt in the Port of Antwerp. Which I think, is the largest lock in the world. It is on the river so maybe Sealock may be a misnomer.

The sealock in IJmuiden has the same length (500m) but it is 2 meters wider and 0.5 meter deeper. Until it formally opened in 2022 this Deugandock or Kieldrechtsluis as it is now known, was the largest lock. If you google “largest lock” google will still find this one.

But factually the Dutch Sealock is larger, not by much. But the Dutch would never let the Belgians get away with having the largest lock. The Belgians only had the record for 6 years.

Jeroen

[V.Narayan]

Thank you for such a marvellous thread on these marvels of civil & mechanical engineering. You always take great pains to explain everything with photos and drawings. These maritime thing always fascinate me.

[Kkumar]

Vow, what a fantastic article. Learned something new. I have seen many videos of locks in the Panama Canal, but this is the first time I have come to know about the intricacies of the working of a sea canal. Thank you for sharing and keep on munching miles.

[rst89]

Thanks for this thread.

Does the Dutch government monitor the salinity of water of the North Sea Channel? It's interesting to know how the salt water is thrown out but some proportion might still remain in the channel. And any effect of low/high tides?

I am also guessing Rotterdam port handles the bigger cargo ships while the AMS one handles small cargo.

[Jeroen]

Originally Posted by rst89

Thanks for this thread.

Does the Dutch government monitor the salinity of water of the North Sea Channel? It's interesting to know how the salt water is thrown out but some proportion might still remain in the channel. And any effect of low/high tides?

I am also guessing Rotterdam port handles the bigger cargo ships while the AMS one handles small cargo.

Yes, to the best of my knowledge salinity is measured everywhere in the Netherlands along all coastal water.

During low tide, water from the North sea channel is led out. Several other riverways end in and around Amsterdam harbour and thus to maintain correct levels the water is pumped out during high tide and flows out naturally during low tide through special sluice gates.

High tide brings in more seawater as the level in the lock will be higher.

Rotterdam can handles the largest vessels in the world. It can handle vessel with a draft of up to 23 meters. Recent research shows it could be a bit more even.

Ships well over 350 meters can be accommodated in the Amsterdam harbour, so not just small cargo. It has container, general cargo, bulk and cruise facilities. Its the 14th busiest harbour in Europe by tonnage!

I sailed from Amsterdam harbour to IJmuiden Sea Locks and back again last year on my yacht Sirion. These images will, give you some ideas on the size and type of vessels you will find in and around Amsterdam harbour.

https://www.team-bhp.com/forum/comme...ml#post5870539 (Bought a Yacht | 2006 Drammer 935 Classic)


Jeroen