On Monday afternoon, March 31, 2025, 3 yachts will be passed through the blocked chamber of the Princess Máxima Locks at Lith. Rijkswaterstaat, together with the contractor combination Mourik Swarco (CMD), explored the possibility for this. With the help of a temporary construction, this passage can be organized.
Economic Importance
Since the beginning of the blockage, which has been ongoing since February 18, we have been in contact with various stakeholders. One of them, Heesen Yachts, indicated that there was a significant economic interest in exploring whether it would still be possible to pass 3 yachts at once.
The yachts are too tall to be passed through the south chamber, where a maximum height of 7.10 m applies. Circumnavigating is also not an option due to the height. The importance was recognized by us, and together with the contractor combination Mourik Swarco (CMD), we explored if and how this could be made possible.
Doors Removed
On February 18, the doors of the north lock, on the Lith side, were damaged in a collision. On March 5, these doors were removed from the lock by the contractor combination Mourik Swarco and taken away for further investigation. This means that the lock on the downstream side (the Lith side) no longer has doors and the lock is blocked.
Alternative Doors
To pass a ship, both sides of the lock must be closed. This is necessary to regulate the water level in the lock. The shipping must also be able to sail in and out of the lock. During normal use, this is done via lock doors. Now that the lock doors on one side of the lock have been removed, this is solved by, simply put, placing large steel bulkheads across the entire width of the lock in that lock.
Since these bulkheads cannot move like lock doors, we have to lift them in and out. We do this with a floating crane (a derrick). CMD has modified these existing bulkheads so that we can safely close the chamber on the Lith side and adjust the water level in the lock.
Method
The yachts come from the upstream side (the Alphen side) to the lock. We ensure that the water in the chamber is as high as on the upstream side of the lock. This is done using the bulkheads.
When the yachts are in the lock, the doors at the top also close. Then we lower the water in the chamber so that it is as high as on the downstream side (the Lith side) of the chamber. Then the bulkheads are removed, and the yachts can sail out.
Normally, we regulate the water level via slides in the doors, but they are not there now. Now we make a kind of mailbox in the bulkheads so that the water can flow out of the chamber and the water level drops. Once the water level is equal to the level on the Lith side, the bulkheads can be removed, and the yachts can proceed.
Unique Method
The bulkheads used are not intended to be used as doors. By modifying the resources themselves, taking various safety measures, and the necessary preparation time, it was possible to deploy this method of passing on March 31, 2025.
The yachts will remain moored for one night, and 2 of them will continue their journey the next morning.