Lauenburg: Die Palmschleuse

It is the oldest chamber lock (boiler lock) in Europe.The Palm Lock was built in 1398 throughout the Stecknitz Canal entirely of wood and was one of 15 locks this first watershed channel in the world (construction period 1392-1398). Since the Middle Ages, the lock was also known under the name Schlüse zu Bockhorst. As a chamber lock she was documented since 1480.In the 17th century, it got its present name after the then lockkeeper Palm. 1724 was carried out by order of George I of Great Britain, the expansion of the lock, this was bricked out with hewn stone. A coat of arms in the lock wall reminds of this expansion.The lock remained in operation until September 1, 1896. In 1962, the Palm Lock was restored in the course of the ditching of the Stecknitz estuary.Source:
de.wikipedia.org/wiki/Palmschleuse

The Palm Lock at Lauenburg is one of the few preserved early chamber locks in Europe. It belonged to the lock system of the medieval Stecknitz Delvenau Canal, which connected the Elbe with Lübeck. It was the first true watershed canal in Europe and once world famous. This canal was built in the years 1390 to 1398 by the Lübeckers in agreement with the Duchy of Lauenburg.Between the north to the Trave flowing Stecknitz and the south to the Elbe flowing Delvenau was a 10 km wide, glacial ridge, which had to be pierced. To overcome the considerable height difference 17 locks were necessary. Initially, they were only simple, closed on one side lock catches, in which the water was dammed up until this congestion was strong enough to carry the waiting ships after opening of the shooters to the next lock. This could happen only every second day, the tap day. For example, the 93 km long canal journey took about three to four weeks. Upstream had to be made. Nevertheless, the water transport was more economical than on land, since the canal ships could take after 10 to 15 wagon loads.
The conversion of some lockers to both sides closed chamber locks made the canal way faster, because it was possible to pass the economical water consumption faster. However, the wooden locks soon fell into disrepair. Only the Lauenburger Palmschleuse, which received its name from the former lock master around 1600, was completely renewed in 1724 and provided with stone borders. As a reminder, the coat of arms of Lübeck (double eagle) and the Electorate of Hanover (coat of arms) have been walled opposite each other. Lauenburg belonged to Hanover after the extinction of the old family of herd.
herzogtum-lauenburg.de/a-palmschleuse

Great historic palm lock. You don't see that often anymore. The lock remained in operation until September 1, 1896. In 1962 the palm lock was restored in the course of the dike in the Stecknitz estuary.