Locks are how boats go around waterfalls and rapids, and dams. Locks are probably the oldest technology we dealt with on our Viking River Cruise. They still work the way they did in the 14th century (in China, in the 11th century).
You have a chamber with a heavy gate at each end. The water height at the 2 ends can differ by a couple of feet, or several tens of feet. Your boat enters the gate at its water level; the gate closes; the lock keeper opens valves that let water pour in, or out, depending. You sit there while the lock chamber fills, or empties. When it matches the new water level, the other gate opens and you move on. The water is entirely moved by gravity; there are no pumps.
Some locks can take several boats at once; some locks are so small they can only take one; and they all handle traffic going both upstream and downstream. We had at least one major delay where the Embla was in a line behind several other boats at a small lock, and another where a boat got stuck in a lock. There’s a lot of boat traffic on the Rhine-Main-Danube route, including cargo haulers, and it all goes through those locks. The Embla barely fit in some small locks – I can remember standing on the side balcony and reaching out to touch the lock wall with my hand.
There was some confusion over how many locks we went through. My original notes say 68, and I’m not sure where I got that. I Googled the question “how many locks are between Amsterdam and Budapest” and came up with an estimate, from a site on river cruises:
- From Amsterdam to the Rhine, 1
- On the Rhine itself, 12
- On the Main, 34
- On the Rhine-Main-Donau canal, 16
- On the Danube, 16 that we went through (there are more downstream from Budapest)
That comes to 79 locks!
