Locks were a regular feature on our journey along the Danube. Though contributing to the slowness of river traffic (particularly relevant to commercial traffic), they always attract great interest on the tourist vessels, with many passengers out on the upper deck to get the best views & photographs.

Many of the tourist ships (a more common title on board than "boats") are built to a width, just & only just, allowing the vessel to fit into the lock. Bumps on the side are not unusual, there being only a few centimetres to play with.

Note the depth of the lock pictured above; some are somewhat less deep..   The rising or falling of the vessel can take some time to carry out. However, as the location & depths of every lock are well-known to the senior crew members of every vessel, schedules still remain unpredictable because of traffic volumes. It is always possible to approach a lock & find several other vessels queuing up to go through. Very long waits can occur on sections of the Rhine, though much less so on the Danube.