Zenith naval clock/timer??

It's a vintage tachograph. Case opens and a paper disc is mounted inside to record revolutions/speed/time. Probably used on European canal barges.

Here's one seen earlier, probably used for the same purpose on the ships on the American Great Lakes and canals where shipping was quite regulated.

(scroll down a bit)
https://omegaforums.net/threads/the-aviators-thread.135513/page-55#post-2149886

As noted by @Omegafanman:
"The German clock is a tachograph which will stamp a card and click on a red indicator at the end of a period."

They were also used in trucks/busses/aircraft, in fact anywhere an employer wanted to know that the driver/skipper/pilot wasn't thrashing their equipment, wasn't exceeding operating hours etc.