Tide machines

 Just one image among many on the Internet, of a tide machine, together with Arthur Doodson, who used such tide engines to profile the tides at Normandy for D-Day.  

 

This article, from the shipyard blog, about the tide predictions for D-Day, presents high quality images of several versions of tide machine, and an excellent story.

The Battle of Tarawa, however, in The Gilbert Islands, is an example of tide predictions gone wrong.