Thread: The Doodson-Légé Tide Predicting Machine

Hi Ewan

I watched that show . Yes what a mechanical marvel

They praised nylon but omitted to say that the worlds oceans are now plagued by bits of the stuff that will take centuries to break down .

The little horse drawn Victorian bathing boxes for women were rather novel

Thanks for posting that, a truly amazing bit of engineeering

The most complex real time software I ever wrote had zero inputs and only 1 output. It was to disable/enable a pump system based on tidal caclulations.

The algorithm was basically a calculation based on a large number of sine waves, with different phases and phaseoffsets.... , a little bit like a fourier series with some feedback components If I recall correctly, Just looking at the mechanicals I wonder if it's a mechanical implementation of the same algorithm?

I wish I could remember where the algorithm came from..

Regards
Ray

Hi Ewan,

Well there you go, it was using the Doodson Harmonic Analysis stuff after all...

Here is a link to the book...
http://archive.org/details/philtrans08044568

Regards
Ray

Thanks Ray, I just downloaded the book. I can't promise that I will read it (or possibly understand it) but I once wrote software to control an outfall valve (2 km out to sea) dependant on the tides.
It needed the tide tables downloaded from the maritime website and uploaded to the PLC every 3 months or maybe 6 months, I can't remember. A tide predicting algorithm would have been much better.