How are tide tables made?
Wow, very interesting question… Apparently it isn’t easy, since the United Kingdom doesn’t give its tide information away, and has upset quite a few people in an attempt to defray the cost of gathering and publishing the data. I gathered in my research that it takes the combination of algorithms, measurements and statistical analysis (to verify the former against the latter) to generate truly accurate and useful tide tables. They are genereated by lots of governments and institutions, and some are better than others. One freeware program (that excludes the British Isles, of course) says it has info for 9,500 sites around the world, but you shouldn’t “bet your life” on the data. It turns out that tides are periodic, but chaotic, as are many natural phenomena, and require constant monitoring and adjustment, analogous to predicting the weather. The freeware site is: http://www.wxtide32.