How do I get an over lay of tides in an area
You can activate the tide forecasts at the right hand bottom of the website page (the last icon on the icon bar, next to the webcam icon).
By activate it, you will experience that it will appears at some coastlines, unfortunately there are no tide indication data for all the shores.
You can find tide forecasts in North-West of Europe, in the USA coatlines up to Canada, in Central America (such as Mexico, The Bahamas, Cuba, Dominican Republic, Guatemala, Nicaragua), in the East Coast of South America, in Japan, in Australia, in Papua New Guinea, in Solomon Islands, in New Zealand and some other little islands.
Some examples by screenshots:
(the little yellow points at coastlines indicates the tide forecasts)