[AugustH]

As for the AyeTides, I don't think I should pay twice for information I have already purchased with the Navionics chart. Also, I suspect that AyeTides uses publicly available harmonics databases, whereas the Navionics chart containg national hydrographic data and is capable of showing current info for europe as well as the Americas

For AyeTides I do use publicly available harmonics but I also go out and find tide gauge data for locations around the world, and analyze the data to create harmonics. I have more locations, and more accurate results, by using the tide data. As for currents in Europe, I have a web page at http://www.ayetides.com that explains why I don't have those kinds of stations - in short, the predictions come either from hydrodynamic models that are impossible to port to a phone, or they come from a gov't body measuring, for a very limited time, the currents at a location and then correlating the currents to a nearby tide location. The accuracy of the latter approach is not very high, as it can estimate only 2 harmonics out of the hundreds that are measurable. The Navionics app uses the time offset from the tide station method, and it shows a very disjointed series of line segments for a current station off England. You don't see slack times at all! (the image is on the web page).

I'm not sure why people are so hyped about currents in Europe when the predictions don't seem to be reliable.