A pair of San Francisco State University researchers has developed a free app called “Bay Currents,” available now through the Apple app store.
According to to their publicist, “Bay Currents uses real-time information from land-based sensors along the coast and San Francisco Bay to give sailors a look at present current conditions, the previous 24 hours of currents and a projection for the next two hours. Users can locate their position on the water using GPS technology or place pins at points in the Bay to get an understanding of currents at that location.”
I downloaded and it looks cool but as I don’t sail out West I have no idea if it provides useful and accurate info.
You can learn more here.