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Tidal Current Charts
The online software WWW Tdie and Current Predictor has helped me somewhat. Current speed is not available for most locations, but I was able to get data at Boston Light. The good thing, though, is that you can get tabulated or graphical output for any time between 1970 and 2025 AD. You are not limited to the present day analysis like the other sites give you.
It looks like the seasonal max flood is around 1.5 kts. Do you think I can get a good estimate of the current speed between 1775 Boston and Charlestown from simple geometry? If I assume same depths, and compare the mouth of the river at Boston harbor (width D) with the size with the necked-down area (width d), then conservation of mass should give me a good guess. Then neglecting changes in salinity, v = 1.5kts x D/d. From old maps, I estimate D/d to be 8/5. This give 2.4 kts ceter channel speed. From a mariner''s practical experience, does this make sense? Or did I over(under) compensate?
Finally, though I have data I can work with, I still want a chart with the current depicted on it like the one that appears in the article mentioned at the befinning of this thread.