By Tony Johnson
Learn to use the current mini-charts in the back of your tide book to plan your day. They display the behavior of the currents in the Bay for every hour of the tidal cycle. The instructions on page 48 give you the procedure to adjust the figures on the charts to get accurate readings, but here’s a shortcut: If Max Flood at the Golden Gate is about 3.3 knots, or Max Ebb is about 4.5, the numbers in the arrows are correct. If the figures at the Golden Gate are higher, the figures in the arrows will be higher up to 50% at most. If they are lower, the figures in the arrows will be lower. But even if you don’t bother with all the multipliers, the charts give you a quick graphic perspective on what currents to expect during your sail.
Good advice. I use the current charts in the back of the tide book every sail. I carry a pocket note/log book and write down, in order, the sequence of tidal events on the days I sail so it is easy to find the correct chart. High tide – slack – max ebb – low tide – slack – max flood – etc. It not only helps when traveling outside Golden Gate or to Vallejo but using currents can increase boat speed more than that last refinement of sail trim. Knowing the general current flow can also help you decide which side of that buoy in your path you should plan to pass on. In my experience, trying to slide by on the “upstream” side usually results in some kind of last minute maneuvering.