Max Ebb — Tides and Details
No question about it, young techies are the best navigators. They know how to extract the latest weather info from the Web, and they can make Expedition dance.
But when my favorite geeky grad student, Lee Helm, is not available, I might have to cast one of my contemporaries as tactician.
“Tide book is loaded!” he announced as he stepped aboard and handed me the little tide book. “Check out the ebb we have today.”
We had been sailing together since we were both in child-size PFDs and El Toros, and we learned to race in those ancient times, back when the best tidal current data could be found in that little book that most marina offices sell for about a dollar. We had both developed similar protocols for preparing the book for a race. Each page of current diagrams was marked up as follows:
1) Cross out the pages for the Carquinez Strait (unless this is for a Vallejo race.)
2) On the tidal-current table page for the date of interest, underline the row of data for the day.
3) On the current-diagram pages for max flood and max ebb, write the times of max flood or ebb in the inset for Treasure Island.
4) Look up the strength of max flood and max ebb, then consult the table that gives the ratio of the predicted current speed to the speed of the spring tides shown in the diagram. Write this velocity-correction factor in the remaining space in the Treasure Island inset, below the time of maximum current.
5) Write the applicable times on the tidal current diagram pages for one and two hours before max flood or ebb, and one, two, and three hours after max flood or ebb. Now every page has a time stamp and a speed correction factor.
6) Add the predicted time of the next slack current, taken from the current tables, to the bottom margin of each page. Add the predicted time of the previous slack current to the top margin of each page.
“Good work,” I acknowledged my friend’s effort. But he was about to be upstaged by the next crew to arrive: an undergrad engineering student, recommended very highly by Lee Helm.
“He’s just starting to learn to sail,” she had told me. “But I think he has, like, the right mindset for navigation and tactics, once he learns the strings.”
Not surprisingly, considering Lee Helm’s assessment, he did not bring a marked-up tide book. He carried a loose-leaf binder with the Sailing Instructions and Course Sheets in plastic sheet protectors.