Monday, November 21, 2016

Learning to go with the flow on San Francisco Bay

A gorgeous day on the bay proved to be just a  bonus for our paddling group  

A kayaking class on tides, currents and rough water….

…recently reminded me that I took up writing as a vocation because higher mathematics was a deep, dull subject to me. And by “higher mathematics,” I mean stuff that your average fifth grader can knock out between video games. Not me -- words be my thang.

Jennifer Yearley translates chart
But the class shed a whole new light on practical applications of math, such as avoiding being sucked from San Francisco Bay under the Golden Gate Bridge in a very small boat and out into a very large ocean.

Our daylong paddle provided clear examples of how to judge current speed and time low and high tides to good effect, as well as interim periods of slack (water). I am a huge fan of slack, in the slang-ish sense that I would like more of it in general, not to mention minimizing physical exertion in the form of paddling. On this day, we spent a bit over 5 hours on the water with a mid-trip break of more than an hour, just my speed.

We launched from Horseshoe Cove at Fort Baker, on the Marin side of the bay, tucked into a natural hip pocket behind the Gate. Instructor Jennifer Yearley’s plan: Start off around slack tide (I was happy already), work our way up the coastline toward Sausalito,
hang a right across Richardson Bay to the point at Belvedere, and finesse the cross current of Raccoon Strait over to Angel Island.

Preparing to launch from Horseshoe Cove at Fort Baker

There, we’d break for lunch, then start our return on maximum ebb tide. In other words, go with the bay flow instead of fighting it. Paddling in these parts is not always so easy, considering the playful -- and sometimes treacherous -- personality of the bay. 

A brief stop to get our bearings before the crossing
Jennifer’s plan worked perfectly, plus she threw in a gorgeously clear and warm day at no extra charge. We also experienced a bit of rough water, courtesy of the synergistic effects of our tide and current classroom, providing a dash of adrenalin to spice up the return leg.

Now about that math. Over lunch, Jennifer explained “the rule of twelfths” – a way to figure out the time when a tide will be at maximum flow – and the “50-90 rule”, which estimates the current speed between slack and maximum tide. You may easily look up these terms online, but there’s nothing like an on-water class to focus the attention of a kayaker, math-challenged or otherwise. One tip: Even Jennifer never tries to do the calculations on the way to a paddling destination -- advance homework is a must.
She also used a chart of the bay to explain what those colors and squiggly lines and symbols meant – such as rocks that might lurk just below the surface. Again, practical.
A nearly fog-free view of the bay from Angel Island....
...attracted a flotilla of other kayakers after we arrived
This is not to say that our class was entirely a paddle-by-the-numbers experience. I had forgotten just how beautiful the bay can sparkle on a fogless day. Temperatures felt balmy and panoramic cloudscapes slowly evolved over our heads. Sailboats, kayaks and one massive freighter dotted relatively smooth water for most of the trip.

On the way up toward posh Sausalito, we passed a large facility with tanks that looked like giant bathtub stoppers – until the smell of sewage treatment wafted our way. Given the multi-million-dollar residences that ring this shoreline, it must be some of the most affluent effluent in California.

On to Belvedere, another piece of nosebleed-priced real estate, where we encountered wave after wave of cormorants flying by – more than any of us had ever seen. Like us, the cormorants were headed in the general direction of Angel Island, a state park favored by paddlers and ferry-carried visitors alike.

Cormorants led the way around the point at Belvedere

We found a semi-secluded picnic table to spread out lunch next to Jennifer’s marine chart and enjoyed the nearby by views framed by agave and century plants as we discussed various bay flow factors. On this particular weekend, they included the gravitational effect of an extraordinary "Super Moon."
A little "chaos" in the tide race at Yellow Bluff 
On the way back to Horseshoe Cove, Jennifer coached and cajoled us into a brief side-trip on rough water at Yellow Bluff, where the ebb tide creates a “tide race” – an area where tide, current, wind and topography clash -- or “chaos” as Jennifer so aptly put it. Math, it would seem, can be quite exciting after all.


For some basic navigational tools to paddle San Francisco and beyond, check the links in the right-hand column of this page under “Information, please.” Jennifer also recommended The Tidelog publications, a handy collection of location-specific tide and current info in an easy-to-read format. The Northern California edition costs $20, including shipping.

Even the bay couldn't resist pull of a Super Moon
Read all you can, but this is another case where hands-on-paddle experience is hard to match when you have an instructor with top-notch paddling and communication skills. Contact Jennifer Yearley at River & Ocean, a collective of certified paddle sports instructors.

© 2016 Glenn Brank