I spent most of my twenties with a tide book tucked into my back pocket. I replaced it for a new one each January but by summer its spine would be held together by duct tape, the pages scribbled with shorthand notes in blue ink about wind conditions and swell angles. The same information was obviously online but this was a journal as much as a tide table. By proximity, it was also much closer to my heart, its curvature along one leg shaped by weight and friction into an approximation of my left butt cheek.
At that point, the tide seemed to be the most influential dictator of my lifecycle. I never planned anything without first consulting “the book,” to determine whether I could get colossally drunk, for example, head inland, or otherwise engage in activities that might interfere with low-tide barrels. I was enamored with a certain beachbreak in San Diego.
Swamped mornings—endured roughly a week at a time, often throughout winter—usually meant going straight into work rather than a pre-rinse on the dawn patrol. Early low tides on the other hand meant loss of sleep in good cause and I would spend most of those weeks in an REM-deprived, endorphin-satiated trance, promising myself and my coworkers that I’d pull my shit together when the sine wave said so. Low-incoming afternoons were excuses to slither along the rows of cubicles, then out the backdoor of the warehouse, ideally unobserved, hoping the wind would die before dark, just as the water filled in over the sandbanks.
The way I saw it, swells rose and fell but they were more overt, thus easier to assess with the naked eye, not to mention with online cameras. Paired with the predominant diurnal wind pattern, it was relatively simple to decode when and where to surf as long as the tide was cooperative. And since the tide seemed to be the only factor I could plan for ahead of time, over a much longer period, I made a habit of simply using it as my main predictive signal, consulting it primarily, sometimes weeks in advance, setting my schedule accordingly, and hoping for the wind and the swell to follow.
I remember being asked by an acquaintance around this time whether there was a character trait that separated “surfers” from people who simply owned a surfboard. I replied—without hesitation—that if someone didn’t know the tidal phase, at any point in the day, on any given day, to within a rough estimate of accuracy, it was a sign they were the latter.
As much as the tide influenced my life, though, I didn’t delve much into the how and why of the forces governing it. The alignment of the moon and the sun and the earth, and the gravitation pulling on our oceans, was all the theory I needed. Rotation and orbit played a factor but that just meant adjusting for super low tide mornings versus super low afternoons between summer and winter.
I was confident at best, condescending at worst, in my knowledge. Some of those traits have washed off since then but, until recently, I did retain a belief that my understanding of the tide was at least above average. The reality, of course, is that I was unaware of how much I was unaware of—a fact I realized over, and over, and over again as I read two recently-published books on the subject.
Tides: The Science and Spirit of the Ocean by Jonathan White, and The Tide: The Science and Stories Behind the Greatest Force on Earth by Hugh Aldersey-Williams, each run about 300 pages and contain deeply-researched-yet-approachable reporting on tide history and (as titling suggests) tide science. One of the first things both authors highlight is that, while the tidal rhythms along our coastlines may be easy grasp, the tide itself, in its entirety, is such a powerful, complex, and massive natural phenomenon that its causes and effects continue to baffle some of the world’s best scientists.
At all times, there are so many tidal factors influencing our planet’s oceans (more than 400 in all) that I came to be not only awed by the sheer observatory and computing power required to account and track for so many variables, but also slightly baffled that such a feat of scientific understanding could be boiled down into a sine wave on a calendar.
Each day, astronomical gravitational forces from the sun and the moon pull on the oceans, which are further acted upon by the centrifugal force of the earth’s rotation and orbit, shallow-and-deep-water fluid dynamics, friction, resonance and vibrations dictated by the shape of oceanic and other basins, the declination of the earth on its angle to the sun, the declination of the moon as it orbits the earth, the 28,000-year cycle of the earth wobbling on its axis, divisions in the oceans broken down by sub-basins, amphidromic systems, salinity, water temperature, and seafloor topography. And that’s just the broad strokes.
Taken as a whole, these factors can explain the massive high and low tides present in some locations, the lack thereof in others, the seemingly anomalous single-high and single-low tides experienced in certain bodies of water, and why, at certain times of day, month, or year, sea creatures—surfers included—flock to our planet’s intertidal zones and coastlines to harvest the spoils of flux or harness the tide’s powers.
Both books probe the science and the more humanistic aspects of our relationship to the ocean as a result of the tides. And both, for anyone interested in not only the cause and effect of gravity on fluid, but also how we respond to that phenomenon as sentient beings, provide storytelling, scientific breakdowns, and myth analysis that will resonate with any reader who has spent time in or on the ocean.
Other similarities abound but the main differences between these two books seem to be in their authorial backgrounds and focuses. While White is a lifelong sailor and a surfer (who, full disclosure, has written for TSJ about the tides), Aldersey-Williams is more of a landsman, by his own admission.
These differing viewpoints become apparent in each writer’s approach to the material. Aldersey-Williams goes directly into the written record, probing for tidal anecdotes, literary references, and scientific research that spans from the Greeks to the Romans and on to Newton through modernity. The first line of his introduction proclaims: “This is not a book about the sea.” From that point forward, one gets the sense that, while Aldersey-Williams does make forays out into the world to visit various locales of tidal significance, most of his research and impetus came from indoor sources, found dry and warm, in the stacks of a library.
White on the other hand begins his introduction by inviting us onto a sinking sailboat, which he’s captained into a remote Alaskan inlet. He then recounts how he was nearly doomed, but ultimately saved by the massive local tidal swings. This starting point couldn’t be more different from Aldersey-Williams’ and the globe-trotting that follows—to some of the wildest corners of the earth, for visceral interactions with the tide, each experience intended as a launching-point for him to unpack specific tidal characteristics and scientific revelations—suggests that White’s is the lens of a seaman.
In many ways he also delves more deeply into the minutia of the mechanics, done in an effort to help his readers (and I’m assuming also himself, ultimately) understand and predict real-world oceanic behaviors. In short, White seems interested in applying his findings—from his perch at the tiller, or his spot in the lineup—to his own watery environment.
Read as a pair they offer a depth of tidal knowledge I never could have imagined. Both have passages of compelling reading and information that would augment a field manual, though neither will fit in your back pocket. White’s book seems a little brinier than Aldersey-Williams’, however, its pages swollen with the moisture of its subject. And because of its author’s desire to join science, prediction, and observation from an immersive perspective—one side of his brain dipped in the ocean, the other in the laboratory—it seems to be the more relevant of the two, at least for surfers looking to apply its lessons at sea level.