Ebb and Flood: The Science of Tides

IMG_2784Tides are the most consistent variables in our surfing lives. The Ocean is always either receding or approaching your shoreline.  It is a constant reminder of the geometry and power of astronomical forces. Tides erode coastlines, impact marine ecosystems and even facilitated early life leaving the sea. Rising tides can pull swell onto a beach while dropping tides can focus wave energy to a shallow sandbar or reef. Tides are caused by the gravitational dance between the Earth, Moon and Sun.

Gravity is a fundamental force that attracts every object to every other object. It’s the force that brought Newton’s apple to the ground and the force that accelerates a bodysurfer down a wave face. The more massive the object, the stronger it’s gravitational pull. The closer two objects are, the stronger the pull of gravity between them. This pull between objects is called a tidal force.

Size comparison. -GSU.edu
Size comparison. -GSU.edu

The Moon, Earth and Sun are freaking huge. About 36 Moons can fit inside the Earth and 1.3 million Earths fit in the Sun. Although much much less massive than the Sun, the Moon’s gravitation has a stronger impact on Earth because it is much closer. The sun is 93 million miles away from the Earth while the Moon is only 240,000. Much like an apple is pulled to the ground, the Ocean is pulled toward the Moon. Luna’s tidal force tugs on the Earth, pulling the Ocean off some beaches for low tide and onto others for high tide. The force also impacts the Earth’s crust and atmosphere but only fractionally compared to liquid water.


Tides are caused by two bulges formed in the Ocean. One from the tidal force toward the Moon and the other on the opposite side of the Earth caused by inertia as our planet spins. This is the same centrifugal force that keeps the water in the bucket when you swing it  over your head. The bulges follow the Moon and the spinning Earth around the globe. When a bulge passes your beach, the tide rises.

Lunar Phases
Lunar Phases

The monthly tide calendar parallels the monthly lunar phase calendar. New Moon is the alignment of Sun, Moon, Earth. We do not see the Moon because all the light is bouncing off the Far Side. This formation of three bodies in a line is called syzygy and it amplifies the tidal forces on the bodies. During New and Full Moons, the alignment of the Earth, Moon and Sun creates greater tidal range. Higher highs, lower lows and more dramatic swings; this is called the spring tide. Not named for the season, but because it “springs forth.”

Notice the spring tides near Full and New Moon.
Notice the strong spring tides near Full and New Moon.

As the Moon orbits the Earth, it “waxes,” growing and showing more of her face each day. After about 14 days the alignment is Sun, Earth, Moon, with the full face of Luna reflecting light. Then Luna wanes- shrinking each day until New Moon again two weeks later.  The rest of the tide chart flows up and down between these points with the first and third quarter Moons having the smallest tidal range. These are neap tides.

The differences between tides from day to day and month to month is the result of astronomical motions. Luna’s orbit around the Earth forms an oval or ellipse. Sometimes she is closer to Earth than other times. King tides are the highest tides of the year and exist when the Moon is closest to the Earth and in syzygy alignment with the Sun.

7-9Ebb is the decreasing tide while flood tide is the increasing. The moment the tide changes is called slack water.  There is 6 hours between each high and low. Tomorrow’s high tide will be about an hour later than today’s. Tides vary greatly all across the globe depending on factors like geographic location, local weather/swell and shoreline geology. The East Coast of the US is semi-diurnal. This refers to two highs and two lows each day of roughly the same height. The West Coast is mixed semidiurnal: two highs and two lows each day with different heights. The Gulf of Mexico is diurnal: one high and one low each day.

Bay of Fundy, Nova Scotia. Largest tidal range on Earth.
Bay of Fundy, Nova Scotia. Largest tidal range on Earth.

Three billion years ago, the Moon was much closer to the Earth, the tides rose thousands of feet over the land and then back to sea. Today, the greatest tidal range exists in the Bay of Fundy, Nova Scotia. Tides are focused in and out of the bay resulting in a 50ft.+ tidal change. The lowest tidal ranges of just a foot occur in the Mediterranean, Baltic and Caribbean Seas. The middle of Ocean basins also experience minimal tidal changes. Hawaii’s tides rarely change more than 2ft. However, California’s tides exhibit much more dynamism. California king tides can approach 8ft. with an accompanying -2ft. low.

High tide pushing up the beach.
High tide pushing up the beach.

Tides impact waves in a variety of ways. Surf spots that prefer certain tides are referred to as tide dependent.  Some spots are flat until a tidal push focuses the energy on the beach. Other spots stop breaking when the tide floods because the water becomes too deep for the waves to shoal. As a general rule, incoming, low to high tide is preferable for many surf spots. Low tide can create fast, hollow, plunging waves. High tide often produces slow, mushy, spilling waves. However, many shorebreak womps prefer high tides pushing up the beach.  Changing tides can also alter the strength and direction of longshore and rip currents.

Death, taxes and tides. The great English poet, Geoffrey Chaucer, wrote “Time and tide wait for no man.” They are predictable and unstoppable. Tides are the only variable in surf forecasting that are concrete and certain.  Waveriders can feel the rhythm of the tides. We experience the astronomical forces on a different level than the mathematicians and physicists.

NOAA Ocean Service Education
National Geographic Education


Perspectives: The Bodysurf Contest

Bodysurfing contests are unique among the water bound. With no board space for advertising and virtually no equipment to construct franchises around, bodysurfers who compete exist in an emerging space. While bodysurfing contests are not new, the number of expression sessions and bodysurfing competitions is growing by the year. We decided to reach out across the spectrum of torpedo people to get their 2 cents on the value of bodysurfing competitions.

Sean at Point Panic
Photo by Doug Palama


Sean Enoka

Location: Oahu

Additional Info: 2011 Point Panic Champion


“Bodysurfing Contests are an integral part of Hawaiian bodysurfing. For specific spots, it’s just an excuse to surf an iconic break with a very small number of friends, etc. Take Pipeline, how else are we going to get the lineup to ourselves?

It’s also a chance for us to all come together and compete and push the sport. I just love to sit and watch what everyone is doing and all of the different tricks or styles that are on display.

Unfortunately there are some negative vibes during events when someone feels slightly by not receiving a particular score or when not placing at the top of the scores. I think that a definite area of improvement on contests is to upgrade the scoring/judging process, but typically these events and judges are basically volunteering their time, etc.

For me personally, I am trying to be the best bodysurfer that I can be, so when I compete it’s with passion and purpose to improve and do well at what i love to do. And I just love to “battle”, but sometimes there are others who take the competition in a different direction to “win at all costs”. I’ve seen people jockey for position, swim through people water polo style which can lead to arguments, etc. But for me, the competitions about what you can do ON THE WAVE, and not how you can out position someone else and so on.”

Photo by unknown

Henrique Pistilli

Location: Fernando de Noronha, Brazil

Additional Info: Creator of courses in self-development through bodysurfing



“I think the future of bodysurfing is not on contest basis. Contests are good, and I like it a lot. But I feel that bodysurfing is more powerful as a “dynamic meditation”, as a process for self-development in interaction with nature…. So the future… I feel it is all about big celebration meetings, exhibition sessions, courses for adults and teens, videos, pictures, art, poetry!”

JT Perspectives
Photo by John Minar

J.T. Nickelson

Location: Irvine, California

Additional Info: Wedge Crew Member, Pipeline Bodysurfing Contest Finalist


“I have mixed feelings regarding bodysurfing contests. On one hand, I think they are fantastic. A collection of talent all in one place to showcase their style of riding and being judged by their peers, who should be accomplished bodysurfers themselves. The downside is this, they aren’t usually judged properly. A rider should be penalized for not using their hands, they should not be rewarded for flailing and ruining a wave, they should not be rewarded for blowing a ‘makeable’ barrel. They should not be rewarded for being slow, and just getting length of ride by going straight. The purpose of contests is to bring everyone to another level.

I think a great example of current bodysurfing contests is in the movie Dog Town Zboyz (the drama, not the documentary). they go down to SD and their style isn’t judged on their progressiveness. I think contest judges need to have meetings on what ISN’T going to be scored high. Like long rides where the rider cannot maintain control, their hands constantly pearl, etc. I’m adamant on this as if we are to progress as riders, we need to up the game – globally.”

Photo by Mike Sidebottom

Pierce Michael Kavanagh

Location: La Jolla, California

Additional Info: Director/Cinematographer for the upcoming film What the Sea Gives Me, Spreader of Stoke

 “I think competing is cool in good waves for others but I would rather cruise.”


Photo by Andy Quinn

Thomas Van Melum

Location: Newport Beach

Additional Info: Pipeline Bodysurfing Contest Finalist, Member of Team Blacksheep, Wompton Runner-Up



“Competitions are important to showcase prowess and expertise. You know why people don’t like competitions? They don’t want to stand up and be vulnerable, be measured, be exposed for what they really are. And besides, how else are we going to be able to prove that Team Blacksheep and The Wedge Crew are at the top of the bodysurfing game?!?

Lastly, good competitions give students of the sport an opportunity to see the best going head to head. Shit, they might do something they’ve never done before, and we could all learn from it. Ok one more thing, how else are you going to meet Marc Cunningham and eat lunch with him?”


Photo by Nicolas Risch
Photo by Nicolas Risch

Fred David

Location: Hossegor, France

Additional Info: World Bodysurfing Championships Champion, Pipeline Bodysurf Classic Runner-Up, Waimea Slam ’11 and ’12 Champion

 “I think on one hand, contests are good because they bring a lot of bodysurfers together at the same time. It s a good place to learn, to see what the other are able to do. It also bring medias around our sport. It’ s pushhing the sport. On the other hand, I feel like I am never really happy after a contest.

In France there is always something witch sucks. One day the waves will be really bad, the other day the judges won’t even know how to judge bodysurf, another day the guy in charge of bodysurfing will do his own things and personal choices and forget about everybody else. Contests are good if you do it for fun and don’t expect anything at the end of the day… I have no problem with losing when the other are better, or when you haven been good. But I really hate it when it is not fair! I would love to see one day a real World Bodysurfing Tour. 2 or 3 contests held on real world class bodysurfing waves, with good judges, and the best bodysurfers in the water!”


Brush Strokes: Shane McClatchey

Shane“Right when you think you have the ocean all figured out it changes your mind.”

Shane grew up in Pleasure Point, New Jersey. Surfing spawned an interest in bodysurfing nasty storm swells. He attended the Laguna College of Art and Design and was gracious enough to share some of his work with us.

"Painting waves started from the perspective as being on the board, now I've become more interested in painting everything going on in the water."
“Painting waves started from the perspective as being on the board, now I’ve become more interested in painting everything going on in the water.”


He began shaping his own handplanes and not long after began using the wood he was finding for his art as well.
He began shaping his own handplanes and not long after began using the wood he was finding for his art as well.


Bodysurfer in Space
“As an artist, bodysurfing is a beautiful thing to see. The surfer’s body is locked into the wave with no board in between.”


"In my artwork I want to keep searching and exploring the world of bodysurfing and everything else in our aquatic lives..."
“In my artwork I want to keep searching and exploring the world of bodysurfing and everything else in our aquatic lives…”


"A perfect day would be could be head high and glassy in New Jersey in the fall or diving for calico bass and sheepshead off of Catalina. Any day where I'm in the water longer than I'm on land, followed by a fire and some beers with good people."
“A perfect day would be could be head high and glassy in New Jersey in the fall or diving for calico bass and sheepshead off of Catalina. Any day where I’m in the water longer than I’m on land, followed by a fire and some beers with good people.”


For more information on Shane’s work, you can check out his website or email him at shanemcclatchey@lcad.edu


Ode to Summer

Summer Solstice
The Sun’s energy reaches north to the Tropic of Cancer.
Long days, warmer water: shed the neoprene shackles!
Pack a bag, grab a bike, surf til 9.
Long beach days, sandy feet, sandy everything.
Season of skin.
Bikinis and womper speedos.
Tans and burns.
Move beyond the gray and gloom.

South swells, birthed off Antarctic ice,
Make their long, lumbering trek across the equator.
Gracing our shores with their steep angled, inconsistent energy.
Hopeful for intense tropical lows spinning off Baja,
moving north into our swell window.

The 5 is jammed- beach parking is nonexistent.
30 guys pitched with the lip together at the local womp.
The South Pacific is inactive.

No worries.
High Sierra passes are open and alpine meadows bloom.
Worship in the Granite Cathedral.
Find a dark sky…observe the heart of the Milky Way.
Stunning clouds of galactic star stuff.IMG_8794


Yes, the North Pacific winter provides better energy.
But a pure New Zealand south swell,
sans wetsuit,
is something to cherish.
Lines stack up, lefts reel along the coast,
unloading in the warm summer air.


Visions of the Month: June 2014

Each month we invite you to send in your most stoke soaked shots. Here are our favorites this month:

Ron Pringle on the left
Ron Pringle By: Larry Beard


real barrel
Felipe Voigtel By: Kevin Brooks


Alex "Bigfoot" Torres By: Tim Connelly
Alex “Bigfoot” Torres
By: Tim Connelly


By/Of Joseph Buskirk
By/Of Joseph Buskirk


Eric Phleger By: Max Phleger
Eric Phleger
By: Max Phleger



Thanks for all your entries! For a chance to have your photo in our Vision of the Month collection, send in your photos to swelllinesmag@gmail.com and label the email “Vision of the Month.”  Please include name of rider and photographer.