Waves & Surf

Bob in surf-crop

The following article is by Jeff Adler, ACA L4 Coastal Kayaking Instructor.

SURF ZONE SAFETY

The Surf Zone is an exhilarating place to paddle. Paddling in the surf can be fun and challenging for some, and for others it can be a source of anxiety and stress. Whether you are planning a day of playing in the surf or just need to get through the surf break to get to your destination, knowledge of the conditions you will encounter and the associated risks is paramount.

The first step is to know what your skill level is, and if your equipment is appropriate for the conditions.  In order to venture into the surf zone, you must have gear that is intended for and safe to be used in these conditions. There is no place for recreational kayaks in the surf zone or on any big water (oceans or the Great Lakes). These boats lack the safety features of sea kayaks and are intended to be used on small lakes, ponds or slow moving streams and only close to shore. Sea kayaks have bulkheads and dry hatches creating areas of floatation/buoyancy for safety as well as storage. In a sea kayak, the boat will remain afloat even if the cockpit is flooded due to the air in the dry hatches. The bulkheads (internal walls) are positioned to allow the water to easily be emptied so an assisted or self rescue can be performed. Sea kayaks also have smaller cockpit openings that can be covered by a spray skirt to keep water out, thigh braces to improve boat control in conditions, and deck lines that will allow one to stay in contact with the kayak after a capsize and aid the rescuer in performing an assisted re-entry.

When talking about your personal kit (gear)…
• Always wear your PFD!
• A helmet is important to protect your head in a capsize.
• You must be dressed for the swim, so a wet suit or dry suit may be needed depending on the water temperature.

Before getting on the water, an honest and objective evaluation of your skill level is important. Are you able to perform a wet exit? How comfortable are you in the wind and waves? Are the current conditions bigger than what I can safely handle? Because of the great forces at work in the surf zone, this is not a good place to start learning on your own. Begin with good quality instruction and never go out alone. Use your time with an instructor to learn the necessary skills. The time to push the envelope is when you have a highly skilled instructor nearby. The important skills to learn include braces, boat control in wind and waves, learning to paddle through the surf zone and paddling in on the back of the waves.  It can be difficult to find appropriate surf conditions for practicing these skills, but when you don’t have access to conditions, time on the water can still be used to practice the skills needed when an opportunity to get into the surf presents itself.

Rolling is an important skill which can prolong your time in the surf by keeping you warm and dry. It can save the energy needed to perform rescues or swim back to shore. Rolling is also the best option for self rescue. Even if you do not have a reliable roll, learning the set up and proper wet exit techniques will better protect you during a capsize in the surf.  This is a skill that you will want to learn on warm, calm water first before you are ready to work on your rolling skills in rough water and surf.

It is important that paddlers understand the dynamics of the surf zone and the risks that are associated with the various conditions that exist there. Surf zone conditions include:
Rip Currents – These are powerful and potentially dangerous channeled currents that move water from the shore back out to sea. They account for more than 80% of life guard rescues. Rip currents extend from the shoreline through the breaking waves. If caught in a rip current, swim or paddle parallel to shore until out of the current and then attempt to swim/paddle back to shore. Most of the problems occur when one tries to swim/paddle straight in against the current. You will quickly become tired, fatigued, and anxious.  On a positive note, rip currents can provide a good route out through the surf when you are ready to leave the beach as the waves are generally flatter in the area of a rip current and the current is carrying you in the direction you want to go.
Shore Break – This is a condition where waves break right on to the shore. This occurs where the transition from deep to shallow water happens rapidly. Breaking waves are powerful. The weight and power of these waves slamming you onto the shore can cause serious injuries. Head injuries and spinal cord injuries are the most severe, but broken bones of the extremities and blunt chest or abdominal trauma can also occur.
Rogue Waves – These are larger than average waves that can be unpredictable. They will break farther from shore than the majority of the waves on a given day catching you off-guard and knocking you over/out of your cockpit or on to rocks or cliffs.
On-Shore and Near-Shore Hazards – When paddling in the surf zone, you must always be aware of your surroundings. Is the ocean/lake floor a sand bottom, or is it rocky?  Are there cliffs or rocks as you approach the shore or where the waves are breaking?  Will you be pushed towards any of these hazards? You must be aware of your surroundings before you head out. Take time to scout out the areas where you intend to paddle, ask locals for their recommendations. Local knowledge is a great resource and should always be sought and considered where available. Local paddlers or surfers are often your best resource as most other boaters do not navigate in these waters very close to shore.

The surf zone is a dynamic place to paddle, fun and exhilarating for some, or a dreaded necessity for others.  Either way, everyone who paddles on open water is likely to have to paddle in or out through the surf at some point.  As such, proper kit and training prior to heading out into the surf zone is important. Learning and practicing the skills needed to be safe will make the experience more enjoyable regardless of your goal.

Have fun and Paddle Safely!

Lake Geneva 10-25-08 waves crop

The following article was written by Sherri Mertz, ACA L4 Coastal Kayak & L3 River Kayak Instructor

ALL ABOUT WAVES

As paddlers, we encounter waves every time we go out on the water.  Recreational kayakers on placid lakes and rivers may only have to contend with small ripples or the wake from passing power boats, but sea kayakers must be prepared to deal with wind driven waves and breaking surf, and whitewater kayakers need to know about standing waves, wave trains, and hydraulics.  In order to be better prepared to paddle in waves, it is helpful to know something about how waves are formed and what forces are at work within the wave.

Parts of a Wave

Wave Diagram

Wave period is the time (in seconds) that it takes for the crests of two consecutive waves to pass a fixed point

Wind driven waves found on lakes and oceans are the result of three factors:

  • Wind speed: The harder the wind is blowing, the bigger the waves will become.
  • Wind duration: The longer the wind blows from the same direction, the bigger the waves will become.
  • Fetch: The greater the distance that the wind travels over the water, the larger the waves will become.

These three factors work in combination to produce waves on the surface of the water.  The size of the wave depends on the exact values of speed, duration, and fetch that exist at the time.   Here are some additional terms that are helpful to understand when talking about waves.

Seas vs. Swells

Seas are locally produced wave conditions, characterized by choppy, confused conditions (what we mostly find on the Great Lakes).  These waves have been created by local winds.

Swells are waves coming from a distance, characterized by regular wave sets and patterns.  Swells are formed as waves move across the ocean.  Faster waves catch up with slower waves and combine to form larger waves.  Over time, these waves become smoother and more regular.  Swells reaching the West Coast of the United States may have started as storm-produced waves near Japan.

You can have conditions in which large swells are present with no wind to ruffle the surface of the swell.  You can also have conditions in which there are just locally choppy seas.  Finally, you can have seas that develop on top of swells when a local wind causes the surface of the swells to become choppy and confused.

Fully Developed Seas

When wave heights reach the maximum that can develop for a given wind velocity, fetch, and duration, this is referred to as fully developed seas.  The table below gives an idea of what it takes to reach a fully developed sea for a given wind velocity.  At 10 knots of wind, you need at least 10 miles of fetch and a wind duration of 2-4 hours to reach a fully developed sea in which the average wave heights will be just under one foot.  Once you reach the state of a fully developed sea, greater fetch and duration will not result in larger waves unless you have higher wind velocities.

Wind Velocity

(knots)

Length of Fetch

(nautical miles)

Duration of Wind

(hours)

Average Wave Height (feet)
10 10 2-4 0.9
15 34 6 2.5
20 75 10 5
25 160 16 9
30 280 23 14
40 710 42 28
50 1420 69 48

*Table information taken from the book, “Waves and Beaches” by Willard Bascom

Wave Sets

Waves tend to arrange themselves in patterns.  You may get a series of somewhat larger waves and then a lull where the waves are smaller.  Larger wave sets often group themselves in threes, but this is not a hard and fast rule.

Types of Waves

  • Breaking – the angle of the rising sea bottom influences the way a wave breaks
  1.  Surging – very steep beach (think cliffs)
  2.  Dumping or Plunging – moderately steep beach
  3.  Spilling – flat or very gradual sloping beach, safest type for surfing
  • Clapotis (rebounding or reflecting waves) –found near cliffs and breakwalls, crests  will be higher than normal and troughs will be lower than normal in these areas.
  • Close-out – long sections of the wave break simultaneously
  • Refracting – waves bending around a headland, island, etc.
  • Standing – a wave that stays in place as water flows past (tidal races, rivers)
  • Wave Train – series of standing waves that develop in the deep channel of current (rivers and tidal races)

Why does a wave break?

A smooth, unbroken wave will lift a boat, but does not generally cause a capsize.  The energy within an unbroken wave is circular.  An individual water molecule will be lifted and then lowered as the circular wave energy moves through the water toward the shore.  Paddlers on larger waves may lose their balance and capsize, but it is technically not the wave that is causing the capsize. It is the paddler who is falling.  However, when a wave begins to break, that wave energy is now being channeled in a new way.  It is being released to move the water molecules shoreward. In shallow water, the sea bottom slows the base of the wave’s movement toward shore so the top gets ahead and breaks.  Imagine a spinning tire floating on the water’s surface heading toward shore.  As long as the tire does not touch bottom, it keeps spinning unchanged.  As soon as the tire comes in contact with the bottom of the lake/ocean, that bottom portion of the tire slows down.  If the tire is very elastic and stretchy, the top of the tire would continue moving toward shore at the same speed because there is nothing to slow it down.  It would become elongated into an oval shape.  This is similar to what happens to circular wave energy just before a wave breaks.  A kayak that is caught in front of a breaking wave will be knocked over if the paddler does not take steps to prevent a capsize.

Waves will begin to break when the water depth is approximately 1.3 times the height of the wave. If the waves are about 2 feet deep, they will start breaking in about 2.5 feet of water.  It really isn’t important to have an exact formula since we can only judge the approximate height of the waves when we’re out on the water anyway.  Knowing this information just gives us some idea of how deep the water is when we see waves breaking, or when looking at a chart, we can anticipate where we might encounter breaking waves based on the wave heights we are seeing.  If you see a specific spot where a breaking wave is consistently appearing in otherwise non-breaking waves, you should assume there is a rock, reef, or some other debris that is close to the surface causing the wave to break.

What happens to a kayak when hit with a breaking wave?

It first of all depends on where the wave hits your kayak and the direction you are paddling in relation to the wave.  If you are heading out to deep water from the shore and the wave hits you head on, you will hopefully break through the wave if it is not too large and you have a reasonable amount of forward momentum.  If you are heading back into shore and the wave catches you from behind, you will feel the back end of your boat being lifted up by the wave and it will start pushing your boat forward.  If you can maintain the direction of your kayak and keep it pointed toward shore, you will be surfing.  More often, as the breaking wave catches the kayak from behind and begins pushing it forward, the front end of the kayak is caught in slower water.  As the back end is accelerated by the breaking wave, the kayak gets pushed sideways because the front end is going slower.  Once the kayak broaches (turns sideways to the wave), you must either be edging your kayak into the wave and bracing on that side, or you are going to get flipped over toward shore.  The same thing will happen if you are paddling parallel to the shore and a breaking wave hits you from the side.

Staying Safe in Waves

First of all, you want to avoid getting into waves that are well beyond your current skill level unless you are in a relatively safe environment, working with a more experienced paddler who is teaching you how to paddle in waves.  To avoid getting into a dangerous situation, check the wind forecasts for the area in which you plan to paddle.  Knowing wind direction, wind speed, and the fetch at your launch location will tell you a lot about the size of the waves you might encounter.  Marine forecasts often include wave forecasts, but these can be very misleading since the forecasts are usually intended for fishing boats and ships that travel much farther from shore than where kayakers are likely to be paddling.

When first learning to paddle in waves, an on-shore wind will be safer than an off-shore wind because you will be carried back towards shore if you capsize.  An off-shore wind will carry you farther from shore and away from assistance.  You should also have spent a significant amount of time in flat water perfecting your boat control skills in the wind before venturing out into waves.  On the ocean, there is opportunity to paddle in large swells with little or no wind.  In the Great Lakes, this is a very rare occurrence.  You should not be tempted to go out paddling in winds over 15 miles an hour until you have more experience handling your kayak in stronger winds.  When winds are approaching or exceeding 30mph, you should be staying on shore, especially if the winds would be blowing you away from the shoreline.

What should a paddler do to avoid capsizing in waves?

In smooth unbroken waves, it is best to try to stay loose and relaxed at the hips.  The boat may rock in the waves, but you want to keep your head and shoulders over the kayak. Think like a hula dancer.  When you watch hula dancers, their hips may be shaking back and forth like crazy, but they generally keep their head and shoulders relatively still and centered over their hips.  In your kayak, it really doesn’t matter how much the boat is rocking back and forth if you can keep you center of mass over the kayak, you will likely stay right-side up.

To improve your stability, keep paddling.  An active blade in the water is like doing a bracing stroke.  You are most likely to capsize when you are not actively paddling.  You can also use a lower stroke angle.  Using a low-angle forward stroke will place your paddle blades further from the sides of the kayak.  Your paddle will act almost like an outrigger.  Finally, you can cant your paddle blade slightly when doing forward and sweep strokes so that you are doing a little bit of a low or high brace while still performing your strokes for propulsion and turning.

When hit with a breaking wave from the side, or if broached when surfing, a paddler needs to edge his/her kayak aggressively into the wave. Depending on the force of the wave, the kayaker may need to actually lean his/her body out over the wave.  A low brace placed out to the wave side gives good support while the kayak is being pushed toward the shore.  As the wave begins to peter out losing its energy, the paddler needs to get his/her center of mass back over the kayak or he/she will capsize towards deeper water.  If the paddler sits up too soon, before the wave has lost enough energy, the kayak will get dumped over toward the shore.  Either way, you’ll immediately know what you did wrong by the direction in which you capsize.

Paddling in waves can be challenging, fun, and exhilarating for many sea and whitewater kayakers.  It does require some commitment of time and practice to become proficient.  Water has tremendous power and large waves can prevent emergency responders from getting to you, so it is imperative that you use common sense when it comes to seeking out opportunities to paddle in waves and surf.  Wear a life jacket.  Get instruction.  Practice with other skilled paddlers.  Don’t exceed your skill level.  With time and effort, you will improve and be able to test yourself in more challenging conditions.

Paddle Safely!