Understanding Waves


Waves can turn the sea into the most spectacular and thrilling of wild swims, a natural fairground ride of wildness and surging energy. Equally, waves can suddenly turn and become unmanageable as a big set comes through, or where there’s a sudden collision between a wave reflected from a reef or cliff with an incoming one. As a swimmer, you can learn to both have fun on the limits and to deal with the unexpected when it happens.

Waves on beaches tend to come in ‘sets’ or groups of several larger waves, interspersed with smaller waves. Sometimes a set of unexpectedly large waves might come through. Don’t turn your back on the sea!

There are three main types of wave that you might encounter on a beach. Broadly the geomorphology of the beach determines the types of waves and vice versa.

Dumping/Plunging Waves and Shore Break:

These waves rear up suddenly and break with great downward force; the classic barrel or tube waves beloved of surfers are this type. In places where they break very close to the shore they are known as shore break. The dangers of these include physical injuries, especially spinal fractures. They are also dangerous to weak swimmers because they will knock you off your feet and pull you out. And of course you then have to get back in through the shore break.

Never body-surf a dumping wave.

Spilling Waves:

These occur on more gently-sloping beaches, and tend to roll and grow before breaking gently from the top. They are less steep than dumping waves, and the force pushes you along the surface so you can body-surf them.

Surging Waves:

These don’t seem to break in a dramatic way, but rather bulge and then suddenly surge up the beach far further than you expect. The danger of this type of wave is that it can pull people from quite high up the beach into the sea. Tsunamis are surging waves.


This is the pull from waves returning from shore to sea. It might be what’s meant by undertow, although this is a misleading name. This current runs along the bottom, seawards, beneath the incoming waves. To be clear, it won’t pull you under, nor will it hold you under. Because it runs along the bottom, if you’ve been pulled off your feet you’ll go with it. But because you’re buoyant, you will pop up to the surface.


Negotiating Waves and Wipeouts:

When trying to negotiate waves it’s good to play around and learn how to deal with them. In the shallows as a general rule stand sideways on to a wave with your feet wide apart. Once you’re above waist-height in the water, swim over waves, or if they’re breaking, dive under them with your arms out in front to protect your neck. Learn the techniques for swimming through surf, including porpoising.

When making your way back to shore, swim and look back under one arm every stroke to see what’s coming. If the wave isn’t breaking, it’ll move you towards the shore. If it is, it’s better to turn and dive back under a breaking wave if you don’t know how to body-surf, or if the waves are particularly big or of the wrong type to body-surf safely.

If you do get wiped out, there are some basic principles that will help you to recover:

  • Take a breath if there’s time.
  • Relax and go with the turbulence, or if you prefer, adopt the foetal position. Don’t fight it.
  • As the turbulence lessens, push up to the surface and be ready to deal with the next wave.
  • If there’s another wave on top of you, grab a quick breath and dive under the wave.
  • Sets of big waves tend to number around 5, but there might be a few more. Stay calm, a smaller set will appear and give you the chance to get back into control.


There are various types of surfer, from the stand up experts to kids on polystyrene boards. If you’re in an area where there are surfers ask them how best to stay out of their way. Often they don’t have the ability to avoid you – if they can see you at all – and you certainly don’t want to be hit by a cartwheeling board.
Words : Lynne Roper
Pictures : See Credits