NAVIGATION
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Rip currents

A rip current is a body of water that is moving out to sea. Rip currents generally occur when a channel forms between sandbars, and large waves have built up water, which then returns to sea causing a drag effect out to sea.  The larger the surf the stronger the rip current.  Rip currents are dangerous since they can carry swimmers out into deep water.

A rip current consists of three parts: the feeder current, the neck, and the head.  The feeder current runs parallel to the beach and is the source of the outgoing water.  Rip currents fall in to three types:

Permanent

The permanent nature is due to the ocean bottom and prevailing conditions changing very little.  Rip speed and power is proportional to surf size due to the extra water moving.  Rock projections, or other man-made projections such as groynes, drainage pipes or piers force lateral currents seaward to form permanent currents.  Rivers and tidal outflow are also of the permanent type.

 

Flash rips

The flash rip is temporary in nature for any given location.  It is caused by:

  • Stormy, heavy surf build-up with long wave sets increasing the volume of water above sea level.
  • Sudden change in offshore sandbars/banks.  It will appear suddenly and usually without warning and is relatively short lived.

 

Travelling rip

A travelling rip current is propelled along the beach front by a strong lateral current in the prevailing wave direction.  These rips travel away from the waves that feed them.  A travelling rip may move over large segments of beach before it dissipates

There are various ways of identifying a rip current from the shore, and these are listed below:

  • Muddy, discoloured water, due to sand stirred off the bottom.
  • Foam on the water’s surface extending beyond the break.
  • Waves breaking further out on both sides of the rip.
  • Debris floating seaward.
  • Rippled appearance, when surrounding water is mainly calm.  The lack of surf can attract unsuspecting beach users.
  • Darker deeper water.

 

How to Escape from a rip current

If you get caught in a rip current – DONT PANIC!

If you are tired, or not a very strong swimmer, ride the rip out from the beach, then swim parallel to the shore for 30 to 40 metres to where the waves are breaking.  You can then swim safety straight back to the shore, out of the rip.  If you are in difficulty, attract the attention of the lifeguards on the beach.

Stronger swimmers, after assessing the width of the rip current, should swim at a 45 degree angle across the rip current.  After a short swim you can check whether a sand bar has formed near the edge of the rip.  Continue to swim at a 45 degree angle until you reach the shore.  If you get into difficulty, attract the attention of a lifeguard.

Waves

The four main types of wave are: plunging, spilling and surging.  More detail on each of the types is given below:

Plunging or Dumping wave

This wave breaks with tremendous force and can easily force a swimmer to the sea bed. They usually occur at low tide when sandbanks or reefs are shallow.

Spilling wave

This wave occurs when the crest tumbles down the face of the wave.  As the tide gets lower and the sandbank that the waves are breaking on becomes shallower, this type of wave will form tunnels or “tubes”.

Surging wave

This wave may never actually break as it approaches the water’s edge.  This is because it is very deep beneath the wave and the wave does not lose speed or gain height.

Collapsing

Collapsing waves are a cross between plunging and surging, in which the crest never fully breaks, yet the bottom face of the wave gets steeper and collapses, resulting in foam


TOP 10 SURF SAFETY TIPS

  • Always swim or surf at a beach patrolled by lifesavers or lifeguards.
  • Swim between the red and yellow flags.  They mark the safest areas to swim.
  • Avoid swimming alone or unsupervised.
  • Read the signs.  If a beach is closed, don’t swim there.
  • If you are unsure of the surf conditions ask a lifeguard or lifesaver.
  • Don’t swim directly after a meal.
  • Don’t swim under the influence of alcohol or drugs.
  • Don’t run or dive in the water, always check the conditions, as they might have changed.
  • If you get in trouble in the water, don’t panic -raise one arm up and float until help arrives.
  • Float with a rip current or undertow, don’t swim against it.


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© Porthtowan S.L.S.C 2011.