September 2017
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Getting Along with Eddy

Paddlers on quiet backwaters and freshwater lakes may never run into Eddy
but anyone who navigates boats in areas of current soon learns to develop a
respect and admiration for the Eddy. In waters beset by currents such as
rivers, estuaries and archipelagoes, the eddy can be your friend or your
enemy. And while an eddy can be predicatable, they are often mercurial in
both direction and speed. If you want to paddle your boat where there is
current then you need to learn how to recognize and deal with Eddy.

An eddy can be defined as an area of differing current in a region of
currents. Eddies might run counter to the main current, across the main
current, or even in a circular pattern (whirlpool). They are caused by the
hydraulic mechanism of moving water as it encounters obstructions to its
path and are most often found in areas where that are many such
obstructions. Virtually all but the slowest river has eddies along the
shoreline but deep ocean water rarely has them. An eddy is a creature of
current; of water movement and where there is no water movement there can be
no eddies.

The border between the main current and an eddy is called an "eddy line" and
is often seen as a defined separation between currents. Because the eddy has
a different direction and speed from the main current, it often can be
recognized by a differing pattern of surface waves. But most often from the
vantage point of a paddler you will recognize the eddy line as a line -
often marked with foam in salt water - in which the water on one side can be
seen to be moving in a different direction and speed than the water on the
other side.

This difference in direction and speed is what causes the greatest grief to
a paddler. If the difference is large enough then crossing an eddy line can
result in a capsize if the kayaker is not paying attention.

Eddies caused by river current - or any current of constant direction - are
relatively predictable. They typically reside downstream of any obstruction.
A large rock will have an eddy behind it and an eddy line to cross to get
into the eddy. A point of land or a shallow gravel bar extending into the
river's flow will have an eddy (or even multiple eddies) downstream. The key
to these eddies is the word "downstream". Eddies always lay downstream from
whatever obstruction or underwater mechanism causes them.

Rivers and sloughs often have a shore eddy which results from the friction
of the water against the irregular surface of the shoreline. River kayakers
often "eddy out" into these along-shore eddies which can offer protection
from the main river current passing only inches away. The best and widest of
these eddies are those which lay just downstream from a rock or a point or
even some grass growing into the river.

Tidal estuaries and bays subject to tidal ranges can also have an
along-shore eddy that can be used to advantage by a paddler. But while a
river's current is relatively stable (at least directionally) the tidal
current flows one direction for a while and then turns around and flows in
the opposite direction. To determine the current direction a paddler often
has to resort to checking how water plants are laying in the water or
watching for wake patterns on rocks or buoys.

In order to best deal with an eddy it's important to have some understanding
of the mechanisms which cause them. Water is, for all practical purposes,
uncompressable so that a stream of water flowing against an unmovable object
will tend to "pile up" onto that object. A point of land extending into the
current stream and presenting a smooth face to that stream will have no
eddies on the upstream side. But downstream, where the water can't quite
make the hard turn to get behind the point, there will be an area where the
flow must go contrary to the current in order to maintain its level. This
downstream area is where you will encounter an eddy; the stronger the
current and the more prominent the point of land, the faster the eddy.

Rule: Don't go looking for an eddy on the upstream side of an island with no
(or few) breaks in its shoreline. You are likely, instead, to find even
faster current and even rips.

Crossing an eddy line is a tricky maneuver because the water in the current
flow sees your boat as just another obstruction and piles against it. A
capsize in an eddy typically is in the direction of the main current flow
because the eddy current has heaped up onto the downstream side of the boat
and flipped it over. The way to deal with an eddy line is to tip your boat
upstream to the main current before you cross the eddy line and brace
upstream with your paddle.  Then you can rudder your bow (with a rudder or
the paddle that you are using to brace) around and into the eddy. Once your
boat is entirely across the eddy line you can maneuver normally.

Rule: When crossing an eddy line show the current in the eddy the bottom of
your boat.

An eddy which is caused by an obstruction into a particularly violent
current flow can be a hazard all by itself. The hydraulics which created the
eddy are seldom static and there can be upflows, cross currents and even
whirlpools in the eddy which can cause an inattentive paddler grief. In
general if you stay closer to the shoreline you will be in a region of
calmer water but as you move closer to the end of the point of land that
generated the eddy the water will become more unstable.

Passages between islands in a bay beset with tidal currents is an exercise
in planning and caution. If you are paddling with the current It is often
best to leave the relative safety of a near-shore position in order to avoid
the often-violent water of a point which you must go around. In many cases
the upstream side of the point has been sheared clean of any along-shore
roughness which could be relied upon to provide an eddy. Instead you will be
paddling in the water "piled up" onto that shoreline by the current. This
can be relied upon to give you a fast ride along the shore and right into
the most likely spot for rips and counter-currents. If you paddle off-shore
a ways (often a half-mile off) you may avoid the worst of the mayhem. You
can then maneuver back near shore once you are past the point.

If you are traveling against the current and close to shore you will find
yourself in an eddy as you approach that same point. The best rule is to lay
as close to shore as practicable - often only a paddle length away - in
order to take advantage of the eddy. This position also puts you in the best
position to "eddy out" (if possible) so you can get out and scout the water
off the point itself. At the point itself you will encounter the full force
of the current. Again, a safer route might be to leave the eddy well before
the point and just battle the current offshore until you can safely find
another eddy to travel within or cross the channel and find an eddy on the
opposite shore to ride.

Rule: If you use an eddy to help you move upstream stay as close to the
shore as possible; often a paddle length off. But be ready to leave that
position and move well offshore to avoid hazards or move across the channel
and continue upstream in that eddy.

When entering the main current stream from a position inside the eddy you
are faced with essentially the same problem you faced when you entered the
eddy. The water in the main current will see your boat as an obstruction and
pile up against it. The classic maneuver is to point the bow of your boat
slightly upstream of the main current flow, tilt your boat downstream (show
the current flow your bottom) and rudder the boat around as it enters the
stream. It is also possible to enter from the point where the eddy begins;
usually well downstream from the obstruction that created the eddy and in a
counter-current that is not as fast. In this case you can often simply
paddle vigorously out into the current stream with the bow pointed mostly
downstream while being ready to brace upstream.


Rips are a form of eddy that are characterized by a clearly defined
difference in wave pattern and current speed. In some locations and under
certain conditions rips can approach the severity of Class IV or V river
rapids and so should always be treated with caution. Charts often indicate
which areas are most subject to rips and should be used for planning trips
through these areas. Do not confuse the term "rip" with the term "rip
current". A rip in a tidal area can be a serious hazard for a kayaker.

Small rips are common in areas beset with current. Anyone paddling the
inland passages of Puget Sound in Washington or the waters of British
Columbia will paddle through countless areas where the traditional rip
triangular wave pattern exists. But heavy rips can be dangerous and even
deadly especially when combined with high winds blowing against the current
flow. Paddlers entering areas where there are passages between islands
subject to tidal currents should familiarize themselves with the appropriate
charts and learn where these rips are likely to be found.

Dealing with areas of heavy and dangerous rips can be done safely if you
follow a few rules:

1. Plan your trip so that any heavy rip areas are traversed at a time of
slack water or very nearly slack water. One should also remember that slack
water often lasts only about 10 or 15 minutes.

2. Plan your trip to take advantage of the lowest tidal range in the month.
Tidal ranges are not always the same every day so use tide and current
tables for the region you plan to paddle in and plan accordingly.

3. Have backup plans if the wind and currents make your primary plan
dangerous and remember that a wind with the current becomes a wind against
the current at the change of tide.

4. Keep in mind that simply turning back may not be an option once you are
committed. Think about an escape route and brief everyone about it.

5. Heavy rips are not as visible from upstream (just as breakers are not as
easy to spot from the seaward side). Watch for spray and listen for noise.
Heavy rips make noise.

6. You are safest crossing a channel downcurrent of a heavy rip; in the
greatest danger crossing upcurrent of the rip.

7. Equip yourself properly for the conditions including possible immersion
into cold water.


Whirlpools have frightened mariners for thousands of years but in 35 years
of running small and large boats I've seen only relatively gentle ones.
Those I have encountered I could simply paddle out of by treating the edge
of the whirlpool as an eddy line and dealing with it accordingly. Dangerous
whirlpools are to be found in narrow passages subject to extreme tidal
ranges such as a few infamous channels in the inland waters of British
Columbia and Alaska. Like the doctor told the man who broke his arm in two
places: stay away from those places. At least when the current is running
fast. Many of these areas of tidal races can be navigated safely at slack
water. Just be quick.

Dealing with Eddy is always interesting because his moods change frequently.
The best way to learn to handle eddies (and moving water in general) is to
take a course in whitewater kayaking from your nearest kayak shop. The most
interesting places to paddle are often those subject to currents and eddies.

Craig Jungers
Royal City, WA