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From: Craig Jungers <crjungers_at_gmail.com>
subject: [Paddlewise] "Sneaker Waves"
Date: Fri, 18 Jan 2008 11:31:12 -0800
I was over in Seattle picking up doodads for the mutha-ship and managed to
get a Latitude 38 magazine from San Francisco. All Bay Area and most
cruising sailors are familiar with Lat 38 but kayakers may not be. It's
geared to the Bay Area sailors and to the cruisers mainly in Baja California
and the articles are usually well written and authoritative by people who
have not only "been there" but are very likely "out there" right now. I
should know... I was one of them back in the 80s. <grin>

This issue (current for this month) had a short discussion on "sneaker
waves" in the Letters section that I thought would be appropriate for
paddlers.

Sneaker waves have been around forever. I've had a few friends get hit by
them. They occur along the Pacific coast of North America mainly in the
winter and spring months and seem to be caused by long-period waves
generated by storms in the western North Pacific Ocean. These long-period
waves behave somewhat like Tsunamis in that they carry an enormous amount of
energy and they are almost unnoticed in deep water but release their energy
in shoal water or around rocks.They are not well understood yet and there is
a certain amount  of controversy regarding what, exactly, they are. One
thing is fairly obvious though... they are very dangerous to boaters in
shallow coastal waters.

And that is where paddlers come in.

Sailboaters and other coastal cruisers generally don't get into shallow
water until they are approaching land either to enter a harbor or anchorage
or are in the process of departing. Kayaks, on the other hand, spend a lot
of time in shallow water because that's where almost all the fun is.

Basically what paddlers on the west coast of North America need to be aware
of is wave period. Check offshore wave-rider buoys and if the swell period
is greater than about 5 minutes be very cautious when paddling in shallow
water exposed to the open ocean. If the swell period rises to 14 minutes be
on constant alert.

A story to illustrate the nature of these is about cruising friends of mine
who were approaching an anchorage north of Morro Bay. It was getting dark
and the seas were flat calm with a long rolling swell. As they were motoring
in they passed a well-marked rock (giving it what they thought was plenty of
room) when their boat was suddenly picked up by a huge sea and washed over
that rock. This was in a 38-foot, 25,000 pound cruising sailboat!!

No one was injured but a lot of water made its way below and they spent an
extra week in Morro Bay drying things out. It also resulted in a rule we all
subsequently followed: all companionways, hatches, and portlights are closed
and dogged down tight and all crew on deck wears PFDs and are clipped into
the lifelines.

As I said earlier, there is some controversy as to the exact nature of these
waves. This is partly because there is often only one wave in what otherwise
might only be relatively calm water and ocean scientists don't like the idea
of one wave rising up from nowhere. Nevertheless, "sneaker waves" are well
documented even if they are not well understood. If you paddle the open
ocean along the west coast of North American (and, for all I know, any
coastline open to a fetch that extends thousands of miles) watch for
long-period swells and be ready any time you are in shallow water or around
reefs and rocks.


Craig Jungers
Moses Lake, WA
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From: Dave Kruger <kdruger_at_pacifier.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sat, 19 Jan 2008 00:14:25 -0800
Craig Jungers wrote:

> Basically what paddlers on the west coast of North America need to be aware
> of is wave period. Check offshore wave-rider buoys and if the swell period
> is greater than about 5 minutes be very cautious when paddling in shallow
> water exposed to the open ocean. If the swell period rises to 14 minutes be
> on constant alert.

You mean "5 seconds" and "14 seconds," yes, Craig?

> As I said earlier, there is some controversy as to the exact nature of these
> waves. This is partly because there is often only one wave in what otherwise
> might only be relatively calm water and ocean scientists don't like the idea
> of one wave rising up from nowhere.

I've always heard sneakers explained as the result of constructive 
interference of two waves from slightly different sources, such that a 
single wave (the result of two combined) "jumps" out of the blue.  However, 
there is a more erudite discussion of possible causes here, under "rogue 
waves:"  http://en.wikipedia.org/wiki/Freak_wave

In addition, some feel a wave like Craig describes may be a "soliton:" 
http://en.wikipedia.org/wiki/Soliton  [Googling up "soliton" will lead you 
to lots of very deep stuff -- solitons are thought to be a branch of 
nonlinear science.]

Take your pick.  Stuff like this is hard to pin down, scientifically, 
because it is hard to reproduce in a laboratory (wave lab).

-- 
Dave Kruger
Astoria, OR
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From: Craig Jungers <crjungers_at_gmail.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sat, 19 Jan 2008 09:17:00 -0800
On Jan 19, 2008 12:14 AM, Dave Kruger <kdruger_at_pacifier.com> wrote:

>
> You mean "5 seconds" and "14 seconds," yes, Craig?


Oops... yes... seconds not minutes. Ack!

I've always heard sneakers explained as the result of constructive
> interference of two waves from slightly different sources, such that a
> single wave (the result of two combined) "jumps" out of the blue.
>  However,
> there is a more erudite discussion of possible causes here, under "rogue
> waves:"  http://en.wikipedia.org/wiki/Freak_wave


Various groups associated with the ocean have their own interpretations of
sneaker waves (and their own nomenclature, too). A "rogue" wave on the ocean
is very likely a combination of  two (or more) heavy seas plus upwellings or
currents. But that's out in the open ocean and generally in the very rough
open ocean. One of the characteristics of "sneaker" waves is that they are
unnoticed in deep water but potentially catastrophic when the water suddenly
shoals.

But it's possible that a combination of two long-period swells could be the
cause of the single "sneaker" wave. This would help explain the way "sneaker
waves" appear out of the blue in what is a calm ocean (as described by
people who have been snuck-up upon). Long-period swells may not be obvious
on a day with no wind. <http://en.wikipedia.org/wiki/Freak_wave>

>
> Take your pick.  Stuff like this is hard to pin down, scientifically,
> because it is hard to reproduce in a laboratory (wave lab).


I've always been attracted to "non linear science" because there is just so
much of it around. Especially in fluids. Chaotic behavior is always more
interesting to me than predictable behavior. :)

Regardless of the cause, the name, or the science; there are unpredictably
large waves that seem to be associated with long-period (5 seconds and over)
swells in the winter and spring months. If you paddle in shallow watter
exposed to the open ocean you should check for swell periods on the offshore
wave rider buoys and behave in whatever you believe is your best interest.

One question I had is why so many of these "sneaker" wave problems seem to
occur in what is described as calm conditions. Long-period swells must also
occur on days when the wind blows, too. But maybe boaters tend to stay
farther from shoaling water when it's obviously rough.

Didja launch the bartender yet?


Craig Jungers
Moses Lake, WA
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From: Dave Kruger <kdruger_at_pacifier.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sat, 19 Jan 2008 10:33:52 -0800
Craig Jungers wrote:

> Regardless of the cause, the name, or the science; there are 
> unpredictably large waves that seem to be associated with long-period (5 
> seconds and over) swells in the winter and spring months. If you paddle 
> in shallow watter exposed to the open ocean you should check for swell 
> periods on the offshore wave rider buoys and behave in whatever you 
> believe is your best interest.

Craig, I'd boost that 5 seconds to 8 to 12.  The wave period is pretty much 
always above 7-8 around here and maybe 50% of the time over 10-12.  Wave 
energy scales as the cube of the period (more or less), so small changes in 
period can generate big changes in wave intensity.

> One question I had is why so many of these "sneaker" wave problems seem 
> to occur in what is described as calm conditions. Long-period swells 
> must also occur on days when the wind blows, too. But maybe boaters tend 
> to stay farther from shoaling water when it's obviously rough.

I think that is the case:  it is association and perception, not 
"objective" observation.

> Didja launch the bartender yet?

Very close. Down to last minute outfitting, fueling, etc.  More photos soon 
on this site (go to the bottom):
http://www.pbase.com/bartenderdave/204_bartender_part_iii

-- 
Dave Kruger
Astoria, OR
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From: Craig Jungers <crjungers_at_gmail.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sat, 19 Jan 2008 17:01:17 -0800
On Jan 19, 2008 10:33 AM, Dave Kruger <kdruger_at_pacifier.com> wrote:

>
> Craig, I'd boost that 5 seconds to 8 to 12.  The wave period is pretty
> much
> always above 7-8 around here and maybe 50% of the time over 10-12.  Wave
> energy scales as the cube of the period (more or less), so small changes
> in
> period can generate big changes in wave intensity.


Ya... that seems right to me... certainly around 14 seconds period has been
documented to produce at least one sneaker wave.


>
> Very close. Down to last minute outfitting, fueling, etc.  More photos
> soon
> on this site (go to the bottom):
> http://www.pbase.com/bartenderdave/204_bartender_part_iii


You've done an excellent job on that boat and it really shows. I can't wait
to see it in person. :)

Craig Jungers
Moses Lake, WA
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From: Darryl <Darryl.Johnson_at_sympatico.ca>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sat, 19 Jan 2008 20:52:30 -0500
> > Very close. Down to last minute outfitting, fueling, etc.  More photos
> > soon
> > on this site (go to the bottom):
> > http://www.pbase.com/bartenderdave/204_bartender_part_iii
> 
> 
> You've done an excellent job on that boat and it really shows. I can't wait
> to see it in person. :)
> 
> Craig Jungers
> Moses Lake, WA

I'm anxiously waiting for my personal invitation to come onboard for 
the maiden voyage. As, I'm sure, everyone else on the list is as 
well.

I sent my drysuit out for dry-cleaning and pressing. I do want to 
look sharp for the occasion! (Does one wear black or white tie with a 
drysuit?)

-- 
  Darryl
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From: Craig Jungers <crjungers_at_gmail.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sat, 19 Jan 2008 18:09:39 -0800
On Jan 19, 2008 5:52 PM, Darryl <Darryl.Johnson_at_sympatico.ca> wrote:

>
> I sent my drysuit out for dry-cleaning and pressing. I do want to
> look sharp for the occasion! (Does one wear black or white tie with a
> drysuit?)
>

I'm a little rusty on the formalities of formal wear... but I'd guess that a
black tie so it doesn't clash with your black kayak booties. :)

Knowing Kruger I think anyone who shows up should be prepared to be put to
work! :)

Craig Jungers
Moses Lake, WA
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From: Gary J. MacDonald <garyj_at_rogers.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sat, 19 Jan 2008 21:38:23 -0500
I wear a multi-coloured bungie with mine!

Darryl wrote:
> I'm anxiously waiting for my personal invitation to come onboard for 
> the maiden voyage. As, I'm sure, everyone else on the list is as 
> well.
>
> I sent my drysuit out for dry-cleaning and pressing. I do want to 
> look sharp for the occasion! (Does one wear black or white tie with a 
> drysuit?)
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From: Dave Kruger <kdruger_at_pacifier.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sat, 19 Jan 2008 19:57:51 -0800
Darryl wrote:
>>> Very close. Down to last minute outfitting, fueling, etc. 

> I'm anxiously waiting for my personal invitation to come onboard for 
> the maiden voyage. As, I'm sure, everyone else on the list is as 
> well.
> 
> I sent my drysuit out for dry-cleaning and pressing. I do want to 
> look sharp for the occasion! (Does one wear black or white tie with a 
> drysuit?)

Strictly neoprene.  This is a middle-class boat.  Craig's is high-class.

-- 
Dave Kruger
Astoria, OR
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From: Craig Jungers <crjungers_at_gmail.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sat, 19 Jan 2008 21:38:20 -0800
On Jan 19, 2008 7:57 PM, Dave Kruger <kdruger_at_pacifier.com> wrote:

>
> Strictly neoprene.  This is a middle-class boat.  Craig's is high-class.
>

So that's what ya call a 1974 boat that cost $3500. I was wonderin'.


Craig Jungers
High Class in Moses Lake, WA
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From: Bob Carter <revkayak_at_aptalaska.net>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sat, 19 Jan 2008 22:11:05 -0900
> So that's what ya call a 1974 boat that cost $3500. I was wonderin'.
> 
> 
> Craig Jungers

A hole in the water you pour money into.
Been there done that!

Bob
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From: Craig Jungers <crjungers_at_gmail.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sun, 20 Jan 2008 07:31:14 -0800
On Jan 19, 2008 11:11 PM, Bob Carter <revkayak_at_aptalaska.net> wrote:

>
> A hole in the water you pour money into.
> Been there done that!
>

I dunno about you but I keep my boat on a trailer. That way the money
filters out at the bottom. :)


Craig Jungers
Crawling around under the  mutha-ship in...
Moses Lake, WA
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From: Gary J. MacDonald <garyj_at_rogers.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sun, 20 Jan 2008 12:13:50 -0500
Craig Jungers wrote:
> On Jan 19, 2008 11:11 PM, Bob Carter <revkayak_at_aptalaska.net> wrote:
>
>   
>> A hole in the water you pour money into.
>> Been there done that!
> I dunno about you but I keep my boat on a trailer. That way the money
> filters out at the bottom. :)
Maybe you should put a tarp *under* the boat to catch the money and run 
it through again?
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From: Matt Broze <marinerkayaks_at_msn.com>
subject: Re: [Paddlewise] "Sneaker Waves"
Date: Sun, 20 Jan 2008 16:36:19 -0800
There is a lot of energy in long waves. This energy can be concentrated in
several ways to create sneaker waves. Even if all the waves are uniform in
size and have arrived at the shore from a single distant storm, the
underwater topography off shore can bend the waves in such a way to focus
them onto an area. If that area is also shallow the slowing of the wave
front can create an even higher amplitude wave at the shallows. Combine that
with the focused waves crossing each other right at the shallows at the
right time and a much larger wave can result because the two wave amplitudes
are additive. A jetty (I forget where--somewhere on the west coast I think,
maybe CA) had stood for years until it was battered apart when long low
waves arrived from just the right direction to get them focused on the jetty
by the underwater topography further out. Recall that longer waves "feel the
bottom a lot deeper than shorter waves so this focusing of even one wave
trains energy can also happen out in somewhat deeper water than with shorter
waves.

If you have long waves coming from two or more different storms arriving at
the same time, out of phase, and from different directions you could get
even higher amplitude waves where the crests all add together at the same
time. If this large hump of water from combined wave crests also happened to
be shoaling at the same time they came together it will jump up far higher.
It would be rare to all come together at once but it happens and if you are
paddling there at the same time you will probably be lucky if all you have
to do is clean your shorts afterward.

My understanding is that a "Wave of Translation" or soliton is a wave that
moves water from one place to another. The most common one we are likely to
see clearly is the soup wave that runs up the beach after a wave enters
shallow enough water to destroy its normal orbital wave motion and break. If
you watch this for awhile you will also see waves formed in this near shore
zone that aren't breaking and aren't soups, but well up in a single smooth
steep wave (often somewhat crossing the breaking soups). Other instances of
Waves of translation could be the waves at the front of a tidal flow
entering a narrowing channel that focuses the energy such as the Bay of
Fundy, Turnigan Arm in AK, the mouth of the Amazon and several other river
mouths abound the world (known as tidal bores). The one example Russell
noticed from the suddenly stopped barge (my guess it grounded on shallows is
why it stopped) and wrote about can also be seen by kayakers entering very
shallow water on a dead calm day. The kayaks wake changes its usually
constant angle and the angle swings forward (making it more obtuse) until it
is going nearly straight out from the bow (or possibly just in front of the
bow) at each side of the bow. Try looking for it the next time you are
paddling fast into uniformly deep, roughly 6" to 8" deep, shallow water on a
calm day. Once I read about and knew what to look for I've noticed it many
times.

Matt Broze
www.marinerkayaks.com  
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