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Rouge waves

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  • Phil
    There are several causes of what some people would term rouge waves. A wave pattern that is in the process of having another wave pattern superimposed on it by
    Message 1 of 14 , Aug 30, 2004
      There are several causes of what some people would term rouge waves. A
      wave pattern that is in the process of having another wave pattern
      superimposed on it by a shift in the wind can create rogue waves.
      Another cause is shallow patches of sea bottom. As the wave energy
      comes from deep water and the energy stacks up on the shallow bottom it can
      create some spectacular waves. And there are many places hundreds of miles
      offshore where the bottom gets very shallow.
      One place where there can be some real killer waves is Cortez Bank. It
      is off the Calif coast. Waves can reach more than 70 feet in height and
      break.
      Phil
    • hal
      ... Where is that in relation to coastal cities I can find on a map? (IE Ventura, Monterey) hal
      Message 2 of 14 , Aug 30, 2004
        On Aug 30, 2004, at 3:58 PM, Phil wrote:
        >
        > One place where there can be some real killer waves is Cortez
        > Bank. It
        > is off the Calif coast. Waves can reach more than 70 feet in height and
        > break.
        > Phil

        Where is that in relation to coastal cities I can find on a map? (IE
        Ventura, Monterey)

        hal
      • boblq
        ... Apparently one important cause is interactions with currents. Currents contain huge amounts of energy (just think of the volume of water moving at a few
        Message 3 of 14 , Aug 30, 2004
          On Monday 30 August 2004 02:58 pm, Phil wrote:
          > There are several causes of what some people would term rouge waves. A
          > wave pattern that is in the process of having another wave pattern
          > superimposed on it by a shift in the wind can create rogue waves.
          > Another cause is shallow patches of sea bottom. As the wave energy
          > comes from deep water and the energy stacks up on the shallow bottom it can
          > create some spectacular waves. And there are many places hundreds of miles
          > offshore where the bottom gets very shallow.

          Apparently one important cause is interactions with currents.
          Currents contain huge amounts of energy (just think of the
          volume of water moving at a few knots) and if an instability
          extracts energy from the directed flow into a wave then
          that wave can be huge. I note that these are something
          actually quite different from the effect of a large swell
          being focused by the shape of the ocean bottom. These
          beasts which derive energy from a current can be far larger
          than any ordinary focussing effect will achieve.

          To get a handle on this think of what causes an ordinary
          wave, i.e. wind blowing across a water surface. The boundary
          is unstable and energy is derived from the wind. A wave grows.
          Now think of the Japan Current or Gulf Stream (each far larger
          than the Mississippi River) flowing along an interface and
          imagine how much more energy can be transfered. A wind
          driven wave triggers this process but the current provides
          the raw energy need to drive the wave to huge size.

          But there may be another nonlinear phenomena which
          enables one wave to extract energy from many other waves
          growing to huge size in the process. Some such process
          seems needed to explain waves in the open ocean far from
          large currents.

          No real theory exists for any of this yet and the observations
          (satellite data) are in their infancy. But this much is certain.
          Rogue waves are real and not just a product of some ancient
          mariners feverish dreams.

          > One place where there can be some real killer waves is Cortez Bank. It
          > is off the Calif coast. Waves can reach more than 70 feet in height and
          > break.

          There is a place of the coast of Baja near Ensenada called Todos Santos
          where waves are often in the 50 ft range and probably go to 70 ft on
          occasion. There are probably several dozen such spots (at least) around
          the world. But they are not really "rogue" waves. They are rather
          examples of the bottom topography acting to focus wave energy
          and as such are actually fairly predictable.

          boblq
        • Roger Derby
          Actually, a Fourier transform will give insight into how many regular waves can combine to create a pulse. Roger derbyrm@starband.net
          Message 4 of 14 , Aug 31, 2004
            Actually, a Fourier transform will give insight into how many regular waves
            can combine to create a "pulse."

            Roger
            derbyrm@...
            http://derbyrm.mystarband.net/default.htm

            ----- Original Message -----
            From: "boblq" <boblq@...>

            <snip>
            > No real theory exists for any of this yet and the observations
            > (satellite data) are in their infancy. But this much is certain.
            > Rogue waves are real and not just a product of some ancient
            > mariners feverish dreams.
          • Bruce Hallman
            ... I guess that is what happened in this case, quoting from the article: [Mr.] Wolf said swells pick up at Bodega Rock near where the accident happened
            Message 5 of 14 , Aug 31, 2004
              > the world. But they are not really "rogue" waves. They are rather
              > examples of the bottom topography acting to focus wave energy
              > and as such are actually fairly predictable.
              >
              > boblq

              I guess that is what happened in this case, quoting from the
              article:

              "[Mr.] Wolf said swells pick up at Bodega Rock near where
              the accident happened "

              Made worse, I think because of the dense fog.

              Still, snapping in with a lifeline, (sort of like wearing a seatbelt
              in a car) would probably be tolerable and worthwhile. 99% of
              the time in a boat you are stationary anyway.
            • David Ryan
              Bruce, If you want to see some HUGE breakers (but not actual rogue waves) take a drive down the coast next Winter to a spot called Maverick s. Jeff Clark s
              Message 6 of 14 , Aug 31, 2004
                Bruce,

                If you want to see some HUGE breakers (but not actual rogue waves) take
                a drive down the coast next Winter to a spot called Maverick's.

                Jeff Clark's pioneering efforts at this spot nearly singlehandedly
                revived interest big wave surfing, which has proven to be the single
                most commercially promotable aspect of the sport. Lots of startling
                photos and videos at:

                http://www.mavsurfer.com

                These guys are way, way out of my league. The biggest thing I've ever
                ridden was a 15-20 foot face, and I was scare to death.

                YIBB,

                David

                On Tuesday, August 31, 2004, at 10:36 AM, Bruce Hallman wrote:

                >> the world. But they are not really "rogue" waves. They are rather
                >> examples of the bottom topography acting to focus wave energy
                >> and as such are actually fairly predictable.
                >>
                >> boblq
                >
                > I guess that is what happened in this case, quoting from the
                > article:
                >
                > "[Mr.] Wolf said swells pick up at Bodega Rock near where
                > the accident happened "
                >
                > Made worse, I think because of the dense fog.
                >
                > Still, snapping in with a lifeline, (sort of like wearing a seatbelt
                > in a car) would probably be tolerable and worthwhile. 99% of
                > the time in a boat you are stationary anyway.
                >
                >
                >
                > Bolger rules!!!
                > - no cursing, flaming, trolling, spamming, or flogging dead horses
                > - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
                > - Pls add your comments at the TOP, SIGN your posts, and snip away
                > - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930,
                > Fax: (978) 282-1349
                > - Unsubscribe: bolger-unsubscribe@yahoogroups.com
                > - Open discussion: bolger_coffee_lounge-subscribe@yahoogroups.com
                > Yahoo! Groups Links
                >
                >
                >
                >
                >
              • Nels
                ... Lots of startling ... ever ... I was at the Maui location once when the surf was up to about 50 footers. You watch from the cliffs above where there is a
                Message 7 of 14 , Aug 31, 2004
                  --- In bolger@yahoogroups.com, David Ryan <david@c...> wrote:
                  > Bruce,
                  >
                  Lots of startling
                  > photos and videos at:
                  >
                  > http://www.mavsurfer.com
                  >
                  > These guys are way, way out of my league. The biggest thing I've
                  ever
                  > ridden was a 15-20 foot face, and I was scare to death.
                  >
                  > YIBB,
                  >
                  > David
                  >
                  I was at the Maui location once when the surf was up to about 50
                  footers. You watch from the cliffs above where there is a funneling
                  affect when the winds are from the north - and there is this tiny
                  beach below and huge cliffs all around. Because of the height, you
                  don't appreciate the sheer size of the waves until you look through
                  binocs. These guys are totally insane! Not far from there and
                  offshore they are tearing around on wind surfers doing 360's in the
                  air, and reaching speeds beyond belief. Rather other-worldly to say
                  the least!

                  Cheers, Nels
                • Jerry
                  Cortez Bank is 105 miles west of San Diego. Lots of pictures, do a Google search... -Jerry
                  Message 8 of 14 , Aug 31, 2004
                    Cortez Bank is 105 miles west of San Diego. Lots of pictures, do a
                    Google search...
                    -Jerry
                  • David Ryan
                    That sounds like you were at a spot called Jaws. I think sailboarders were the first to take it on because they were the only guys who had the speed to get
                    Message 9 of 14 , Aug 31, 2004
                      That sounds like you were at a spot called Jaws.

                      I think sailboarders were the first to take it on because they were the
                      only guys who had the speed to get into such big waves (beyond a
                      certain size they're just too fast to paddle into.) The one day someone
                      had the bright idea to use a jetski as a tow-in vehicle. I am somewhat
                      ambivalent about aesthetics mechanized surfing, but there's no denying
                      what they're doing it spectacular. Somewhere on the MavSurfer.com
                      website there's a link to a video of a guy riding a 70 foot wave at
                      Jaws.

                      Fortunately these monsters are quite predictable, both in timing and
                      location, so they're no real threat to mariners. But here's an
                      interesting surfing phenomenon. On any given day with a given average
                      sized set wave you will also have sets come through that are 50%-100%
                      larger, and break further out. These "clean up sets" come infrequently
                      enough that most people are caught closer to the beach waiting for the
                      day's average sized waves. (They are named clean up sets because the
                      effect is that they clean everyone out of the line up.) When the
                      average surf is 3 feet it's no big deal, because when you see them
                      coming you can paddle out to meet them. When it's 10 feet it can be
                      quite hair-raising, because the relative distances are increase, and
                      sometime you're not fast enough to paddle out and over them before they
                      break. Of course the bigger waves break much hard too, so getting
                      "caught inside" is much more unpleasant. Can't imagine what it would be
                      like to be out on a 35 foot day and then see a set of 50 footers coming
                      over the horizon.

                      -David


                      On Tuesday, August 31, 2004, at 11:22 AM, Nels wrote:

                      > I was at the Maui location once when the surf was up to about 50
                      > footers. You watch from the cliffs above where there is a funneling
                      > affect when the winds are from the north - and there is this tiny
                      > beach below and huge cliffs all around. Because of the height, you
                      > don't appreciate the sheer size of the waves until you look through
                      > binocs. These guys are totally insane! Not far from there and
                      > offshore they are tearing around on wind surfers doing 360's in the
                      > air, and reaching speeds beyond belief. Rather other-worldly to say
                      > the least!
                      >
                      > Cheers, Nels
                      >
                      >
                      >
                      >
                      > Bolger rules!!!
                      > - no cursing, flaming, trolling, spamming, or flogging dead horses
                      > - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
                      > - Pls add your comments at the TOP, SIGN your posts, and snip away
                      > - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930,
                      > Fax: (978) 282-1349
                      > - Unsubscribe: bolger-unsubscribe@yahoogroups.com
                      > - Open discussion: bolger_coffee_lounge-subscribe@yahoogroups.com
                      > Yahoo! Groups Links
                      >
                      >
                      >
                      >
                      >
                    • boblq
                      ... Not really. The problem as now established by observation is that large waves occur much more frequently then can be accounted for by the random linear
                      Message 10 of 14 , Aug 31, 2004
                        On Tuesday 31 August 2004 03:26 am, Roger Derby wrote:
                        > Actually, a Fourier transform will give insight into how many regular waves
                        > can combine to create a "pulse."
                        >
                        > Roger
                        > derbyrm@...
                        > http://derbyrm.mystarband.net/default.htm

                        Not really. The problem as now established
                        by observation is that large waves occur
                        much more frequently then can be accounted
                        for by the random linear supposition of small
                        waves.

                        Once a large nonlinear wave is formed one can
                        certainly decompose it with a Fourier transform
                        but this does not much real insight into the processes
                        that formed it.

                        The problem for boat design is different. What
                        do we do about a rare but catastrophic event?
                        Designing a boat to survive a rogue wave (or
                        even a wave of rouge, chuckle) may make it perform
                        much worse almost all of the rest of the time ...

                        boblq
                      • Roger Derby
                        Honestly I ve never gotten much mileage from the Fourier Transform. Too much work before computers, but the concept is enlightening. If random
                        Message 11 of 14 , Aug 31, 2004
                          Honestly I've never gotten much mileage from the Fourier Transform. Too
                          much work before computers, but the concept is enlightening. If "random
                          superposition" won't do it, might there be some unidentified driving force?

                          As to "Seaworthy Offshore Sailboats," John Vigor wrote a very interesting
                          book by that title. As part of each topic/chapter, he instructs us to
                          "Think upside down." After we address the question of self-righting and
                          pumping dry, we then need spare spars for jury rigging, etc. and we need to
                          insure that the tools and spares have remained with the boat.

                          The Chebacco I'm building will not be a seaworthy offshore boat. I'm
                          looking for a trailer sailer with which to explore the rivers and lakes here
                          in the Midwest. The "cabin" is devolving into a hard dodger to keep off the
                          sun and provide some privacy for the head. More of a campsite or scruffy
                          motel room than a home away from home. Birdwatcher certainly has a lot to
                          recommend it, but one sits on the bottom and Chebacco is prettier.

                          A life line is a good thing. The Sunfish sailed off without me one time and
                          since then I've lashed the painter to my belt for most sails. I figure I'll
                          make a fine sea anchor to keep it within swimming distance.

                          Roger
                          derbyrm@...
                          http://derbyrm.mystarband.net/default.htm

                          ----- Original Message -----
                          From: "boblq" <boblq@...>


                          > On Tuesday 31 August 2004 03:26 am, Roger Derby wrote:
                          > > Actually, a Fourier transform will give insight into how many
                          > > regular waves can combine to create a "pulse."
                          >
                          > Not really. The problem as now established
                          > by observation is that large waves occur
                          > much more frequently then can be accounted
                          > for by the random linear supposition of small
                          > waves.
                          >
                          > Once a large nonlinear wave is formed one can
                          > certainly decompose it with a Fourier transform
                          > but this does not much real insight into the processes
                          > that formed it.
                          >
                          > The problem for boat design is different. What
                          > do we do about a rare but catastrophic event?
                          > Designing a boat to survive a rogue wave (or
                          > even a wave of rouge, chuckle) may make it perform
                          > much worse almost all of the rest of the time ...
                        • Jerry
                          Here s an article that adds support for the lifeline idea. Add boarding features to that short list of disaster prevention measures and this man s day would
                          Message 12 of 14 , Aug 31, 2004
                            Here's an article that adds support for the lifeline idea. Add
                            boarding features to that short list of disaster prevention measures
                            and this man's day would not have turned out quite so bad.

                            -Jerry
                            SF Pelican 12

                            <http://www.baycrossings.com/Archives/2003/10_November/harbor_bay_ferr
                            y_rescue_drama.htm>
                          • Jerry
                            I m trying to get that link to work - I turned off Wrap message text this time. Here s an article that adds support for the lifeline idea. Add boarding
                            Message 13 of 14 , Aug 31, 2004
                              I'm trying to get that link to work - I turned off "Wrap message
                              text" this time.

                              Here's an article that adds support for the lifeline idea. Add
                              boarding features to that short list of disaster prevention measures
                              and this man's day would not have turned out quite so bad.

                              -Jerry
                              SF Pelican 12

                              <http://www.baycrossings.com/Archives/2003/10_November/harbor_bay_ferr
                              y_rescue_drama.htm>
                            • Jerry
                              Some pictures of open ocean storm waves at this link: http://tinyurl.com/3qhbb -Jerry
                              Message 14 of 14 , Sep 3, 2004
                                Some pictures of open ocean storm waves at this link:

                                http://tinyurl.com/3qhbb

                                -Jerry
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