I was struck by the number of times tidal currents played a role in the accidents in the book Deep Trouble. The term 'swept out to sea' stirs up some pretty scary images but how bad can it really be? Given that a person can stay in the boat, how far out can they be swept? A mile, two miles? Even at full ebb, the tidal (not ocean) current has to dissipate somewhere. Granted one might well spend some uncomfortable hours and then have to paddle back, but still...... *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
One of my friends, Duncan Taylor, while in view of his wife on shore, was swept out to sea while kayaking at a beach in Maurtius. Despite an intensive air-sea search, no trace of him was ever found. Richard Culpeper www.geocities.com/~culpeper ---------- > From: Sisler, Clyde <Clyde.Sisler_at_wang.com> > To: 'Paddlewise' <paddlewise_at_lists.intelenet.net> > Subject: [Paddlewise] Tides & Currents > Date: Tuesday, January 26, 1999 8:20 AM > > I was struck by the number of times tidal currents played a role in the > accidents in the book Deep Trouble. The term 'swept out to sea' stirs up > some pretty scary images but how bad can it really be? Given that a person > can stay in the boat, how far out can they be swept? A mile, two miles? > Even at full ebb, the tidal (not ocean) current has to dissipate somewhere. > > Granted one might well spend some uncomfortable hours and then have to > paddle back, but still...... > *************************************************************************** > PaddleWise Paddling Mailing List > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.gasp-seakayak.net/paddlewise/ > *************************************************************************** *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
> One of my friends, Duncan Taylor, while in view of his wife on shore, was > swept out to sea while kayaking at a beach in Maurtius. Despite an > intensive air-sea search, no trace of him was ever found. I could not find this placename. I did find a place "Mauritius", an island off the East coast of Madagascar. I guess the question there becomes, did he have a GPS and compass? I think most of us ocean paddlers always have the fallback position of being able to select the general direction of the coast line, paddling perpendicular to the current for some distance, and then heading for shore. A person swept out to sea off an isolated island has a much more difficult problem, in that their default safe return course can't be assumed like "if I head west or north, I can't help but hit land." A lesson here I suppose is that if you aren't surrounded by land like on a lake, be sure to have an adequate water supply and navigational gear that will allow a return from 20 miles out in any random direction. Even if you are just surfing, how hard can it be to slip a pre-packed drybox and a couple 2 liter bottles of water in your rear hold. Richard Walker Houston, TX http://www.neosoft.com/~rww/kayak_log.html *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
One of my friends, Duncan Taylor, while in view of his wife on shore, was swept out to sea while kayaking at a beach in Maurtius. Despite an intensive air-sea search, no trace of him was ever found. -------------- That must have freaked his wife out. What kind of skills and wind & wave conditions? *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Here in Florida, if you're swept into the Gulf Stream, about 3 miles off shore, you can end up in Ireland.... Far enough?! *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
My brother lives on Mauritius. When was this and where? Gran Bay? > -----Original Message----- > From: owner-paddlewise_at_lists.intelenet.net > [mailto:owner-paddlewise_at_lists.intelenet.net]On Behalf Of Richard > Culpeper > Sent: Tuesday, January 26, 1999 8:47 AM > To: Sisler, Clyde; 'Paddlewise' > Subject: Re: [Paddlewise] Tides & Currents > > > One of my friends, Duncan Taylor, while in view of his wife > on shore, was > swept out to sea while kayaking at a beach in Maurtius. Despite an > intensive air-sea search, no trace of him was ever found. > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Yes, it did. It hurt many people, for Duncan was a very special person who had touched many lives. He was an experienced inland wilderness canoeist (and for many years was president of the Wilderness Canoe Association), but was inexperienced at kayaking and ocean paddling. He was at a resort on the south side of the island, where he came upon a kayak rental on the beach. He rented one and went for a spin, so he had no understanding of the local conditions, and no proper equipment, water, etc. The conditions were pleasant, with some waves out from shore. His wife described him bobbing along and, as he got further out, disappearing from sight between the waves. There is a possibility that he was dumped in these waves, but this does not explain his disappearance. The consensus is that he ended up in the ocean current (either in or out of his boat), heading for Africa, and air-sea serches were mounted to that effect. It looks like he had enough technique to paddle into trouble, but not enough experience with salt water ocean sea kayaking to have avoided troube in the first place. Richard Culpeper www.geocities.com/~culpeper ---------- > From: Sisler, Clyde <Clyde.Sisler_at_wang.com> > To: 'Paddlewise' <paddlewise_at_lists.intelenet.net> > Subject: RE: [Paddlewise] Tides & Currents > Date: Tuesday, January 26, 1999 9:33 AM > > One of my friends, Duncan Taylor, while in view of his wife on shore, was > swept out to sea while kayaking at a beach in Maurtius. Despite an > intensive air-sea search, no trace of him was ever found. > > -------------- > > That must have freaked his wife out. What kind of skills and wind & wave > conditions? > *************************************************************************** > PaddleWise Paddling Mailing List > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.gasp-seakayak.net/paddlewise/ > *************************************************************************** *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Mauritius is similar to many of the Caribbean or Hawaiian islands. It's a pleasant, non threatening tourist environment and one really wouldn't be too concerned about currents, etc. I have seen the kayaks, and they are for rent at most of the typical tourist hotels. They are actually fg SOTs and well made. Of course most tourists paddle around the lagoon, but if he paddled through the reef, then he may have been swept away or dumped on the reef and eaten. There was a case of a guy who rented a jet ski in Cancun a few years ago and was never seen alive (or dead) again. His wife paid thousands for an air search and had her credit card debited for the cost of the ski. Just because the water is blue, flat and warm, doesn't mean it's a walk in the park! cya *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Hi Clyde, If I recall correctly, most of the accidents involving currents in Deep Trouble were problems specificly associated with crossing eddylines. The eddyline caused a flip, thus leaving the paddler at the mercy of the currents. In the two stories I am thinking of, the paddlers were unable to self-rescue the boats because of swamping and lack of adequate flotation, but if those paddlers could have self-rescued, it would have been possible for them paddle back to shore fairly easily. In the San Juans at least, the currents usually are not faster than fast paddling speed except for localized areas near shore where the current speeds up (e.g. eddylines and tide rips). These local areas are fairly easy to paddle around, given a rudimentary knowledge of currents and eddylines. Sometimes though, it is impossible to avoid being swept into an eddyline, which is why I evangelize a little bit of whitewater experience even for those who never plan to take up whitewater as a sport. It doesn't take much practice on the river to be able to handle eddylines with ease. Cheers, Kevin Kayak Academy Whitewater Instructor http://www.halcyon.com/kayak On Tue, 26 Jan 1999, Sisler, Clyde wrote: > I was struck by the number of times tidal currents played a role in the > accidents in the book Deep Trouble. The term 'swept out to sea' stirs up > some pretty scary images but how bad can it really be? Given that a person > can stay in the boat, how far out can they be swept? A mile, two miles? > Even at full ebb, the tidal (not ocean) current has to dissipate somewhere. > > Granted one might well spend some uncomfortable hours and then have to > paddle back, but still...... > *************************************************************************** > PaddleWise Paddling Mailing List > Submissions: paddlewise_at_lists.intelenet.net > Subscriptions: paddlewise-request_at_lists.intelenet.net > Website: http://www.gasp-seakayak.net/paddlewise/ > *************************************************************************** > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
As a local oceanographer and kayaker with some experience in and knowledge of the San Juans and similar regional waters (although not as much as K. Whilden's fabled employer at Kayak Academy), I would like to make several points of fact and/or opinion: 1) The other answers to Clyde's question, regarding Mauritius, did not seem to address his point about "tidal" as opposed to "ocean" currents. Tidal currents are inherently oscillatory with about a 6.25- or 12.5-hour average period, depending on location. Hence Clyde's suggestion that if one could stay with (preferably IN) the boat long enough, one should return to one's approximate starting point in half a day at most. Large-scale wind-driven ocean ocean currents (such as those around Mauritius), in contrast, are generally unidirectional for long periods of time. Any prevaling local wind and wave transport would add to the latter hazard. 2) In a statistical sense, Kevin may be correct that "currents usually are not faster than fast paddling speed," i.e., over a majority of the area for a majority of hours on an annual basis. However, there are several channels in the San Juans where currents exceed 2-3 knots over most of their width and length for several hours a day and for several successive days during spring tidal periods (around new/full moon), especially during May-July and November-January. That's fast for me to paddle for a period of hours (shorter burst are OK). Maximum currents exceed 4 knots in many areas during these times. Thus I would argue that strong currents are common enough to get the uneducated paddler into conditions where he/she could not control his/her position for several hours at a time. P.S. This happened to me in my greener years. 3) Many experienced paddlers I've met also seem to assume that slack currents are synchronous with high and low water. In the San Juans, as in many other narrow channels, however, currents and water levels are commonly (not always) out of phase, often by as much as 1-2 hours or more. Failure to read tidal current tables instead of tidal height tables is particularly dangerous where high/low water occurs AFTER slack, such as occurs in Deception Pass (8 knot maximum currents), so that the unwary paddler would potentially launch into an accelerating current. 4) There are large open-water areas in the San Juan vicinity, as well as long channels, both of which may have strong currents over broad areas (tens of miles). It is not hard for a paddler to piggyback tidal currents intentionally for 10-12 miles on a single tidal cycle in some places, so the displacements in an accidental scenario can be greater than what Clyde is visualizing. Furthermore, distance from shore would logically seem to diminish the odds of rescue. 5) The complex current patterns in the San Juan area, including large scale eddies and significant differences in the timing of current stages over short distances, could easily result in a paddler not being able to retrace his/her path when the current reversed, but rather being entrained into another channel altogether. 6) The bottom line, to amplify Kevin's point, is that being "swept out to sea" is not so much the issue (in the San Juans, anyway), so much as being swept uncontrollably into areas with hazardous conditions such as eddylines, tide rips, high seas, or oil tankers :-(. Thank you for listening to my sermon. Richard Strickland Seattle ---"K. Whilden" <kwhilden_at_u.washington.edu> wrote: > If I recall correctly, most of the accidents involving currents in Deep > Trouble were problems specificly associated with crossing eddylines. The > eddyline caused a flip, thus leaving the paddler at the mercy of the > currents. [SNIP] > In the San Juans at least, > the currents usually are not faster than fast paddling speed except for > localized areas near shore where the current speeds up (e.g. eddylines and > tide rips). These local areas are fairly easy to paddle around, given a > rudimentary knowledge of currents and eddylines. Sometimes though, it is > impossible to avoid being swept into an eddyline... > On Tue, 26 Jan 1999, Sisler, Clyde wrote: > > > I was struck by the number of times tidal currents played a role in the > > accidents in the book Deep Trouble. The term 'swept out to sea' stirs up > > some pretty scary images but how bad can it really be? Given that a person > > can stay in the boat, how far out can they be swept? A mile, two miles? > > Even at full ebb, the tidal (not ocean) current has to dissipate somewhere. > > > > Granted one might well spend some uncomfortable hours and then have to > > paddle back, but still...... _________________________________________________________ DO YOU YAHOO!? Get your free _at_yahoo.com address at http://mail.yahoo.com *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
On Tue, 26 Jan 1999, Richard Strickland wrote: <snip> > 2) In a statistical sense, Kevin may be correct that "currents usually > are not faster than fast paddling speed," i.e., over a majority of the > area for a majority of hours on an annual basis. However, there are > several channels in the San Juans where currents exceed 2-3 knots over > most of their width and length for several hours a day and for several > successive days during spring tidal periods (around new/full moon), > especially during May-July and November-January. That's fast for me to > paddle for a period of hours (shorter burst are OK). Maximum currents > exceed 4 knots in many areas during these times. Thus I would argue > that strong currents are common enough to get the uneducated paddler > into conditions where he/she could not control his/her position for > several hours at a time. P.S. This happened to me in my greener years. Hi Richard, Thanks for your very informative post! I intentionaly left out of my post any reference to large spring currents and some of the constricted channels such as Obstruction Pass where currents can get faster than maximum paddling speed. I wanted to see if anyone was paying attention. You passed my informal and probably unnecessary test with flying colors. In fact, considering how much I learned from your post, maybe I should do this kind of thing more often. Nah... Now one more comment about paddling against currents. Don't do so unless absolutely necessary! It is far too much work and effort, and very difficult if the current is above three knots. It is very difficult to paddle against even a one knot current, and three knot current is almost impossible except for short distances. It is much better to plan to paddle with the current. One of my favorite trips in the San Juans is to paddle from Washington Park on Fidalgo Island to Doe Bay on Orcas Island, leaving just as the current turns to a spring flood. First there is the challenging ferry glide across a current that goes 90 degrees to the direction of travel. This is great practice for using ranging navigational techniques. Then there is a fabulous tide rip on strawberry island to play and surf. And then for the finale, there is a ride on the Rosario Strait Express current with a stop at Doe Bay for a hot tub soak. A lot of fun indeed. Last time I did this trip, we made the 8 nmi one-way distance in 2:04 hours, including a 30 minute stop to play at the rip. So the moral of the story, if there is one, is to let the currents do the work for you, but also learn about eddylines, because they are inseperable. Lot's o' speedy paddling, Kevin *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Here abouts in the San Francisco Bay Area there are a number of paddles easily done "against" the current. We use the reversal currents behind the points to push us along. Then scoot around the points and into the opposing currents, and pop back into the reversals. The key is knowing local conditions. Barbara At 11:07 PM 1/26/99 -0800, K. Whilden wrote: > >On Tue, 26 Jan 1999, Richard Strickland wrote: ><snip> >> 2) In a statistical sense, Kevin may be correct that "currents usually >> are not faster than fast paddling speed," i.e., over a majority of the >> area for a majority of hours on an annual basis. However, there are >> several channels in the San Juans where currents exceed 2-3 knots over >> most of their width and length for several hours a day and for several >> successive days during spring tidal periods (around new/full moon), >> especially during May-July and November-January. That's fast for me to >> paddle for a period of hours (shorter burst are OK). Maximum currents >> exceed 4 knots in many areas during these times. Thus I would argue >> that strong currents are common enough to get the uneducated paddler >> into conditions where he/she could not control his/her position for >> several hours at a time. P.S. This happened to me in my greener years. > >Hi Richard, > >Thanks for your very informative post! I intentionaly left out of my post >any reference to large spring currents and some of the constricted >channels such as Obstruction Pass where currents can get faster than >maximum paddling speed. I wanted to see if anyone was paying attention. >You passed my informal and probably unnecessary test with flying colors. >In fact, considering how much I learned from your post, maybe I should do >this kind of thing more often. Nah... > >Now one more comment about paddling against currents. Don't do so unless >absolutely necessary! It is far too much work and effort, and very >difficult if the current is above three knots. It is very difficult to >paddle against even a one knot current, and three knot current is almost >impossible except for short distances. It is much better to plan to >paddle with the current. One of my favorite trips in the San Juans is to >paddle from Washington Park on Fidalgo Island to Doe Bay on Orcas Island, >leaving just as the current turns to a spring flood. First there is the >challenging ferry glide across a current that goes 90 degrees to the >direction of travel. This is great practice for using ranging navigational >techniques. Then there is a fabulous tide rip on strawberry island to play >and surf. And then for the finale, there is a ride on the Rosario Strait >Express current with a stop at Doe Bay for a hot tub soak. A lot of fun >indeed. Last time I did this trip, we made the 8 nmi one-way distance in >2:04 hours, including a 30 minute stop to play at the rip. > >So the moral of the story, if there is one, is to let the currents do the >work for you, but also learn about eddylines, because they are >inseperable. > >Lot's o' speedy paddling, >Kevin > >*************************************************************************** >PaddleWise Paddling Mailing List >Submissions: paddlewise_at_lists.intelenet.net >Subscriptions: paddlewise-request_at_lists.intelenet.net >Website: http://www.gasp-seakayak.net/paddlewise/ >*************************************************************************** > > *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Thanks for your very informative post! I intentionaly left out of my post ------------ I add my thanks also, Richard, that was a great post although I personally wouldn't have thought of oscillatory as an adverb. Cyclical, maybe. Oscillatory, I don't think so! :-). ------------ Now one more comment about paddling against currents. Don't do so unless absolutely necessary! It is far too much work and effort, and very ------------ The image I have now of the Deep Trouble reports is of people paddling madly, more from reaction, adrenilin and fear than with any plan or objective in mind. This eventually would lead to fatigue and even less control of the boat and the situation. The thought behind my post was simply being caught in a current I couldn't overcome or evade and being swept past the last point of land. Rather than paddling wildy to obtain an unreachable objective I thought it might make more sense, under the right circumstances, to conserve energy, stay upright and (wishfully) trying to ferry out of the current if/when conditions permitted. Granted wind, waves, skill, fatigue, etc. all come into play along with the current but I didn't/don't think being swept past that last point of land is neccessarily a death sentence, at least not most of the time. I agree with another post that some whitewater experience would be invaluable. Being able to punch in and out of an eddyline without leaning the wrong (natural) way is important (and fun) as is ferrying or setting (isn't that what they call ferrying while heading with the current?). How else are ya gonna get out to those standing waves for a little surfing? :-) My whitewater canoeing is 20+ year old but little bits and pieces seem to surface when needed. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
Aside from the issue of being swept by the tide out into something such as an ocean current, there is also the problem of what might happen out in the briny even if the tide will pretty much bring you back. Sometimes walking back is not feasible (due to deep water channels and mud flats), leaving you unprotected for extended periods where a shift in the wind could build some nasty breakers in the shallows (e.g. Hannah Bay at the southern edge of Hudson's Bay). (BTW, when I was a youngster I bunged up an empty oil barrel, lashed some driftwood to it, and happily floated out with the tide from our cottage on Oak Bay on the Bay of Fundy. I bobbed about until the tide brought me back in again. I did not realize that I would be out for so long, so I was expecting my folks to be angry with me. As it was, they were not, for as I later learned from my mother, she had spent a fair number of years as a child bobbing in and out with the tide, and thought nothing of swimming for extended periods. Sometimes I wonder how she and her siblings ever survived to adulthood.) Cheers, Richard Culpeper *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
> Here abouts in the San Francisco Bay Area there are a number of paddles > easily done "against" the current. We use the reversal currents behind the > points to push us along. Then scoot around the points and into the opposing > currents, and pop back into the reversals. > The key is knowing local conditions. True fact, Barbara, in the San Juans as well as that other San. Using hte back eddies was how I saved my tush when I misread the currents in the "greener" days I referred to. Richard in Seattle _________________________________________________________ DO YOU YAHOO!? Get your free _at_yahoo.com address at http://mail.yahoo.com *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
> I personally > wouldn't have thought of oscillatory as an adverb. Cyclical, maybe. > Oscillatory, I don't think so! :-). > ------------ To quote: "Tidal currents are inherently oscillatory.." In this usage, "inherently" is an adverb and "oscillatory" is an adjective.The adverb (if one accepted its existence) would be "oscillatorily," meaning "in an oscillatory fashion." Didn't know I was an editor, too, did you? > ------------ > The image I have now of the Deep Trouble reports is of people paddling > madly, more from reaction, adrenilin and fear than with any plan or > objective in mind. This eventually would lead to fatigue and even less > control of the boat and the situation. Agreed. > The thought behind my post was simply being caught in a current I couldn't > overcome or evade and being swept past the last point of land. Rather than > paddling wildy to obtain an unreachable objective I thought it might make > more sense, under the right circumstances, to conserve energy, stay upright > and (wishfully) trying to ferry out of the current if/when conditions > permitted. Certainly wasting energy to reach an unreachable objective is not intelligent paddling, and conserving energy when possible is. > Granted wind, waves, skill, fatigue, etc. all come into play along with the > current but I didn't/don't think being swept past that last point of land is > neccessarily a death sentence, at least not most of the time. That may be generally so. I don't know where you paddle, but anyone who has been to the San Juans should appreciate the other generalization I was trying to make about them--that difficult sea conditions are common enough that current/wind/wave conditions do more than "come into play." I would argue that they are often the dominant factors one must deal with. I do not generally advocate exhaustion, and I do unequivocally favor paddling/bracing/rescue skills. However, I have been in situations in the San Juans where some strong, sustained effort exerted at the right time in the right direction kept me in moderate sea conditions when currents that I had not anticipated were trying to take me someplace really ugly. An ability to read the water and anticipate and avert impending danger (if possible) is as much of a paddling skill as bracing, etc. Richard in Seattle _________________________________________________________ DO YOU YAHOO!? Get your free _at_yahoo.com address at http://mail.yahoo.com *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
On Wed, 27 Jan 1999, Richard Strickland wrote: > > That may be generally so. I don't know where you paddle, but anyone > who has been to the San Juans should appreciate the other > generalization I was trying to make about them--that difficult sea > conditions are common enough that current/wind/wave conditions do more > than "come into play." I would argue that they are often the dominant > factors one must deal with. Agreed! Although there are areas in the San Juans where currents are small, and also times of the month away from full or new moons can be fairly benign current wise. Still, there are always local areas of strong currents (i.e. rips) that are easy for the unwitting paddler to be swept into and encounter trouble. I do not generally advocate exhaustion, > and I do unequivocally favor paddling/bracing/rescue skills. However, > I have been in situations in the San Juans where some strong, > sustained effort exerted at the right time in the right direction kept > me in moderate sea conditions when currents that I had not anticipated > were trying to take me someplace really ugly. An ability to read the > water and anticipate and avert impending danger (if possible) is as > much of a paddling skill as bracing, etc. > Here here! This is something I have been saying for quite a while. The abilty to read the water, which means to be able to pick up the subtle clues from waves and currents, is every bit as important as knowing how to brace or roll, or even paddle in a straight line. Unless you paddle exclusively on glassy lakes, there will be sometime when you will encounter locally rougher conditions due to a current/wind/wave interaction. being able to spot this in time to avoid it, or to know even in which direction the current is flowing requires practice. And where does one get the most effective and safest practice at reading rough water and wind/wave/current interactions? (Note: at the risk of sounding like a broken record....) The river!! When I first started teaching the whitewater course for George Gronseth, I had not clued into the importance of reading water. Now I know it is crucial to developing basic paddling skills. Most beginning river paddlers neglect this skill on a conscious level, but if they keep paddling, it eventually becomes instinctual. The challenge for me was learning how to teach instincts in only two days, because half of my students have no intention of taking up river kayaking, but are taking the class one to improve their sea kayaking skills. More than any other thing, I have to remind my students to think about reading the river. All of the other skills become much easier to use once the students know exactly where and when to apply them. An analogy that I like is the equate reading the water with knowing the rhythm when partner-dancing. In salsa or swing for instance, knowing all of the steps, spins, and moves is one thing, but without rhythm this is pretty much useless. With rhythm, all of those steps, spins and twirls are effortless and look and feel great! Cheers, Kevin Whilden The Kayak Academy (http:www.kalcyon.com/kayak) *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
---Dave Kruger <dkruger_at_pacifier.com> wrote: > > ... That is, maximum forward speed (maximum flood) > > would coincide with high water (as the wave crest passes), max ebb > > would occur at low water (wave trough), and slacks would occur halfway > > between. This model conforms to the two observations you made (below): > > slacks are (ideally) 3 hours out of phase with high/low water, and > > currents are the derivative of the heights (since sine and cosine are > > derivatives of each other and 90 degrees out of phase). > > Richard, there is an inconsistency in the above. I > think if "currents are the derivative of the heights" then max current > should occur mid-tide, not at max-tide (and min-tide), which is what > "maximum forward speed (maximum flood) would coincide with high water" > suggests. I believe you meant to say both tides and currents were > *in-phase* for this model. Correct? I stand corrected before God and Paddlewise. Forgive the hurried-over math. Max speed at max elevation would indeed be in-phase. (Corrected by a chemist--oh, the shame of it!) > What we have here corresponds more closely to the "standing wave" model > because in model 2), max-tide (and min-tide) > both correspond roughly to *slack* (attributing the hour or so offset to > the effects of superimposed downriver current). This is the model which > has tide height and current velocity 90 degrees out of phase, I believe. Right again. I would have to analyze the "offset" to confirm whether it results from river current. At the risk of getting this mixed up again in translating my island mentality to a river mentality, the bias toward ebb generated by the river flow should, over the long term, make the flood phase of the cycle shorter than the average 6 hrs 25 minutes and the ebb phase longer than that. As I visualize it, analyzing the relationship of currents to height would be affected by your position along the river, since there would be a salt water "front" that would propagate upstream during the flood and downstream during the ebb. (The leading edge of the front would be along the bottom and the surface would lag, but it is the surface we are interested in as paddlers, yes?) Upstream of the front, the current should always be ebbing even as the water level is rising (at decreasing speed closer to the front as the front forges upstream during flood). Downstream of the front, the current & height should be correlated more as we have discussed. Thus the tidal pattern at a given site would change as the front swept back and forth past it. So it would seem to be a fairly complex situation. Perhaps the situation is simplest in Astoria, close to the mouth. Maybe some more insights will come to me in the hot tub tonight ;-). And maybe you have some ground-truth observations to share. I don't know offhand the river distances over which the tidal front ranges in the Columbia, but if I recall correctly, tidal effects are felt as far upstream as Portland. > The piece of the dialog which really illuminated the difference between > what we have here and what happens in the San Juans was this: > > > Currents in that area are considered to be partly hydraulic, that is, > > driven by differences in sea level from one side of the channel to the > > other. These differences result, for example, when incoming tides > > "pile up" water on the upstream sides of the islands faster than the > > water can drain downstream through the channel. Then, when the water > > level starts falling after high tide, water level is still higher on > > the upstream side than on the downstream side. Thus the flood > > continues (even after high water has passed) until the level is equal > > at the two ends of the channel, resulting in a slack. Then the situation > > [reverses]. > > I only see this in minor side-channels of the Columbia which are separated > from the main River by a very narrow opening. The main stem Columbia down > here never functions like this -- and now (thanks to you) I understand > why: the mouth of the River is too large relative to the vertical > excursion in tide (and consequent horizontal exchanges of water mass). Excuse me, I need to get back to work. Isn't this more fun than metallurgy? Richard in Seattle _________________________________________________________ DO YOU YAHOO!? Get your free _at_yahoo.com address at http://mail.yahoo.com *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************
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