djlewis

MHO, FWIW after pondering it all, is that wind effects in normal conditions are about 0.1% as important as body mechanics. And in high winds, it might rise to 1%, at least regarding feather-or-not -- a storm paddle is a different matter. So, once more -- let's hear it for the 99% -- Occupy Rockport! And yes, we are now in technical outer space. But in the past, I've noted that lots of folks enjoy these discussions as spectator sport, much the way I enjoy an NBA game or grandmaster chess match -- fun to watch but I don't know even 5% of what's really going on in the highest reaches of strategy, tactics and execution. And I wanna know the outcome. Navier and Stokes -- sounds like a good outfit to make kayaks or maybe paddles. Different Stokes, eh? Bye. --David

One point I forgot. P only counts when the dry blade is moving forward. And that happens for a very brief time in the stroke. Apart from that, the dry blade just adds to the wind resistance of kayak -- and paddler's body, I should have mentioned. And even that is equivocal, as the dry blade naturally turns quite a bit during a forward stroke. So, that's more evidence that in normal wind conditions, feathering is not much of a factor from an air drag standpoint. And, as I think about it, the problem in high winds is a least as much paddle control as it is wind resistance. A high wind can make the paddle hard to handle, and I'm not sure feathering can help much there, as wind can come from any direction. A storm paddle is a real advantage, however, for just that reason -- much less surface altogether in the air. It's a bit like the common misconception in rolling that lifting your head is bad because of its weight. If you do that math/physics, or just think about it intuitively, you'll see that head weight is also a minuscule factor, in this case not even worth a moment's consideration. The real reason to keep your head down in a roll is -- once again -- body mechanics!

You are correct, Dr.G. You win this round of scientific challenge, so we are now even. However, your reasoning is a bit incorrect, and I think it still leads to some questionable conclusions. I'll model it mathematically for the geeks among us -- glad to explain in more detail if non-geeks would like to get in on it. Let W = wind speed, K = kayak speed over water, P = speed of the dry paddle blade (up in the air) relative to the kayak. You have W = 25 and K = 5. To try this out, set P to something like 12. We are looking for D, average apparent paddle speed against the air -- D for drag, even though it's not really drag in the technical sense. But the higher D is, the higher the actual drag, so it'll do for now. The relevant equations are: Kayaking into the wind: D = - W - K - P. The minus signs are because all the air forces are against the paddler. The wind is negative because it is against you. The K term is negative because your boat speed is "against" you as well -- you feel an apparent wind against your face even when paddling in still air. Likewise, the dry blade of the paddle is against you as well, and P is the additional measure of that beyond kayak speed. Kayaking with the wind: D = W - K - P. This says the wind is now with you so it's positive, but the kayak and air paddle are still against you, as they always are. Now assuming these two cases are equally likely throughout a trip, we simply average them to get the expected (technical term) paddle drag at any moment: Expected (average) D = ((- W - K - P) + (W - K - P)) /2 = - (K + P) Wow, what happened to W -- it's gone, cancelled out! What this says is that, with wind and kayak direction random throughout the day, the effects of wind cancel out on the average. What's left is the fact that the kayak speed (wind in your face in still air) and dry blade (additional wind in its face) both work against you at all times, including in still air and not any more in wind. This makes sense intuitively as well as mathematically. So, what does feathering do? It reduces P and thereby reduces average "drag". So you are correct, but it has nothing to do with wind -- it's only the effect of kayak and blade in still air that count. So it's a good question how big that P factor really is. But now that we know that wind is not an issue on average, the drag we control by feathering is just from the paddle moving through still air. How much can you get a kayak to move by waving it in the air? Now much, if any. Yes, wind against kayak and paddler's body is a significant factor -- but the surface area of a paddle blade is a lot less than those, maybe 15%. So is paddle drag a factor at all? I doubt it -- under normal circumstances. But how about abnormal circumstances, like a high wind? Yes, Dr.G., I have assumed all effects are linear, that is, double the wind and it doubles the drag. And yes, that's not always true even as an approximation. At high wind you get significant turbulence around the dry paddle blade, so at some point doubling the wind more than doubles the air paddle drag. Many of have experienced that and it's not pleasant. But how high does the wind have to get before that's a measurable effect? You're the engineer here, Dr.G., so I'll leave it to you. But my intuition says the wind has to be pretty high before anything significant happens there. How much of a sail can your paddle be with winds under, say 15-20 kts -- not much -- try it. And it the wind's up in the high 20's, 30's or -- heaven forbid -- higher, why are you out on the water? Well, maybe you got caught by unexpected conditions or forgot to check the forecast. Hmmm... that puts you in about the same spot as a traditional Inuit out hunting. -- no electronic forecast and no choice. And guess what -- traditional Inuits carry a storm paddle for the this exact reason! And perhaps we can conclude with the Inuits that only in a storm does air drag on the paddle matter enough to worry about, and only then do we need to switch. Instead, folks seem to recommend feathering at all times for the extremely unusual circumstance of high wind against you (and it might just be with you at that point). ------------------ As for left-coast racers feathering their blades, do we know why they do? Well, you are a racer, and if you feather because of the wind factor, then this analysis shows you are not quite on the mark -- it's typically a minuscule factor among many more important ones. In particular, much more crucial to a racer -- if I may be so bold -- is stroke mechanics, and that, IMHO, is where the feathering matters. And likewise for recreational paddling. So Jason's right -- do what feels good to your body. I think I recall that Ben Lawry recommends feathering at a relatively low angle for just this reason, but he has a very nuanced account of stroke mechanics.

Y'know what they say -- kayaks are just speed bumps. Did that ferry even *know* it hit something? But I think Jason has an ulterior motive for that rule, given that he drives the biggest kayak in the fleet! ;-))) --David.

I never understood the wind resistance thing re feathering. There are 360 degrees and the wind can (and will) come from each of them with probability 1/360 -- what x degrees giveth, 180+x degrees taketh away. Well, I guess you could adjust the feather precisely with every change in heading and shift in wind, but somehow I doubt that's what those fancy adjustable feather gadgets are for. So why feather at all? I've been told that feathering (at some angle or other) optimizes blade and wrist positioning throughout the stroke. I dunno, but I've gone from 60 to 30 degree feather, and to tell the truth, I quickly adjust to any change. Plus, there is a whole coast -- the left one -- full of non-feathering paddlers. But whaddatheyknow? The way I handle wrist and RSI issues is in the gym. Years ago I worked up to high reps with small weights of forward and reverse wrist curls, and my wrists AND elbows have thanked me ever since! Sound forward stroke mechanics also help, and I've worked at that pretty hard, thanks to said Mr. Lawry and others.

Seems like the laws of thermodynamics (one of them -- forget which) would support your observation. Interval (bursty -- up and down) patterns are good for building physiological capacity, but are less efficient. At this time span (a few strokes) the smoothest energy expenditure curve is likely the best. Of course, that's not true for a longer time span, like a whole race, because of physiological and psychological considerations like fatigue, a "kick", or a head-to-head race-within-a-race.

I see harbor water temp of 48F -- that's absolutely drysuit territory. Or, as Scott C once said to leader trainees when temps were similar (in early May) -- you can wear a wet suit if that's what you've got and you'll be uncomfortable, but you won't die. Not a situation to attract L2 paddlers, new or experienced. I agree with Al -- June is going to be glorious -- let's start getting those L2 and L2-to-L3 trips up there now for June or even late May, and by the end of the season, we'll have a super cadre of experienced paddlers.

Hey, Jason -- go ahead and try it. It's not terribly hard to put up MediaWiki. Write an introductory article yourself, a bit of structure (header pages for put-ins, maybe a couple more such as trip levels, for starters) and write a couple of put-in pages yourself to show how it's done. I'll pitch in a couple too, though I can't make any long-term commitments. People might contribute local info on put-ins, like best times, parking gotchas, nearest bathrooms, etc. I love wikis! --David

Typically collaborative wikis do not do well for groups whose members are not technically inclined. One problem is general technical inertia and avoidance. But a big specific issue is the editor that comes with all non-commercial wikis -- including media wiki -- either uses text with cryptic markup or has a very primitive wysiwig interface. If you go with the text, then you pretty much cut out anybody with the even the least tech-resistance, and even many geeks who find editing with such tools to be tedious. Yeah, I know that this message board uses mostly straight text (plus those annoying animated emoticons). But board posts are very short, simple pieces with little need for formatting or fancy layout. The same cannot be generally said for wiki articles. Another impediment to widespread usage is the need for cross-links and organization, at least if you really want to capitalize on the beauty of wikis. Most people do not want to worry about things like that. The most successful wiki projects have a small cadre of editors who are enthusiastic enough to suffer the editing hassles and to put energy into articles, links and structure, not to mention cleaning up after other folks. So your best bet is to get up-front commitments from a core of folks willing to play those roles. My $000.02, from experience.

Yup... I see that. Actually, Brown does not even have a category called "short tow", so I assume that's what he means by the subcategory "clip in" under "contact tow". So he's on the other side from me. Well, my authority was someone of roughly equal "rank" in the coaching community. I guess even experts differ. I just find my definitions more logical and easier to communicate. Then again, I have often been amazed at the lack of consensus among coaches. For example, I have found that the question of whether a "carved turn" or "skidded turn" is on the inside edge or the outside edge to roughly split the coaching community. They can't both be right, of course. In fact simple observation of the wakes of turning boats will tell you which way is correct -- and lots of prominent coaches have it wrong. Of course, they're all good paddlers, much better than I am, so maybe who cares. But it can be confusing.

Wellll... that would violate one of the primary distinguishing features (and advantages) of a contact tow as I defined it, namely the ability to release very easily, simply by letting go. It's also easy to engage a contact tow . Those two are probably the major factors in favor of a contact tow as you decide what technique to use in a given situation. Perhaps yours should be called a _very_ short tow. You can call it what you want, but it ain't a contact tow in my book, fwiw. Maybe we should call it a banana. Or let's call it a day. --David

I highly recommend this course and the instructor! Todd is the best at this that I have seen.

I know this may be futile, but the terminology has gotten a bit crossed up in the past few years. Here's how I learned it, and have fairly recently verified with a couple of top coaches... contact tow -- n. a tow executed without any line, simply by the towee holding onto the tower's boat (or person) with a hand. short tow -- (1) n. a short tow line intended to hold the towee's boat alongside the tower's boat rather than trailing behind; (2) n. a tow executed with a short tow line. If you want to continue using "contact tow" for "short tow" as defined above, fine. But then please propose another term for the above definition of "contact tow", as you've stolen its proper name. The contact tow (as defined here) is a very important technique -- it definitely needs a unique name.

Very cute! But... Did anyone else wonder how (at 2:00-2:09) how picks up a 60+ lb plastic boat effortlessly with one hand, then hoists it over his head with ease and balances it perfectly on the first first try. And the boat is stable front/back all the while, even as he changes the grip/balance point at least twice. Boy, I wish my boats did that! Even if I were strong enough, getting it to balance perfectly like that would be quite a challenge. I suspect the explanation is related to the fact that the extreme bow and stern of the boat are not visible in the frame while he is picking it up and hoisting the boat. Whatcha think?!

I just posted an L2 paddle in the Great Marsh for Sunday, June 17, B-in-B at 9:30 (to catch the high tide). This is a lovely trip that we've offered quite a few times in past years. http://www.nspn.org/forum/index.php?app=calendar&module=calendar&cal_id=1&do=showevent&event_id=814 No rush right now (in March) obviously, but please post here or e-mail me (djlewis at triadic dottie commie) if interested, so we can plan the launch site -- for easy or harder L2 -- and, if well-subscribed, maybe both. All levels from beginning L2 up are welcome. A few more experienced folks along will make splitting possible.

I am signed up for the Haverhill pool this afternoon (2:30) but can't make it. So if anyone wants my slot, just reply here -- first one takes it for free. --David

If it matters to you, the Surge is quite hard to roll. Of course, the Quest isn't an easy roller either. --David

Yup, same for me -- rinse it in fresh water (from the tap) -- drain it quickly and work the knob a bit -- repeat a couple of times -- stiff knob all fixed.

I second these two sources for waterproof charts -- I use them a lot, especially the Waterproof ones. I have a bunch of laminated charts that I used to piece together from printouts from Maptech software (a bit tedious at first, but I got really good and quick at it). These are great -- when they fit the trip. But often as not a trip requires two or three of them, since I could not anticipate all possible routes (without making a huge inventory of overlapping laminates). Sometimes, however, when neither of these quite does the trick, I do use a chart case with a paper chart. I also second Suz's choice of the Ortlieb case -- the only one I have found that really seals well, stays dry inside, and does not break down in one way or another after a season or two. And like Suz, I sometimes put a waterproof chart inside a case, redundant as that seems. But sometimes I carefully pre-fold it for the trip and tape the folds in place, and skip the case. But one thing I would never do is depend on a mapping GPS and not carry a chart. GPS's break down, batteries die, etc. Plus, that teensy screen just cannot convey as much useful information at a glance. I do admit to sometimes using a GPS for nav, but there's always a chart on the foredeck as well.

Don't *know* but it sure looks plausibly real -- the gulls are a great touch.

The narrated version says "connects up to a surface parking lot". The text also says there is parking.

They call it a success... but he got a collapsed lung and a shoulder socket fracture out of it. But the guy before him blew out his knees and the one after him broke his back. Guess that makes it a success. He says he has something new up his sleeve. Couple more like this and he'll have great memories as he lies in bed at age 34, unable to feed himself, much less kayak. Darwin award to him!

Yes, it is cheap. Maybe I'll try it. But I just looked at my collection of old, non-functional cases and see why I am gun-shy. Not a question of wanting. I want. Letcha know when I *can*.

Hi, Kate: Love to come see -- and paddle -- with you. But why'd you move so far away I miss my informal Greenland rolling lessons on Walden! (Loved your Nova Scotia report and pictures!) I don't quite understand why items that NRS contracts out can't be sold in REI or other places. My guess is that the majority of NRS branded items are manufactured by someone else. It seems unlikely that they have their own factories for everything from wet suits to paddle boards to water shoes. Maybe the chart case is too recent to have made it into other catalogs yet. In any case, it's useful to know the NRS chart case has a zip-lock type closure. But that raises an issue of durability in my mind -- how many open-close cycles will it endure before deteriorating? I think one of the many chart cases I have tried and discarded over the years had a similar closure. Glad to hear that NRS's is easy-close, however, as I seem to recall that with the other zip-lock I tried was hard to be sure it was completely sealed -- maybe that was the same as yours (ah here it is -- Seal Line). --David