Meta tags:
Headings (most frequently used words):
april, 2015, persistent, wednesday, shifts, part, laser, salience, 22, monday, blog, archive, about, me, shift,
Text of the page (most frequently used words):
the (502), you (148), that (131), and (102), wind (89), shift (67), for (60), this (54), are (54), tack (53), your (51), have (48), #persistent (42), shifts (40), back (38), median (38), more (32), phase (32), with (32), strategy (30), get (29), time (29), but (27), direction (26), mark (25), there (25), from (25), then (24), sailing (24), not (23), will (22), boat (22), leg (22), out (22), oscillating (22), course (22), would (21), line (21), side (21), tacking (20), left (20), when (20), one (20), can (19), right (19), just (18), was (18), come (18), some (18), first (17), make (17), middle (17), leverage (16), because (16), game (16), big (16), lifted (15), which (15), sail (15), oscillations (15), she (15), about (14), scenario (14), what (14), upwind (14), before (14), could (14), long (13), they (13), diagram (13), boats (13), going (12), windward (12), rhumb (12), gains (12), say (11), even (11), should (11), way (11), next (11), how (11), algorithm (11), current (11), tacks (11), last (10), where (10), case (10), small (10), closer (10), been (10), share (9), beat (9), think (9), other (9), inside (9), only (9), towards (9), layline (9), advice (9), heading (9), extreme (9), race (9), second (8), fleet (8), above (8), into (8), has (8), another (8), often (8), takes (8), below (8), like (8), tacked (8), north (8), april (7), were (7), well (7), call (7), tactics (7), play (7), competition (7), stay (7), use (7), being (7), here (7), down (7), than (7), port (7), example (7), part (6), posts (6), place (6), third (6), them (6), might (6), maybe (6), two (6), continue (6), came (6), find (6), put (6), start (6), knocked (6), don (6), degrees (6), these (6), directions (6), getting (6), through (6), playing (6), black (6), ladder (6), red (6), had (6), trace (6), neutral (6), may (5), 2015 (5), blog (5), ahead (5), between (5), however (5), less (5), all (5), usually (5), bit (5), though (5), different (5), after (5), oscillation (5), take (5), good (5), courses (5), away (5), spend (5), same (5), want (5), while (5), strategies (5), very (5), try (5), throw (5), computer (5), need (5), starboard (5), made (5), cashing (5), beginning (5), speed (5), during (5), able (5), short (5), cost (5), real (5), degree (5), her (5), drawn (5), means (5), know (5), ian (4), posted (4), based (4), especially (4), skewed (4), yourself (4), position (4), tactical (4), actually (4), decide (4), headed (4), who (4), until (4), once (4), knocks (4), realize (4), shows (4), close (4), many (4), blogs (4), post (4), pointing (4), far (4), compass (4), any (4), longer (4), over (4), plan (4), overall (4), losses (4), see (4), almost (4), racer (4), major (4), bigger (4), hitch (4), didn (4), thought (4), onto (4), phases (4), following (4), enough (4), still (4), picture (3), january (3), pinterest (3), facebook (3), blogthis (3), email (3), comments (3), reducing (3), larger (3), front (3), hand (3), already (3), shifted (3), confident (3), rest (3), upcoming (3), changes (3), win (3), becomes (3), answers (3), prediction (3), happen (3), now (3), safe (3), wait (3), since (3), without (3), worst (3), happens (3), sailor (3), knock (3), someone (3), using (3), past (3), soon (3), round (3), easy (3), emphasize (3), does (3), always (3), starts (3), goes (3), eventually (3), whatever (3), calling (3), reason (3), move (3), trying (3), better (3), judgement (3), doing (3), top (3), executing (3), difference (3), scale (3), event (3), generally (3), further (3), gain (3), weather (3), around (3), illustrate (3), scenarios (3), www (3), much (3), rungs (3), rung (3), corresponding (3), puff (3), pay (3), four (3), perfect (3), happy (3), little (3), minutes (3), let (3), orange (3), started (3), lake (3), link (3), smooth (3), waiting (3), paper (3), true (3), did (3), screen (3), damped (3), june (2), september (2), march (2), subscribe (2), home (2), catch (2), negligible (2), breeze (2), depending (2), firstly (2), couple (2), again (2), costly (2), angle (2), legs (2), hard (2), end (2), perpendicular (2), best (2), opposite (2), notice (2), overshooting (2), really (2), oscillate (2), keep (2), lot (2), crosses (2), credible (2), coming (2), makes (2), key (2), why (2), act (2), information (2), also (2), possible (2), slightly (2), previous (2), clear (2), simple (2), remember (2), bring (2), forth (2), fairly (2), unless (2), ideas (2), heads (2), necessarily (2), pretty (2), online (2), pick (2), feels (2), yes (2), normal (2), most (2), whenever (2), number (2), numbers (2), people (2), across (2), consolidating (2), probably (2), cross (2), sailed (2), oscillates (2), every (2), basic (2), thing (2), driven (2), effectively (2), slow (2), works (2), mean (2), gradual (2), mistake (2), treating (2), dig (2), definition (2), include (2), similar (2), minor (2), questions (2), please (2), feel (2), wednesday (2), nothing (2), done (2), behind (2), slower (2), straight (2), pays (2), taking (2), account (2), station (2), dirty (2), air (2), racing (2), check (2), defensive (2), input (2), http (2), sailracer (2), net (2), fourth (2), instead (2), must (2), slight (2), according (2), committee (2), perfectly (2), thinking (2), three (2), instantaneous (2), brown (2), average (2), maroon (2), smaller (2), directly (2), angles (2), essentially (2), effect (2), separation (2), against (2), adverse (2), bunch (2), those (2), nice (2), double (2), purposefully (2), lose (2), used (2), combined (2), reasons (2), having (2), continues (2), markset (2), rarely (2), sense (2), ones (2), high (2), immediately (2), yellow (2), bay (2), lift (2), gets (2), stories (2), bottom (2), whether (2), sailors (2), either (2), themselves (2), competing (2), messy (2), world (2), smarts (2), mind (2), laylines (2), bad (2), advantage (2), cashed (2), exactly (2), crossed (2), shadow (2), order (2), looking (2), capture (2), east (2), grey (2), theory (2), took (2), off (2), blindly (2), follow (2), memory (2), practice (2), com (2), laser (2), salience (2), window, theme, powered, blogger, view, complete, profile, july, august, 2012, november, 2013, october, 2014, 2017, december, 2018, 2019, 2026, archive, atom, older, newer, day, regatta, nobody, scoreboard, points, wise, staying, job, caught, standings, covering, ignoring, talk, invalid, assumption, overrule, everything, else, fleets, alone, deny, answer, expecting, considering, stable, advantages, gained, putting, battles, factor, shifting, rounded, speaking, ignore, assume, times, treat, favourable, risk, meantime, along, header, tempting, whose, lined, dealing, set, situation, options, discernible, brings, define, glossary, brevity, forgotten, add, unfortunately, involves, understanding, jargon, saying, winded, snappy, realizes, safer, approach, give, safety, refined, eating, rounding, leeward, farthest, hints, currently, noticeably, become, incorrect, cases, important, acting, future, unsure, stick, collect, brackets, rephrasing, believing, guess, snappier, kind, easily, remembered, buried, topic, reliably, least, mentioned, separates, suggests, great, picks, bow, looks, roughly, figure, okay, hmm, smoothly, pivoting, varying, difficult, mathematical, bearings, forgetting, old, general, tends, reoccur, rate, somehow, observations, judgment, chose, model, subtract, intuition, etc, reduces, terms, describe, decision, decisions, favored, tide, factors, blowing, avoid, risking, recommend, spending, anyway, convince, consequence, shorter, later, puts, sophisticated, version, result, fine, multiple, consolidate, obviously, never, transition, gradient, thermal, potential, matters, doesn, miss, harder, whereas, purely, recover, comes, hits, nail, head, moving, gradually, bits, pieces, trends, persists, directional, pauses, perhaps, throughout, free, contact, reality, conditions, significantly, slowing, hurt, ultra, sonic, marina, bvi, enjoy, point, rules, collisions, hauled, except, inexpensive, mere, completely, copy, minded, tactician, nannycay, searching, software, games, help, interesting, site, claims, windgame, homework, today, final, imagine, saw, overlooked, ignored, eggs, basket, pinned, magically, corner, banger, things, comparing, winning, pattern, its, length, importance, raced, justifications, talking, series, supposedly, resulting, thin, drew, square, ways, relative, present, differentiating, fluctuations, worth, noting, payoff, consideration, continuing, favoured, lateral, throwing, stronger, edge, keeps, ground, disadvantages, pressure, relief, train, both, sides, matter, puffs, dissipate, primarily, segue, alternately, half, making, benefit, secondly, roll, thr, ready, showed, partner, maura, strong, radial, uncomfortable, danger, encouraging, bang, corners, imagination, contexts, whichever, work, leave, affirmative, our, bearing, look, checking, although, exact, feeling, builds, forget, research, eavesdropped, channel, volume, pin, coach, overheard, conversation, looked, realized, barge, chestermere, cadboro, early, figured, coloured, veer, backed, aturally, fair, paying, attention, encounter, strange, colour, coded, legend, sorts, built, prairie, coastal, exclusively, victoria, water, conveniently, wouldn, presented, geometrically, arcs, circles, cover, aim, combine, data, monday, illustration, article, destination, design, website, pulled, situations, trick, identify, likelihood, capitalized, itself, waste, macro, placement, spent, rather, hope, recovery, enemy, runs, miracle, eat, loss, particularly, theoretical, change, form, vanish, reduced, susceptible, undesirable, subtle, sure, cash, impossible, pass, tell, clearly, screenshot, effective, removes, needs, closely, lines, northeast, returned, predicted, northerly, paid, got, crazy, shown, squiggly, faint, regard, their, building, idea, superimposed, tend, shots, races, show, hopefully, term, assumes, initial, noticed, tended, swing, evenly, farther, begins, west, patient, longsighted, impatient, speak, deciding, new, sets, deep, breaths, fingers, normalize, apparently, averaging, exceptions, approaching, seems, represents, calculates, reading, weekend, spring, heat, maximum, image, mine, found, consider, subscribing, https, speedandsmarts, destinationonedesign, index, aspx, dave, dellenbaugh, click, books, somewhere, supposed, passes, exceptional, yet, modeled, sudden, continuous,
Text of the page (random words):
h and continuous so how do you decide when is the time to tack during a smooth shift if you dig out your strategy books you should find somewhere in there that you are supposed to tack when the wind passes the median wind direction for example let s say that you are sailing on an exceptional shift you are very lifted pointing almost straight at the mark but then then you get a slight knock you are probably still lifted overall ie you are above your median so don t tack yet only tack when you have been knocked so far that you are pointing below your median heading because being below your median on one tack means being above your median heading on the other tack for a good illustration of how to tack on the median in a smooth shift check out this speed and smarts article posted on the destination one design website from which i pulled the picture below click here then follow the link how to play oscillating shifts by dave dellenbaugh at http www destinationonedesign com index aspx s how to play oscillating shifts this image is not mine i found it by following the above link please consider subscribing to speed and smarts if you like it https www speedandsmarts com order subscribe the above picture shows how a boat tacking on the median would make gains on a boat tacking on the maximum it is nice to be able to put this theory into practice by playing the sailracer net wind game immediately after reading it instead of having to wait for the race on the weekend or for the lake spring to heat up to put it into practice i don t know exactly what sail racer s algorithm is but while playing the game the instantaneous wind trace line and a damped down wind trace line are drawn out in grey the damped line is apparently averaging out the wind direction from the last little while with some exceptions like approaching laylines the sail racer algorithm seems to make the computer s boat tack whenever the line that represents the wind direction crosses this damped average wind trace line this essentially means that the algorithm tacks on the median but we don t know how the algorithm calculates the median i have noticed that for whatever reason that in this game the wind has tended generally to come back to north and to swing more or less evenly around the direction of north if i sail play the game with that information in the back of my mind my memory is going back much farther than the wind algorithm s memory so when there are longer phase oscillations and the game begins with the wind direction off to one side well to the east or west of north i am usually able to win by being more patient or longsighted than the algorithm the algorithm gets impatient so to speak by deciding that the current wind direction must be the new normal and so it sets it as it s median and starts tacking on it on the other hand i sail the lift to get inside the next shift that means taking deep breaths and waiting with fingers crossed for the wind to normalize back to north in the screen shots below i am the red boat and black is the algorithm i took a screen capture of these races because they show an example of playing the long phase oscillation as a persistent shift by sailing on the lifted tack and waiting for the wind to hopefully come back to north my long term median before the end of the leg the computer in the black boat blindly following the algorithm assumes that the initial wind direction is here to stay and that that should be the median looking more closely at the first screen capture you can see that when the race started the wind was already to the right of the rhumb line slightly east of north by looking at the grey wind trace lines i made a plan based on my theory that the rhumb line north was the true median the computer s boat black took the north northeast direction to be the median wind direction and so she tacked on the short phase oscillations thinking it was a neutral phase over the course of the leg the wind eventually returned to my predicted northerly direction so my strategy of treating this scenario as a persistent shift paid off i got well inside the long phase persistent shift however i want to emphasize that then crazy shifts came through shown by the squiggly faint wind trace line i tacked on them i didn t just blindly follow my plan with no regard for the short phases that were extreme enough to pay for their tacks this is what i have been building up to with these blog posts the idea that overall you may have a persistent shift strategy based on the big phase but superimposed on that you can still tack on the extreme oscillations that come through in the small phases as long as you get back to your plan as soon as possible and as long as your tacks pay for themselves remember the bit in the previous blog about how costly tacks tend to be in the first example where the persistent shift was more subtle i still tacked on the big shifts but i made sure to get enough separation from black to be able to cash in my left side advantage if my prediction came true when the prediction did come true i did not know exactly how long this big phase would last so once i had big paper gains i crossed back in front of the other boat then tacked directly to windward of her to make it more or less impossible to come back and pass me you can tell more clearly that i did the same defensive cashing in move in the second screenshot race this is an effective move not because of my wind shadow no wind shadow in this game but because tacking to windward of black removes leverage that she needs in order to gain or lose on wind shifts paper gains mean the theoretical advantage that you have if nothing changes until you have cashed in your paper gains because of your leverage a change in the form of a bad shift could make your gains vanish cashing in means reducing your leverage sailing ahead or behind your competition once you have cashed in you have reduced your leverage and so you are not as susceptible to undesirable shifts what i have been trying to illustrate is that in situations with combined long and short phase oscillations that is with real world messy persistent shifts you often have competing strategies to get inside the big persistent shift and to tack on the small oscillations the trick first to identify whether there is a high likelihood of a persistent shift that could be capitalized on next you need to get a feel for which oscillations are big enough that tacking on them pays for itself and which ones are a waste of time and leverage another thing to keep in mind is where you need to go next so that if you find yourself in a neutral macro phase you can act purposefully if you are happy with your placement on the course during the neutral phase you could spend your time tacking on small shifts if you are ahead your time in the neutral phase might be well spent cashing in any gains you may have by reducing your leverage if you have losses rather than gains leverage is your only hope of recovery and it is laylines that are the enemy as time runs out waiting for the miracle shift to get you back in the game in that case you could decide in the neutral phase either to eat your losses by cashing in consolidating your loss or to double down and go for more leverage another use for the neutral phase particularly at the beginning of the leg is to start executing the overall strategy that could be getting inside the persistent shift getting out of bad current or sailing to where there is better wind for example posted by ian e at 11 50 pm no comments email this blogthis share to x share to facebook share to pinterest monday april 6 2015 persistent shifts part 3 oscillating shifts in the first two persistent shift posts i presented some scenarios that were pretty much geometrically perfect but in the messy real world boats rarely sail on arcs of perfect circles so i want to take some time to cover oscillating shifts with the aim of eventually combine oscillating and persistent strategies in the next blog post and by following the link to the game at the bottom of this post we will get into using some real wind data in the below i have drawn the courses of boats a and b let s say they are sailed by prairie sailors from a small lake or coastal sailors who sail exclusively on a small bay in victoria out of the way of the current either way they find themselves on a big race course competing against the sailor in boat c who is more used to big courses on bigger water though conveniently still with negligible current boats a and b know to tack on the shifts why wouldn t you in this strange diagram i have colour coded the tacking angles of four different wind directions with a legend of sorts in the bottom right 4 degrees left four degrees right 10 degrees left and 10 degrees right i then built the courses of the three boats based on whether they were on starboard or port during which of the phases back stories and scenarios to make sense of this diagram i have made up some back stories boat a came out to the race course a couple of minutes early and figured out that of the two oscillating wind directions when the wind is in the direction that i have coloured orange it is a veer lift on starboard and when the wind is in the yellow direction the wind has backed port is the lifted tack in the time that a has been paying attention she does not encounter the red or maroon wind directions n aturally a starts on the lifted tack and every time a gets knocked she tacks fair enough b looked at the windward mark and realized that in the orange phase she was pointing closer to the windward mark on port so maybe b started on port or maybe she started at the barge on starboard and then immediately after the start she tacked onto port b would have been happy after the first shift when she was lifted onto the yellow course even closer to the mark but then when she was knocked back onto the orange course b tacked to stay in phase with the shifts so b continues tacking on the shifts which usually works back home on small courses on say chestermere lake or cadboro bay maybe c had been out on the course checking the wind for 45 minutes before the start which let her notice that although there are bunch of 6 degree oscillations that come and go there are bigger 14 degree oscillations that come and go more rarely c didn t need to know those exact numbers just the feeling of bigger and smaller shifts and a sense of where they come from so c builds a strategy that she should only play the big oscillations and forget about the little ones stay in phase with only the big shifts maybe c didn t even do 45 minutes of research with a compass maybe c just eavesdropped on the race committee channel that was playing at high volume from the pin boat or a coach boat and c overheard the following conversation markset are you happy with the position of mark 1 you look a little right to me affirmative we have been doing a wind trace and as well as some small shifts there are 14 degree oscillations perfectly about our rhumb line at this bearing good work markset then we will leave mark 1 there so c thought perfect oscillations about the rhumb line eh in that case i ll just try to stay on whichever tack takes me closer to the windward mark when i showed this diagram to my partner maura who is a strong radial sailor she was uncomfortable because she thought that i was in danger of encouraging people to bang corners for this reason i have not drawn in the windward mark with some imagination we could put this diagram and scenario in different contexts firstly we could have the windward mark just at the top of thr diagram with c on or just below the layline getting ready to round secondly we could say that the diagram only shows the first third of the beat and c continues on to cross a and b for another four minor oscillations before she tacks again on the next major oscillation in this case c would continue to make similar gains as the big phases roll through alternately if we put the windward mark half way up the diagram for a short course a and b would win because c would have to tack back onto the layline before making it to the big right shift that she had been calling for and without the benefit of having tacked on the small shifts segue about sailing in the middle of the course there are many primarily tactical reasons not to sail in the middle of a big fleet as a and b would have done with this strategy some of the reasons are that the combined effect of dirty air from many boats makes it generally slower if you are not well out in front puffs and shifts often come in from a side and dissipate and can t be used by the time they make it to the middle in the middle with boats to both sides of you no matter which way the wind goes lose to someone in the case of the above diagram especially the boats in the middle have tacked a lot in the diagram i have made tacks cost nothing but a and b have done 7 or 8 more tacks than c so in reality they should be even further behind in almost all boats in almost all conditions tacks are significantly slower than sailing straight unless the tactical gain from playing the shift pays for the cost of slowing down through the tack however in the above diagram you see that a and b s strategy actually hurt them even before taking into account the cost of the tacks to continue on with that train of thought for a bit a tack often has a double cost if you had been purposefully executing a strategy for example you had been sailing out towards pressure or out of some adverse current but then you tack on a nice shift after tacking on that shift you have to throw in another tack to get back to heading out towards the puff or current relief the cost of tacking can be even bigger if you bring in the tactical consideration that while you throw in this hitch tacking and tacking back the rest of the boats around you that didn t tack will be continuing out towards the favoured side this lateral separation on the race course becomes leverage against you if you are sailing towards a shift if you were sailing to a puff throwing in the hitch means you spend less time out in the stronger wind of the puff at the edge of the course if you were sailing out of adverse current the hitch keeps you in that current for longer so if you throw in the hitch it had better gain you a bunch of ground to pay for all those disadvantages the payoff to emphasize the slight difference in course position resulting from the different strategies in the above diagram at the top of the diagram i have drawn thin black ladder rungs i drew these ladder rungs perpendicular to the rhumb line because according to the race committee the course is perfectly square but there are other ways of thinking about the relative position of the three boats if we don t take the rhumb line into account and stay in the present we have the red ladder rung red for the red wind phase corresponding to the instanta...
|
