Tactical 'Pop' Quiz
Printed From: Yachts and Yachting Online
Category: General
Forum Name: Banter
Forum Discription: For all those non-sailing related discussions
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=5301
Printed Date: 16 Aug 25 at 12:15am
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com
Topic: Tactical 'Pop' Quiz
Posted By: G.R.F.
Subject: Tactical 'Pop' Quiz
Date Posted: 13 Mar 09 at 10:40am
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So Ladies...
What is wrong with this statement as printed in that font of all knowledge tactical DSM...
------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |
Replies:
Posted By: NeilP
Date Posted: 13 Mar 09 at 1:03pm
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I can think of several things, which one did you have in mind? The possible tidal lee bow, the confusion over shifts or bends.... GRF, have you been naughty and taken a statement out of context, by any chance? ------------- No FD? No Comment! |
Posted By: G.R.F.
Date Posted: 13 Mar 09 at 1:08pm
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I dont think so, go and have a look, I've asked a question for clarification.
Just another example of lack of tactical expertise at high level 'youf' now lecturing us in print. And yes, the tidal leebow consideration, the effect the tide will have on boats already rounding the mark forcing them deep, to name just a couple. Not to mention the overstanding effect the tide will have on those coming in from the right hand lay line. ------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |
Posted By: Roy Race
Date Posted: 13 Mar 09 at 3:09pm
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Not an awful lot wrong with it. The article is about the
final approach to the windward mark, not the strategy for the whole beat. If the current is flowing left-to-right, I'd be looking to avoid getting on the starboard layline too early at all costs so "approaching from the left" is a fair call, I'd say. "Oscillating wind shifts are in the main bending in from the left". That's just a badly-worded description IMO. But if there's a strong chance of the next shift being a lefty, then yes, of course that'd also support going up the last bit of the beat left-of-centre. I can't spot too much wrong with it. |
Posted By: NeilP
Date Posted: 13 Mar 09 at 3:25pm
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I have to agree with GRF if he hasn't taken this out of context. The layline isn't the issue anyway. Regardless of any other considerations, why would you ever hit the starboard layline early? All that acheives is to leave you trundling along in a queue with absolutely no tactical options. There is also the issue that if you know the tide is left-to-right, the leebow on the starboard layline will get you in under all the muppets who've overstood because they didn't know. Final point - if you're writing in a professional capacity in a publication, there is no excuse for ambiguous or downright wrong use of english. Read that windshift bit again. What does it actually mean? Answers on a postcard please ------------- No FD? No Comment! |
Posted By: G.R.F.
Date Posted: 13 Mar 09 at 3:45pm
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Well all the strategy I would have planned for a beat in circumstances
described would be an early lee bow off the line (fundamental imv) on Starboard from the Port end, then if lucky enough to meet a significant knock bang over early for the requisite time making sure not to go too down tide and certainly nowhere near the starboard wind based layline, then another final leebow up to the mark coming from shallow right. Under no circumstance would I be on either wing if it was shifting around. ------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |
Posted By: NeilP
Date Posted: 13 Mar 09 at 5:38pm
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Oh God, what am I going to do now???? Admittedly it's not the most complex strategy problem, but GRF's right on the money. I have to agree with him again! As a result I can never hold my head up in decent company again, and will have to do the decent thing... (Footsteps off, muffled gunshot) ------------- No FD? No Comment! |
Posted By: Inland sea
Date Posted: 15 Mar 09 at 10:09am
Good stuff their thanks ... but the lee bow bit is a Braithwate for me (whooosh over me heed  ) Could you clarify please?
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Posted By: alstorer
Date Posted: 15 Mar 09 at 5:36pm
Someone will be along in a moment to claim it doesn't exist. ------------- -_ Al |
Posted By: G.R.F.
Date Posted: 15 Mar 09 at 7:37pm
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Had an argument once about tidal lee bow, with an Olympic coach, he
didn't get it either and very rudely and abrubtly halted the lecture I'd been giving his squad on the subject of tidal courses, startlines and the various strategies best taken to deal with them. Many year later I had the good fortune to spot him 'coaching' the then Olympic squad as to the best strategy to approach a particular course and incoming tidal scenario over a long distance race. His opinion as to the correct approach to the tide and a wind bend over the cliffs and how and when to deal with it clearly sketched on a white board for all to see. My view was exactly opposite to his advice. I wasn't actually going to enter as I'd only been there to watch, but it was to tempting to resist, so I did, went for the 'other' cliffs and sailed the four mile beat with the incoming tide full on my lee bow. When I got to the windward mark, he and the rest of the Olympic Gravy Trainers were there in the support boat, their 'squad' yet to arrive, barely visible as they, followed by the rest of the fleet, were sailing up tide on the wrong side of the beat about ten minutes behind tide now squarely on their weather bows. Leaving them to face the most delectable rant from a 48 yr old retiree on the merits of volunteers driving all the way to Weymouth at their own expense to offer tidal lectures to young Olympic aspirants and how best they should be given the chance to listen next time and how much longer did they think it would be until they caught up. Funnily enough I've not been invited back. 
So yes, tidal lee bow is often of more overiding import than some windshifts particularly in sub planing circumstances given the increased boat/board speed and better VMG achieved when it's favorable. ------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |
Posted By: simsy
Date Posted: 15 Mar 09 at 9:00pm
Nice story. I don't suppose you'll name the coach? I can understand if you don't. I think the original statement is very generalised, and yes, the wording is very poor. However to 'claim' one particular way to go is the right way, is very misleading without taking a lot of other factors into account - which they clearly haven't. |
Posted By: Medway Maniac
Date Posted: 16 Mar 09 at 10:14am
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I'm confused. The article recommends sailing up the left side of the beat (which among other things means avoiding the stbd layline). GRF says he'd start on starboard tack (i.re. going left) - isn't that the same thing in principle -you're both avoiding going right, which with a necessarily flexible strategy in shifting winds is the most you can set in stone, isn't it? Mountains, molehills? ------------- http://www.wilsoniansc.org.uk" rel="nofollow - Wilsonian SC http://www.3000class.org.uk" rel="nofollow - 3000 Class |
Posted By: Mark Jardine
Date Posted: 16 Mar 09 at 10:48am
| I remember an argument on Scuttlebutt a few years ago about the lee-bow effect. There were some 'scientist' types on their claiming it didn't exist - wow did that turn into an argument and a half! |
Posted By: G.R.F.
Date Posted: 16 Mar 09 at 3:18pm
Er when are we going for that race again? Not sure if I should write this, dont want to go giving a river man clues 
The bit I took issue with was approaching the windward mark with effectively the tide on your weather bow, by coming in from the left late. Yes I'd go left, but it would be middle and left with as much time spent on starboard as 'tempting' knocks would allow. but my final run would be on starboard having understood enough for the tide to lift me the last bit. Not banging in from the left with the risk of whisking by, tacking and overstanding even further, if I wasn't ahead further putting myself at the risk of early rounders being carried down on top of me or at the very least adding wind shadow to the already eroded windspeed the tide was dealing.. Clear enough now? ------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |
Posted By: Adam MR 1137
Date Posted: 16 Mar 09 at 3:35pm
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As a river and pond sailor mainly, I struggle as soon as I have a decent amount of tide to try and figure out. So this disscussion was a little lost on me. I was reading in the hope that it would suddenly all make sense. Although not quite as epihany like as I need, the above post did help me understand why GRF was choosing the course he was due to the tidal effects. So thanks a lot for explaining, it has helped me understand a little bit why every one else is so far ahead at the windward mark when I race on the sea! ------------- Merlin rocket 1137 OK 2049 Can be seen at http://www.wellandyachtclub.co.uk/ - WYC |
Posted By: G.R.F.
Date Posted: 16 Mar 09 at 3:59pm
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Well it's always a difficult one, and I've never seen a definitive calculation
written, but as a rule of thumb, lets say 8knots wind and 4 knots tide left to right. So your sail is being driven by 8 knots true and then whatever created wind your particular craft is capable of which produced the apparent wind your sailing on. So basically going one way a percentage probably 50% of the tides speed providing your bow gets a sufficient angle against it assists the 'created element of the wind that produces the apparent wind and going the opposite way, it degrades it. So the boat travels not only physically faster through the water that is flowing say 10 knots of combined speed 8 from the airspeed and two from the tide and 6 knots air speed the other way, and because the created element of the wind is stronger one way it also enables the boat to appear to point higher, whilst not being able to point as high on the opposite tack. (I'm guessing at what level the speed of current contributes, it would vary according to the precis angle it lifts the foil at I guess 50% at 45 degrees no doubt some maths head could elaborate.) Anyway, maybe it's more noticeable for us on Boards (the displacement speed type), but it's been my experience that it most certainly has a similar effect on the boats I've sailed to date. It needs sketches and angles to explain thoroughly, I'm available for lecture tours (that's a joke, me lecturing dinghy sailors could you
imagine it ) Eric Twiname covered it I'm fairly sure in Start to Win..------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |
Posted By: Roy Race
Date Posted: 16 Mar 09 at 6:08pm
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If the strength of the current is the same on all parts
of the course, then it makes no difference. I agree 100% that the lee-bow tack (starboard) is the peachy tack (pressured and lifted) but it makes no difference whether you do it beginning, middle, end or wherever on the beat. The differences you mention - "Yes I'd go left, but it would be middle and left with as much time spent on starboard as 'tempting' knocks would allow." - are just windshifts, which would apply whether there was tide or not. The really important part with lee-bow tactics come with differences in tide. The golden rule is: DO YOUR LEE-BOW TACK IN THE STRONGEST TIDE. So if the tide (left to right) is stronger in the last half of the beat, go right. If it's stronger in the beginning, go left. If it's the same up the whole beat, it has no effect, because you have to do the port tack at some point, wherever you do it. The only thing you have left to work with is windshifts. |
Posted By: tack'ho
Date Posted: 16 Mar 09 at 6:10pm
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Arrrhhh, you see there's the confusion that's simple vector logic. now if the tide and wind were equal all the way acroos the race course it wouldn't matter which way you went, cause assuming everybody hit the layline and went the same speed it would be irrelevant (you'd spend the same time on each tack regardless of the order you did them). What I believe your saying is you need to be on the appropriate tack at the appropriate time to suit the variances in wind and tide across the course. ie. minimise your time on the bad tack and maximise on good! ------------- I might be sailing it, but it's still sh**e! |
Posted By: tack'ho
Date Posted: 16 Mar 09 at 6:19pm
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oohhh spooky...what he said!!!
------------- I might be sailing it, but it's still sh**e! |
Posted By: Roy Race
Date Posted: 16 Mar 09 at 6:28pm
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Absolutely.
Another layer to this should be that you need a good reason NOT to do the longest tack first. In this case, if the w/w mark is dead upwind (true wind) and the tide is flowing l to r, then starboard becomes the long tack. Doing your short tack first quickly narrows your options and puts you into a corner. But yes, if wind and tide are constant up the course, you have to do both tacks and it doesn't matter which order you do them in. Of course, wind and tide are very rarely constant up the whole length of the course! Edit: Oh, I see! Tack'ho was replying to GRF, not me! Yes, what he said. |
Posted By: bert
Date Posted: 16 Mar 09 at 8:26pm
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This is a bitch to understand as a pond / no tide sailor IE me.
BUT drawing out the situation on paper really helps to understand the discussion because when you are sitting on the water it is hard to realise what is happening to you when it is oblivious from the club house. It`s also a situaion that I always fail to realise untill it`s to late when it`s happening & so it`s worth while to make time to look at the lay of the water & tide to see what you should expect before getting the boat out.
However this is an excellent discussion & is quite easy to follow & understand.
Thanks GRF.
Can we expect a DVD? ------------- Phantom 1181 AC-227 IC 304 blaze / halo 586 |
Posted By: G.R.F.
Date Posted: 16 Mar 09 at 9:42pm
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Er...
This could develop into a full blown chapter. I always maintain it does matter. Take the lee bow early and only the weather bow on favorable shifts. I also always used to suggest the length of the startline is very important and how far down tide the favored end might be in relation to the time duration of the beat. Depending on those calculations, is how long you get to stay on the favored tack, enhanced by how far down tide of the start line you position yourself at the gun. Extreme circumstances can produce a one tack beat when the wind has dropped for example and all the boats from the none favored end sailing high and relatively fast lay the mark bang on whereas those at the favored end find themselves having to free off further and further going slower and slower with the same effect of being the wrong end of a 'knock'. Extreme, but it makes the point and has happened to me over the years enough times to cover for. Yes you should consider the tide as a conveyor belt and everyones position relative to each other remains equal, but factor in time and reduced wind and some can find themselves more 'equal' than others in relation to fixed mark positions has often been my experience as has travelling faster earlier rather than having to pay catch up later.. ------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |
Posted By: Roy Race
Date Posted: 17 Mar 09 at 7:15am
So far you've said you'd do the lee-bow tack late...
and early...
Can you clarify whether you would do the lee-bow tack early or late or both? What if there's a favourable shift right at the start? What's a "final run"? 10 yards? 100 yards? It's worth pointing out that everyone in the race will do a "final run" of some duration on starboard if it's a port rounding. I still maintain that what you're advocating when you say "...only the weather bow on favorable shifts" is nothing more than "play the shifts", a strategy with which I wholeheartedly agree. |
Posted By: G.R.F.
Date Posted: 17 Mar 09 at 10:19am
Personally I'd always go for the lee bow tack first, wether it was left or right for the reasons I made earlier (you never know how things will pan out later in the beat). (Even more important if the tide is going right to left for example simply because with the majority of the fleet on starboard, manage to get out the back door right early, nine times out of ten you'll nail them simply because the starboard nature of the majority forces them way down tide and they over stand on the way back.)
I might well ignore it, depending on my calculations regarding the start line length, course length and time duration and how much left to right tide I'd be expecting. A favorable shift (lift at the start)could see you massively over standing if you were already at the pin end.. Alternatively a genuine favorable shift which of course I take to mean a massive header shortly after the start with me down the Port End I wouldn't obviously ignore and would probably knock the tide off the lee bow anyway, that I couldn't ignore.
The last 25 % of the course give or take. How can you totally qualify it? For that course my strategy would have been to try for.. First 25 % Left, mid 50% middle and left but trending ever right, and final approach right, and short of the lay line getting lifted by the tide. But of course events can occurr, but overiding everything the fundamental rule is always Take the tack that's taking you closest the mark and if the tide is assisting that tack all the better. ------------- https://www.ease-distribution.com/" rel="nofollow - https://www.ease-distribution.com/ |
Posted By: Medway Maniac
Date Posted: 17 Mar 09 at 11:52am
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I still think you're all (including the DSM guy) saying pretty much the same thing. Go left, use the shifts and finally come into the mark on starboard like we all do unless we're feeling suicidal or the fleet is thin. Still, thanks, it's always good for us creek-dwellers to get our heads out of our banjos once in a while. ------------- http://www.wilsoniansc.org.uk" rel="nofollow - Wilsonian SC http://www.3000class.org.uk" rel="nofollow - 3000 Class |