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  1. #1
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    Apparent wind in onshore waveriding

    Yes, this is complicated and I can't guarantee that all I say below is correct. Constructive comments held in a nice tone are welcome.

    I'm not going to explain the concept of apparent wind (a function of true wind and the wind created by moving) in any detail as it's better explained elsewhere and the math is anyway above my head. Two observation may help understand what happens when we go frontside on a very onshore wave. The first is that fastest point of sailing on a windsurfer (on flat water) will be a broad reach. The second is that when heading straight down wind the created wind cancels out the true wind at a rate of one to one. Exactly what happens in between I can only guess. But it seems likely that the gain in apparant wind from boardspeed will taper off as you keep bearing off. And that at some point before down wind it will start working against you at an increasing rate.

    So where is this leading? Imagine that you're sailing along a very onshore wave (say 30 degrees) while waiting to drop in. You're going slowly while pointing relatively high. At the right moment you pivot onto a broad reach and drop down the face. If the wave is any good you'll pick up speed which then adds to your apparent wind. The challenge now is not only to exploit this virtuous circle by picking a good line on the wave and sheeting the sail for maximum drive, but also to sense when it's time to really tighten the turn and power up clew first back up the wave.

    Partly based on experience and partly on (over?)thinking, I believe it's easy to delay the bottom turn for too long. (Beginners sometimes actually start too early with too little speed and just dig into the wave face.) One example is based on a recent experience. I managed to catch a number of relatively steep waves (lumps rather than lines) on a big combo in pretty light winds. What struck me was how the board tended to loose speed in the bottom turn (I still made the top turns) despite its width and float. What happened I guess is that the apparent wind decreased very quickly as the true wind was weak and also partly blocked by the wave. So tightening the turn sooner could perhaps have been a good idea?

    Turning harder/sooner may however be a good idea also in strong conditions. If you manage to generate good speed before heading straight down wind it will partly cancel out the true wind and allow you to turn tightly without too much power in the sail. Think of the part from just before to just after downwind as a "slow go zone". If instead you turn more leisurely heading further dtl the apparent wind is soon likely overpower you. (It's similar to the mistake people do when gybing in strong winds. Rather than push on the hips to complete the turn swiftly they wait and then get overpowered.) Handling huge amounts of power clew first is not easy. But if you drop your hips well to the inside and keep your arms rather straight you can complete the turn early and go vertical rather than fly dtl and get hit from the side. Ouch!

    In earlier comments to threads on onshore riding Basher has often understated the need to open up the sail clew first if you can generate good speed on the wave. Probably like most others I've half nodded to this but haven't really been convinced. While opening the clew normally amounts to sheeting out, the reverse is true when actually sailing clew first. The more you open the sail (by swinging it out of the turn and back on straightish arms) the more you're actually sheeting it in for the way you're heading. And with more board speed and therefore the apparent wind more on the nose you'll need to open the clew even more to avoid backwinding. Not less! I recently noted Basher saying something to the effect that the apparent wind won't help you much in onshore conditions. (Quoted below.) So perhaps he's changed his mind?

    "Maintaining speed down the line on a windsurfer is in fact about taking a fast line along the wave and travelling at a speed that keeps apparent wind on the nose so you can stay sheeted in if possible.
    In onshore conditions this gets more difficult and it usually helps to have enough float under your feet, and it also helps to have a fast rockerline that suits the wave shape."
    Last edited by boards_Tomas; 4th October 2017 at 09:47 AM.
    The infamous wavewriter

  2. #2
    dear oh dear oh dear.
    Now back in the UK.

  3. #3
    Let me give you some basics first.

    Wind angle on the wave varies from place to place, so there's onshore and then there's really onshore.
    The wave size and wave power also vary from place to place.

    With a big clean wave you can surf a windsurfer even without much wind. On a big wave you can also be blanketed from the true wind – if the wind is coming from behind the wave.


    What is apparent wind? It's the wind you sheet your sail to, which is a mixture of the real wind of the day, and the created wind – usually created by your board speed. So when surfing a wave the created wind runs along the board, opposite to the way you are going, and that combines with the true wind of the day to make up apparent wind which is in a new direction and sometimes with added strength.
    Remember too that the wave itself is moving you towards the beach so there are in fact two 'created winds' in addition to the true wind of the day.


    So this gets complicated. In onshore conditions the point at which you open up the sail (to go clew first) will vary according to wave power and according to the speed you can achieve with your wave ride. That speed will depend on the board you are on (in terms of float and rockerline), and on the line you choose to sail along the wave.

    So you might find that some sailors can stay sheeted in longer when cranking their bottom turn, whereas others sail along the wave clew first from very early on.



    The important thing about apparent wind is to get your head round the concept of it. But on the wave face, forget about it, and instead concentrate on getting speed along the wave and then sheet your sail to the wind you feel.



    It's interesting to me to watch PWA wave sailing at Sylt today. The wind is more onshore than I would launch in, so the sailors are having to go clew first, and they are having to stay high on the wave to keep any real wind in their sails. If they drop in front of a bigger wave then the wind goes from their sail and they quickly get rolled by white water or a close out wall. It looks crap. Most of us would drive somewhere else to sail.



    As all waves are different in this respect, it's so difficult to talk about this on the printed page.
    Watch the PWA livestream from today!
    Listen to the commentators when they talk about when to 'go early' and when to 'go late'. Watch the sailors try to find clean sections, whilst having to dodge waves when necessary.
    What we can say about Sylt is that the sailors don't get much help from the waves because there's not much face to create speed with. The wave itself pushes you towards the beach negating the true wind. This is why we are seeing very few fluid wave rides today.
    Last edited by basher; 5th October 2017 at 01:36 AM.
    Now back in the UK.

  4. #4
    Senior Member Silicon Beach's Avatar
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    Quote Originally Posted by basher View Post
    The important thing about apparent wind is to get your head round the concept of it. But on the wave face, forget about it, and instead concentrate on getting speed along the wave and then sheet your sail to the wind you feel.
    Yes, and also as Ola says: concentrate on surfing the wave. I know his tip is OT (about wave power rather than wind, apparent or otherwise) but for me it is crucial. I find that if I focus too much on the rig and what the wind is doing I lose the 'bigger picture' of what the wave is doing.

    As Basher says apparent wind theory is fascinating stuff, but real world wave riding is really all about maintaining speed on a wave. If you have it then the rest follows (stylish bottom / top turns, throwing spray, moves like 360's, takas etc).
    -----------------------------
    Currently writing the World's first Windsurfing Novel: 'Too Close to the Wind' - watch this space!
    ps check out my musings from El Medano: Life on the Reef
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    Boards: Quatro Supermini Thrusters: 94 & 85
    Sails: Severne Blades.

  5. #5
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    I always talk about REALLY onshore conditions. Nobody can possibly have avoided noticing that. And I'm really just making some simple observations about how changes in the apparent wind can help or hinder you when you go through a full toeside turn.
    Firstly when dropping in, your boardspeed will add to the apparent wind so make good use of those two seconds with maximum drive in the sail as well as push from the wave. As you turn through downwind the boardspeed will tend to cancel out the true wind and so it's time to turn. Make it a tight one! Since you need to turn through downwind before hitting the lip you'll have to open the clew up. (No amount of board speed can change that fact unless your surfing a very big fast wave. But you'd still have to open the sail at the top to avoid backwinding.) Just like the apparent wind worked in your favour when dropping down the wave it will be back with a vengeance as you turn through downwind and start heading back up clew first. You may not go quite as fast. But on the other hand you'll need to handle the power clew first. So getting most of the turn completed and also getting sail and body in the best position to be able to drive the board back up the wave, is essential. My ideas about that should be well known.

    Late edit after reading SBs comment: Surfing the wave is of course also important. As is finding a good one in the first place and dropping in at the right time. But explaining stuff like that is even harder than to outline some basics about rig handling. Also listing all and every factors that governs a waveride like Basher does, may seem clever. But it's not helpful. Basher's the one that have repeatedly been bringing up the subject of board/wave speed and how that affects the need to open up the clew. But his (earlier) point isn't valid when it comes to really onshore conditions.
    Last edited by boards_Tomas; 4th October 2017 at 04:22 PM.
    The infamous wavewriter

  6. #6
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    My biggest tip for really onshore wavering is to go and do something else, it's rubbish, end of. No really don't bother
    2017. Wave sessions 19 Bump Jump 14
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  7. #7
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    Thankfully I didn't read Jamie's post before writing the below. Because I
    strongly recommend that people put in a real effort to learn to go frontside on really onshore waves, and even if it's just single smacks. You can do that almost everywhere and the skills you build will be very useful whenever you get a slightly better wave or angle.

    Speaking of angles I did some wavespotting today. Technically speaking it was actually sideshore. And the biggest lumps where well above three meters and could easily take you down and over the rocks. As I was also alone I decided to climb a big rock (you know the one that always half blocks the wind when it's blowing sideshore) to get an overview and perhaps take some photos. What I saw was a lot of water moving around and some huge splashes. The period was up to about eight seconds so not a problem by itself. But the wavefaces were generally flat, choppy and unpredictable and tended to crumble from the top before really getting steep enough to make a good bottom turn. I did in fact not see a single wave face that I wished I had been on. So no gain just pain, I decided after watching for about half an hour. I've been there before and holding on to your gear when those big lumps crumble is often just too much And when you let go you'll see your kit on the rocks and must expect serious damage. Been there.

    So unless you live somewhere with very favourable natural conditions for dtl windsurfing you can either give up the idea of frontside waveriding altogether or learn to swing the rig around like I teach. You can of course still have fun in the waves without going front side. Finding a shoulder to jump will be much easier than finding a waveface to drop down. I regularly sail with people who jump much more and much better than myself, who throw in freestyle moves and ride backside. But for me going frontside is all that matters. I actually find it quite safe in the right conditions. The benefit of being a one trick pony is you stop making mistakes. For old ponies that's important.
    Last edited by boards_Tomas; 4th October 2017 at 05:19 PM.
    The infamous wavewriter

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