Lee-Bow..... Windsurfers...etc (Dons tin hat)

Regarding the 'cliques' and I certainly don't purport to be in any of them other than the 'village idiot' that I can't deny having been more often than not. But this subject has entered a realm within which I can claim expertise, hence the more measured approach.

This doesn't mean I'm not going to continue to be the provocative 'idiot' in future threads concerning that area where I have self confessed lack of expertise and have been here to learn as well as amusing myself often at others expense.

The problem comes of course when having obviously been 'an idiot' more often than not, who's going to take your word when you try to act seriously? So, unwittingly that puts others at risk if they concur with my view and that sadly may have happened to H2 and others who may have supported the view. So for that you'll have to accept my apology.

Both Mozzy and Peaky are clearly far more mathematically and technically minded, what is it right brain over left? My thinking is always more left field than most, always has been, but in this instance my experience says they are wrong, proving it however has been difficult in extreme, then I read that mathematical theory of sailing document and way bigger maths brains than my own have been struggling with definitions for years of aero&fluid dynamics and lift, I also came across a couple of calculations regarding VMG that to my mind are very questionable. I always prefer to keep an open mind, I accept my terminology in this is dated, I also accept the debunking of 'lee bow effect' but lee bow theory cannot be debunked. The issue of pinching is the remaining bone of contention I can also see why this is so, you do lose VMG if you pinch and nothing happens as a result, but I maintain if the act of pinching become 'heading up' and a tidal lift and increase in created wind occurs then it's not pinching.

Oh and Ferry Gliding clearly is a 'thing' as well.

Edited by iGRF - 03 Oct 19 at 10:08am

Originally posted by 423zero Mozzy, You are one of the more knowledgeable posters on here, not calling you, well I am not anyway, your video section brilliant.

Originally posted by Old bloke iGRF, I don't think anyone disagrees that ,when the current is with you ,and under your lee bow ,and when going to windward, the boat is pushed to windward with a subsequent increase in the wind that the boat experiences. Its the heading into the tidw and thw claim that that is somehow powering up the foils that is the problem

Well let me highlight the issue like this then and I watch lots and lots of dinghy sailors do this.

Sailing upwind off the start and the wind begins to lift, should you head up? (Lots don't because they don't appear to spot it as soon as I might, maybe they are not watching their tel tales, the flag thing some boats have on the mast top, or their wind indicator, but they very often don't)

The answer very obviously unless in doing so it means you've got to sail away from the mark, is yes of course you head up.

So my view is that heading up a bit more in a tidal stream is exactly the same as heading up in a lift in that the increase pressure of moving the current from either weather side or head on, onto the lee side of the foil in fact induces a lift*, hell I've even seen it referred to as a tidal lift.

Now, tell me that's wrong.**

This thread remember is more about the windsurfer son of the OP, windsurfers 'feel' their lifts and headers it's their principle means of detection and that chap in question railed up and induced a tidal lift, maybe the others missed it, maybe the entrance bent away and made it easier, maybe the wind lifted in order that he could get more pressure on the lee side, but that is what happened and it is very much a 'thing' that 25 pages of bullsh*t cannot deny.


*Now the facts that support the lower foil inducing lift are in that paper I referred to and are part of theories of fluid dynamics, foils induce lift, changing the attack angle also induces lift, the attack angle of foils is narrower than the range of most sails, another fact. How many facts need to be reeled out?

**I can discuss lots of instances when taking a lift might be wrong in boat on boat tactical racing in fast oscillating shifts, but that's a totally different discussion, this is a tidal illustration




Edited by iGRF - 03 Oct 19 at 9:44am

I posted an opinion early on in this post and was clear that it was something that I had only experienced once and gave the background to what I assumed had happened - I did not claim it was anything but a rare occurrence that I was trying to understand. The reaction I got struck me as extreme at the time so I tried to engage in the discussion but soon got pretty turned off by the tone of responses so I just tuned out. My experience of the forum has been that if you are not part of the little clique then you are viewed as an idiot, which may be true.

iGRF, I don't think anyone disagrees that ,when the current is with you ,and under your lee bow ,and when going to windward, the boat is pushed to windward with a subsequent increase in the wind that the boat experiences.
Its the heading into the tidw and thw claim that that is somehow powering up the foils that is the problem