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

Originally posted by iGRF Mozzy, thanks for that, it was the clearest explanation so far as to your thinking and now I fully get it. It's not going to change my opinion in any way shape or form,

Determining whether a tide is favourable or not is quite easy. Working out whether it increases, decreases, backs or veers the ground wind is also easy as you don't have to know any precise values. I can do this very easily on the water with specific values or a vector diagram ashore. 

Mozzy, thanks for that, it was the clearest explanation so far as to your thinking and now I fully get it.

It's not going to change my opinion in any way shape or form, I'll still sail instinctively the way I've always sailed, but it's clear my thinking and the terminology you use are very different and I do find difficult to comprehend in reference to what happens in my real sailing world.

Everything you say (well almost everything and I can't quite work out how to prove the bits that I think are wrong)is correct, you do need to work out how to get to the bits of the course where the tide is either most favourable or least unfavourable, and preferably have a strategy to that end well before the start. But you do seem to contradict yourself one the one hand saying it's easy.

Originally posted by mozzy You're saying this as if it's soming difficult thing to do. It's pretty obvious whether tide is taking you toward or away from your next mark. And it's pretty easy to tell if the tide is adding, subtracting, backing or veering the ground wind to affect the true wind.  But there is nothing you can do with you boat or sails to change the above. So footing or pinching is useless by itself.

Then you say this

Originally posted by mozzy All you can do is focus on sailing to a part of the course where tide is more favourable.  This is the hard bit and where interesting discussions may happen, which we never get to on this forum because you bog us down in your stupid pinching or footing stuff.... you know, like whether it's worth the loss of tack to get in to better current, or sailing a slower VMG mode to get to better current quicker. Or ignore oscillating shifts and sail a few short phase headers to get to better current.

To which I'd say ignoring your jibe about my stupidity, that it's been my experience that if the tide is a consideration it's generally due to light winds and lack of air power, it is also less likely to oscillate unfairly so I'd tend to ignore fast oscillating gain/losses in favour of the bigger potential of the slower oscillating tidal gain, if one were available. Would I foot off in order to get to it, would depend on the size of the course and of course wether I was not just footing off in the air supply but the current as well which I probably wouldn't but there I go again me thinking that the angle of attack of my sub surface foil against the current makes any difference whatsoever and on that I fear we are going to have to differ. I wonder if it would help your thinking if you tried sailing a sailboard? (Not a frivolous suggestion, you might quite enjoy it and learning to use the 'feel' instead of instruments, just like Luke Skywalker fighting the drone with the blast shield down )

Finally

Originally posted by mozzy On the water it is the above mental calculations I find impossible to do with any certainty, not least because without instruments it's impossible to be certain of the inputs. You're estimating half the inputs and imagining the vectors then ultimately making a guesstimate of what the gain might be and what your VMG loss would be. And on the water you often have to make these decisions in seconds as clear air lanes open and close on the course around you. That for me is what makes sailing fascinating, infuriating but ultimately great...

Something we can agree on and are equally passionate about.

Originally posted by mozzy but instead we have 25 pages of just going round and round with your flat earth theory.

Yes, isn't it fun? And I've learned something from it, which is a valuable thing in itself, spreadsheet and accounts software dodging to boot.

Edited by iGRF - 02 Oct 19 at 10:33am

Well said Mozzy!

Originally posted by mozzy was that a first sign of some moderation in these threads... or was that post by GRF a figment of my imagination brought on by PTS?

Why would you want moderation Mozzy? Because the opinion differs with your own?

Truth was I had a moment of clarity and can now fully understand how you are all so wrong headed imv, following all those posts, was half way through working on an equation to illustrate my view point but the phone rang and business took over I posted it it before I'd fully thought it through and finished, so deleted it, then thought why waste your time anyway.

The moment has gone now, so all I'd leave you with is the thought of how a GPS might have helped or hindered our young windsurfing friend. How the knowledge that what he did was 'wrong' or mathematically impossible?

Maybe the maths don't work the same for windsurfers, we don't have instruments after all and can only use our instincts and the force. It is certainly true that footing off in an unfavorable tide will kill you every time, it is also true that getting the tide on the lee side immediately increases the sensation of power through the rig because you can feel it. In certain circumstances that increase in tidal power can induce planing and an exponential speed increase that will absolutely destroy the footing off fellow. My post was requesting that someone smart enough could work on an equation that might illustrate that, it may even exist in naval architect school.

But you cannot rely on half those illustrations above in our world, they may work offshore, I'm not even sure they are true in light dinghys. GPS cannot define true wind unless it's connected to a land based sensor. I can only assume that it calculates apparent wind from an algorythm, difficult for me to argue against as I've never experienced one other than as a device to measure ground speed at speed trials etc.

I also suggested in the deleted post that the term 'tidal wind' was confusing, since it really is a misnomer in anything other than completely still situations, the rest of the time it is simply a contributor to or reduction factor of the actual or 'true'wind ultimately affecting the 'apparent or virtaul wind' which in itself is varied hugely by the created wind and that varies according to the drag coefficients of the particular size and weight of the hull.

So my proposal is that we should find some common ground on areas that we do agree on.

One of those must be to accept that sailing with tide adding to the wind power is better than the opposite.

Then, there needs to be a defining calculation going from 180 degrees opposite, to 0 and work out at what point in a given style of craft that it ceases to be positive to our goal.

So rather than arguing round and round we achieve some goal from all this.

Edited by iGRF - 01 Oct 19 at 7:21pm