Sailing in tide..quiz.

Edited by mozzy - 03 Oct 17 at 11:25am

I'm not sure why he (the coach) sent them so far along the coast, I often wonder wether he might have had a nightmare experience at Portishead (Windsurfers used to sail there every year) and if you want a truly aw (ful or some) tidal experience, try sailing there, I swear to God at some stages of the tide if you lassoed a fixed mark you could waterski behind it.

But one of the things about Portishead they used to set a wing mark right out in the channel and if you didn't beat far enough up the bank and set out for it too soon, you'd never be seen again.

Getting back to the energy thing again, something back there someone said was wrong, inland on a lake, there are only the two components, the true wind and the created wind which only happens once the board/boat moves and they combine, so there is nothing else for the boat and it's foils and the wind to 'know' other than the static water we sail on.

The boat or it's foils don't 'know' anything on the sea either, the thing if anything that 'knows' the difference is the true wind which reacts against increasing or decreasing resistance from the water because it also is flowing either with or against the strength of the wind and so delivers more or less energy to the foils.

Edited by iGRF - 02 Oct 17 at 11:00pm

Originally posted by iGRF Originally posted by sargesail Originally posted by iGRF So this is actually what happened. Blue arrives at island before red tacks to cross channel. OK - so talk me through the curved laylines.  Why does blue gradually get lifted on port? Why does red gradually get headed? And where can I get one of these windsurfers which point so high that the tacking angle looks like 40 degrees? The curve indicates the strength of the tide 'lifting' the board higher, tidal lee bow, as classic as that, is twofold, not only does the board physically go faster thanks to the energy provided by the tidal flow, but the direction in which the tide is headed lifts the craft upwind. The reds stayed out of the tide. You can buy race boards for next to nothing on eBay and I'd strongly recommend any sailor trying one out if for no other reason, than to actually feel all that knowledge you obviously have, in the palms of your hands, you'd find it exhilarating.

Originally posted by mozzy Okay, I get what you're saying. But I don't think you're phrasing it very well. The true wind over ground, plus the tidal vector = the wind you feel if you were floating stationary. Depending on direction the tide will shift, add to, or decrease the true wind (from what is experienced on land (or moored up).  But, in the boat, you can't feel that. the boat can't 'feel' that. All the energy comes from the sheer between air and water. Those two things, nothing else. Whether it's just the air that's moving (lake) or air and water (sea) it is still just the sheer between the two.   Also, you'd still not explained the 3rd point of tide hitting the foils etc etc.

Originally posted by iGRF Originally posted by sargesail Originally posted by iGRF So this is actually what happened. Blue arrives at island before red tacks to cross channel. So tell me why it wouldn't have been faster for blue to do a hybrid of the two: short tack like red and then do a starboard leg from the end of the headland until meeting the port layline drawn? Pretty much what we'd been doing earlier in the week when the windward mark was sited just at the tip of that left arrow. The main reason to go left (as also pointed out by Mozzie, credit where it's due) was the likelihood there would be a better lift off the opposite cliffs, which would get the nose into the tide earlier than rounding the headland where the lift off the land petered out, quite why they didn't harden up to head out to sea I'll never know, they were not stupid, some were Hayling sailors so not tidal neophytes, but then again who knows what squads have to do when their coach is dictating the route. I didn't win the race, I spent too long berating the coaching team who were moored at the island, about listening to lectures on tide and not arguing the point when I bother to drive down to weymouth at my own expense to try and help them, but then it's not in a paid professional coach's interest to have anyone around with superior tactical advice is it? Then I always was naive..