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Foil lift / tracking

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pondmonkey View Drop Down
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    Posted: 14 Feb 13 at 6:16pm
I've done it before with other boats, notably the RS100 when the stars aligned once and against all odds I nuked a 300 to the windward mark once, but I found last Sunday that upwind when the boat just 'felt right', I seemed to go through a phase of pointing lower than others, but then started tracking to windward despite the angle I was pointing.

It was devastingly effectively at clawing back a 20 boat length gap after missing the start, I'd just like to know how to do that on demand, rather than rely on some celestial passing. Any ideas?
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tgruitt View Drop Down
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Post Options Post Options   Quote tgruitt Quote  Post ReplyReply Direct Link To This Post Posted: 14 Feb 13 at 6:18pm
Originally posted by pondmonkey

I've done it before with other boats, notably the RS100 when the stars aligned once and against all odds I nuked a 300 to the windward mark once, but I found last Sunday that upwind when the boat just 'felt right', I seemed to go through a phase of pointing lower than others, but then started tracking to windward despite the angle I was pointing.

It was devastingly effectively at clawing back a 20 boat length gap after missing the start, I'd just like to know how to do that on demand, rather than rely on some celestial passing. Any ideas?


I thought that is how you are supposed to point well? That's what I've always done, drive off hard and get the boat up to speed and will keep nice and high.
Needs to sail more...
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getafix View Drop Down
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Post Options Post Options   Quote getafix Quote  Post ReplyReply Direct Link To This Post Posted: 15 Feb 13 at 6:45am
A long time sailing friend and nemesis used to talk about 'making the foils work' ... it took me some time to work out what the heck was being referred to, but yes, if you focus you can do it and what really struck me was the wind range it works across, it's not just for when it's breezy

Edited by getafix - 15 Feb 13 at 6:46am
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Post Options Post Options   Quote Oatsandbeans Quote  Post ReplyReply Direct Link To This Post Posted: 15 Feb 13 at 7:26am
I am a little bit suspiciuos of some wonderful effect where the foils all of a sudden start to generate extra lift and dramatically improve the Vmg. I suspect that when incidences occur where the boat suddenly goes into warp speed and sails up and around the competition the effect probably lies in the sail setting. Sometimes sailors can get end up " parked-up" on the race course with their sails stalled and little forward speed, and sometimes as one does this the boats close by endup in the same state as they try to copy the angles and sheeting of the first boat. If you then come along with all your sails set correctly and good flow on the foils you can sail up to and around the poor bunch and off into the distance. 
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Post Options Post Options   Quote rb_stretch Quote  Post ReplyReply Direct Link To This Post Posted: 15 Feb 13 at 7:43am
The foil effect was even more exaggerated in windsurfers particularly in the period late 80s to mid 90s when fins were rarely above 35cm long. I reckon you probably needed well over 10knots of boat speed before you could even consider going upwind.
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Post Options Post Options   Quote maxibuddah Quote  Post ReplyReply Direct Link To This Post Posted: 15 Feb 13 at 7:47am
According the Cockerell bloke its to so with heeling slightly to windward while pointing about right and at a certain boat speed with a certain foil and Hull shape then the boat will track to windward. I did it once in a laser. Unfortunately I didn't realise that was what did it so didn't try again.

I believe the theory is more to do with the shape of the hull through the water but the foil is still important. When heeling to windward the centreline of the boat is the leeward edge baking contact with the water and is straight. The windward side is curved. This produces a flow similar to an aeroplane wing causing lift to the windward side. However it only seems to work with certain foil/Hull shape combinations.
Everything I say is my opinion, honest
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pondmonkey View Drop Down
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Post Options Post Options   Quote pondmonkey Quote  Post ReplyReply Direct Link To This Post Posted: 15 Feb 13 at 9:02am
Originally posted by rb_stretch

The foil effect was even more exaggerated in windsurfers particularly in the period late 80s to mid 90s when fins were rarely above 35cm long. I reckon you probably needed well over 10knots of boat speed before you could even consider going upwind.

I'm not sure this is the same, I've certainly carved upwind on the fin of windsurf boards many a time, but this felt totally different.  It was as if there was a tractor beam (albeit a very lame, but noticeable one) slowly drawing me to windward.... I'd love to know how to do it again.

It was relatively windy, no tide, slight reservoir chop but nothing to unsettle the boat.  I was relatively powered up and thought I had the boat flattish and nicely trimed fore/aft... upwind speed, in a Solo... hmm, no GPS, but guessing maybe 6 knots through the water??? 
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Post Options Post Options   Quote Daniel Holman Quote  Post ReplyReply Direct Link To This Post Posted: 15 Feb 13 at 9:21am
Originally posted by pondmonkey


... upwind speed, in a Solo... hmm, no GPS, but guessing maybe 6 knots through the water??? 


Ha ha ha ha ha 6 knots upwind in a solo!!! Thats the best laugh I've had in a long time! You'll win every race at the worlds by 3 minutes!
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pondmonkey View Drop Down
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Post Options Post Options   Quote pondmonkey Quote  Post ReplyReply Direct Link To This Post Posted: 15 Feb 13 at 10:02am
Originally posted by Daniel Holman

Originally posted by pondmonkey


... upwind speed, in a Solo... hmm, no GPS, but guessing maybe 6 knots through the water??? 


Ha ha ha ha ha 6 knots upwind in a solo!!! Thats the best laugh I've had in a long time! You'll win every race at the worlds by 3 minutes!

right... I'm off the Bristol channel on a spring ebb armed with my heinously out of class GPS device.... I will spike 6 knots and prove you wrong one day Holman!
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Post Options Post Options   Quote G.R.F. Quote  Post ReplyReply Direct Link To This Post Posted: 15 Feb 13 at 10:19am
I bet it did more than 6 knots upwind on that back of that low loader, where you should have left it... LOL
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