Why does a gennaker/kite lift the bow?

   As simple as the subject above; but still I cannot get the answer. Anyone can help?
I mean, I know (or at least I think I know)  that a kite is a highly tapered and swept wing,  with more and more taper as you go upwards to the head of the sail. But then, again, what does it has to do with upward lift?

Thanks in advance for the answers; I know that once I get it, I'll be at least a couple of knots faster around the course  

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17mika Send Private Message Find Member's Posts Groupie Joined: 03 Nov 06 Location: Italy Online Status: Offline Posts: 52	Post Options Post Reply Quote 17mika Report Post Quote Reply Topic: Why does a gennaker/kite lift the bow? Posted: 12 Mar 12 at 5:49pm
	As simple as the subject above; but still I cannot get the answer. Anyone can help? I mean, I know (or at least I think I know) that a kite is a highly tapered and swept wing, with more and more taper as you go upwards to the head of the sail. But then, again, what does it has to do with upward lift? Thanks in advance for the answers; I know that once I get it, I'll be at least a couple of knots faster around the course

Lukepiewalker Send Private Message Find Member's Posts Really should get out more Joined: 24 May 06 Location: United Kingdom Online Status: Offline Posts: 1336	Post Options Post Reply Quote Lukepiewalker Report Post Quote Reply Posted: 12 Mar 12 at 5:56pm
	Run away! Run away! Before JimC gets here... Or, to put it another way, it doesn't.
	Ex-Finn GBR533 "Pie Hard" Ex-National 12 3253 "Seawitch" Ex-National 12 2961 "Curved Air" Ex-Mirror 59096 "Voodoo Chile"

winging it Send Private Message Find Member's Posts Really should get out more Joined: 22 Mar 07 Online Status: Offline Posts: 3958	Post Options Post Reply Quote winging it Report Post Quote Reply Posted: 12 Mar 12 at 6:01pm
	oh god, I'm getting my coat....
	the same, but different...

2547 Send Private Message Find Member's Posts Really should get out more Joined: 11 Aug 11 Online Status: Offline Posts: 1130	Post Options Post Reply Quote 2547 Report Post Quote Reply Posted: 12 Mar 12 at 6:01pm
	Of course it lifts the bow ...

JohnW Send Private Message Find Member's Posts Really should get out more Joined: 17 Jul 07 Location: United Kingdom Online Status: Offline Posts: 552	Post Options Post Reply Quote JohnW Report Post Quote Reply Posted: 12 Mar 12 at 6:04pm
	All the photos of 12 foot skiffs prove it!!

winging it Send Private Message Find Member's Posts Really should get out more Joined: 22 Mar 07 Online Status: Offline Posts: 3958	Post Options Post Reply Quote winging it Report Post Quote Reply Posted: 12 Mar 12 at 6:22pm
	nah, it's because they all stand at the end of the boat....
	the same, but different...

x1testpilot Send Private Message Find Member's Posts Visit Member's Homepage Posting king Joined: 11 Feb 11 Location: Ealing Online Status: Offline Posts: 175	Post Options Post Reply Quote x1testpilot Report Post Quote Reply Posted: 12 Mar 12 at 6:34pm
	It's the angle of the sail to the boat/wind/water. The force on the sail is perpendicular to the sail. think of a wooden board held in the wind, if you hold it to the top (leading edge) is into the wind and the bottom at 45 degrees to the leading, you will feel lift (also a real kite). The leverage of a long spin pole will make the effect more pronounced. Having said that the effect can't be that significant as 14's skiffs etc do tend to stand at the back of the boat + the wind is pushing the main forward too. I expect a better explanation will be forthcoming!
	I like to take pictures of sailing, but I'd rather be sailing! LCSC.org.uk Xdinghies.com/ X0 & X1

JimC Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6358	Post Options Post Reply Quote JimC Report Post Quote Reply Posted: 12 Mar 12 at 6:57pm
	It doesn't. There may be a lifting effect on the boat as a whole, but the bow is always pushed down. http://www.devboats.co.uk/cherubweb/liftbow.htm If it did you would see trapeze crews going for the front of the boat to get the weight forward when a gust hits. Edited by JimC - 12 Mar 12 at 6:58pm

RS400atC Send Private Message Find Member's Posts Really should get out more Joined: 04 Dec 08 Online Status: Offline Posts: 2957	Post Options Post Reply Quote RS400atC Report Post Quote Reply Posted: 12 Mar 12 at 7:12pm
	I think Jim's argument is a little spurious, because in most of the bow up pictures, the crew are back but the upward force of the water is also concentrated aft. The sum of the vectors of the 3 strings on a kite pulls in a certain line. Whether that is pulling the bow up or down depends also on where the reaction force (drag on the hull etc) is ahead or astern of that line.

Rupert Send Private Message Find Member's Posts Really should get out more Joined: 11 Aug 04 Location: Whitefriars sc Online Status: Offline Posts: 8762	Post Options Post Reply Quote Rupert Report Post Quote Reply Posted: 12 Mar 12 at 7:15pm
	There are many tales of boats going down the mine less once the kite is up, but this doesn't mean it gives lift. What does happen is beyond me, though - probebly to do with centres of effort or something.
	Firefly 2324, Lightning 130, Puffin 229, Minisail 3446