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Pointing-so whats that all about?

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JimC View Drop Down
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 22 Dec 17 at 9:07pm
the Minisail doesn't have the best rig, foils or hull shape for pointing high.

Edited by JimC - 22 Dec 17 at 9:08pm
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Rupert View Drop Down
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 22 Dec 17 at 9:30pm
Get some speed up, get the chine in the water and you can get the boat pointing if you need to. Generally better to crack off a few degrees for speed, though. A decent sail set well helps a lot.
Mind, a lot of "pointing high" is actually spotting the lifts.
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423zero View Drop Down
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Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 22 Dec 17 at 9:36pm
Will the Laser like battened sail fitted to my Sprint allow it to point higher than the simple Topper style triangular sail ?
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 22 Dec 17 at 10:10pm
The Mini sail is under foiled, needs a bigger centre board. It goes sideways if you try to point too hard.
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 22 Dec 17 at 10:20pm
That's where digging the chine in helps, but yes, they go better with a bigger board.

The sail won't make it point higher, but the greater power will mean you can pinch at times and maybe bleed the speed more slowly. Generally, keep the boat moving. Off the start line, ensure you have space to leeward. If you pinch when going slow, you will simply go sideways, and the low rig will be stuffed in dirty air. Make sure you can tack off and tack back into a clear lane, then build speed before you point higher.
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A2Z View Drop Down
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Post Options Post Options   Quote A2Z Quote  Post ReplyReply Direct Link To This Post Posted: 23 Dec 17 at 10:18am
It's worth splitting leeway from pointing.  Pointing angle is heading relative to true wind and leeway is the angle between heading and course.   Bigger boards reduce leeway, but don't improve pointing angle.   
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 23 Dec 17 at 10:41am
Originally posted by A2Z

It's worth splitting leeway from pointing.  Pointing angle is heading relative to true wind and leeway is the angle between heading and course.   Bigger boards reduce leeway, but don't improve pointing angle.   


I'm not convinced that's really a desirable split.

What we call leeway is simply the angle of attack the board must operate at in order to create enough lift to balance the sails. If a board is very undersize or badly shaped it may have to operate at a significant angle of attack to create enough lift, and that's going to be especially true of any foil that doesn't maintain good flow on the windward side, but its more about lift than anything else.

Once you have a board that's operating with decent attached flow both sides then extra area won't make much observable difference in a straight line at normal speed. Board size is really much more a differentiator when coming out of a tack when the board has to operate at very low speed with a lot of side load.
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Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 23 Dec 17 at 10:47am
Regarding Centreboard size, is it length or breadth ? Or is it in relation to size of sail ?
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 23 Dec 17 at 11:06am
Originally posted by 423zero

Regarding Centreboard size, is it length or breadth ? Or is it in relation to size of sail ?

All and none.
The centreboard has to provide enough lift to balance the forces coming from the sail. Bigger sail, more force. A long thin centreboard can do that, so can a short fat one. The long thin one will do it with less drag, but will be less tolerant of being given too much work to do, at which point it will stall out. The short fat one has more drag, but will continue to create lift (with ever more horrendous drag) at angles where a long thin one will simply give up.so a compromise must be made, and the best compromise will be different for different boats.
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Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 23 Dec 17 at 11:57am
This is centreboard fitted to Sprint (long and thin ?) approx 38" long by 14" wide at widest point. Appears looking at depth of hull and sail size to be adequate, not noticed much leeway, probably need someone following to have a proper look.

https://photos.google.com/photo/AF1QipNk9rVDCqP_NCaoebt0cBIcRnrYDO4GT6AUNsyT
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