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Why is this fast?

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    Posted: 04 Sep 06 at 10:23am

I guess it must be but I don't undetand why it is fast to have the mast so far forwards - I would have thought 90 degrees to the wind on the run would be best for maximum projected area ...



Edited by Guest#260
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Post Options Post Options   Quote BBSCFaithfull Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 06 at 10:31am
It moves the centre of effort towards the water etc etc. 
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Post Options Post Options   Quote Guest Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 06 at 10:35am

Originally posted by BBSCFaithfull

It moves the centre of effort towards the water etc etc. 

What?

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Post Options Post Options   Quote blaze720 Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 06 at 11:20am
Wind speed is (usually) progressively stronger above the waters surface and could be less turbulent as well.   Sailing in this manner therefore projects more of the sail area higher up into 'better' wind.  It also balances the rig about the centreline in a way a symetrical spinni would do in many other classes. Perhaps a Star pundit can comment on whether the hull produces less drag when digging in the windward chine.  Possibly a combination of all three (and other) factors.  Other non spinni classes do it as well without a keel .... OK, Finn, Laser spring to mind and even the Blaze can benefit offwind in lighter stuff sailing by the lee, going deep and with the rig over your head canted at an angle !    

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Post Options Post Options   Quote Stefan Lloyd Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 06 at 11:27am

Blaze720, I think you are misunderstanding the question, which was: why is the rig raked forwards downwind. You are talking about heeling to weather.

http://www.sailinganarchy.com/forums/index.php?showtopic=404 99 is talking about this subject at present. Quite a few keelboat classes do it. So do Merlins, although not to the degree Stars do.

 

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Post Options Post Options   Quote Stefan Lloyd Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 06 at 11:49am

Originally posted by turnturtle

Shrouds conventionally prevent the boom from extending a full 90deg to the mast downwind

Only on rigs with swept-back spreaders, which applies to all stayed dinghies I can think of and a lot of keelboats but not, I believe, Stars. Some keelboats, such as Stars, have in-line speaders in order that the boom can go out to 90 degrees and rely on the runners to stop the mast toppling forwards. 

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Post Options Post Options   Quote Guest Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 06 at 11:49am
Originally posted by Stefan Lloyd

Blaze720, I think you are misunderstanding the question, which was: why is the rig raked forwards downwind. You are talking about heeling to weather.

http://www.sailinganarchy.com/forums/index.php?showtopic=404 99 is talking about this subject at present. Quite a few keelboat classes do it. So do Merlins, although not to the degree Stars do.

 

Quite - why rake forwards to such a large degree?

There is no kite here so what is going on?

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Post Options Post Options   Quote Stefan Lloyd Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 06 at 11:58am
Rick, I'd suggest reading the thread I referenced. One theory is that is develops a flow over the main. I don't claim to know the real answer, but given the competitiveness of the class, if they do it, I bet it is quick.
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Post Options Post Options   Quote Guest Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 06 at 12:32pm

Originally posted by Stefan Lloyd

Rick, I'd suggest reading the thread I referenced. One theory is that is develops a flow over the main. I don't claim to know the real answer, but given the competitiveness of the class, if they do it, I bet it is quick.

No doubt it is fast as all the Star guys do it - I was just wondering if this translated to other classes - e.g. Taser or N12.

I read the SA thread thanks. Some interesting points.

Seems there is two things going on;

1) Raking the mast well forwards

2) Raising the jib

Rick

 

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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 04 Sep 06 at 12:39pm
Originally posted by turnturtle

surely it would be faster...


I think we can be pretty confident that sailors of the Olympic coffin have a very good idea about what it takes to make the bizarre rig on that bizarre boat go what passes for fast. I have less confidence that such concepts would be transferrable to higher performance boats...

Originally posted by Guest#260

I was just wondering if this translated to other classes - e.g. Taser or N12.


They're planing boats, not vintage leadmines, so probably not. Also bear in mind the frequency with which Star rigs go over the front...

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