New Posts New Posts RSS Feed: Debunking Dodgy Sailing Theories
  FAQ FAQ  Forum Search   Register Register  Login Login

Debunking Dodgy Sailing Theories

 Post Reply Post Reply Page  <1 56789>
Author
RS400atC View Drop Down
Really should get out more
Really should get out more


Joined: 04 Dec 08
Online Status: Offline
Posts: 2956
Post Options Post Options   Quote RS400atC Quote  Post ReplyReply Direct Link To This Post Posted: 10 Nov 11 at 8:54pm
We're avoiding the issue of saying how flat we mean by flat.
I haven't measured it, but I would guess I'm talking about 8% depth being about what seems to work, looking at the lowest batten on a 400 main. That's for a beat when not only is the crew sat to leeward, but the helm is sat forward and as leeward as possible.

Sometimes of course, you can avoid beating because light winds will 'always' shift, and it's better to be moving than pointing......
Back to Top
Chris 249 View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 10 May 04
Online Status: Offline
Posts: 2041
Post Options Post Options   Quote Chris 249 Quote  Post ReplyReply Direct Link To This Post Posted: 14 Nov 11 at 10:33am
"I begrudginly tried in in a drifter and it worked"

Ummm, a lot of people in some classes have tried the tight outhaul in drifters and found that it worked for them, too. And they are certainly not all skiffies; even in 1989 IOR 50s some America's Cup winners had the outhaul tight all the time.

Certainly it doesn't work in all craft and no one who has read the stuff I write would pretend that I feel that skiffs are any better than any other boat, but have you any evidence (ie skiff worlds victories as well as the 505 ones I presume you have) that you are right and they are wrong?

For what it's worth, I was surprised when I saw the tight-outhaul theory in action too, but the information I got was that generating more power from increasing camber in the lower part of the mainsail was not as effective as losing efficiency in that area in exchange for being able to sheet more tightly. Trying to sheet tightly with a deep mainsail foot just lead to a stalled slot (to use that term loosely).

Of course easing the outhaul works in most boats, but surely there is one hell of a jump from you finding that it didn't work in your boat, to saying that everyone who uses a tight outhaul in any class is getting it wrong? I know in one class I sail, the fast high-wind settings for camber in the top 1/3 of the sail is (at a guess) about 6%, in another it may be 5%, whereas in another class it's negative camber, with the top battens inverting.  

If upper camber can vary so much in a breeze depending on class, why not lower camber?


Edited by Chris 249 - 14 Nov 11 at 10:46am
Back to Top
JimC View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 17 May 04
Location: United Kingdom
Online Status: Offline
Posts: 6286
Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 14 Nov 11 at 10:47am
The trouble is because sails vary so much in design and shape, and because one thing affects another its difficult to be too dogmatic... You may find setting one aspect of the shape right according to theory sets another aspect comprehensively wrong and its just a question of seeking the best compromise.
Back to Top
furtive View Drop Down
Posting king
Posting king


Joined: 30 Mar 05
Online Status: Online
Posts: 186
Post Options Post Options   Quote furtive Quote  Post ReplyReply Direct Link To This Post Posted: 14 Nov 11 at 11:08am

And all this assumes that what works for one sailor/team will work for another. Just because one setting/sail shape/mode of sailing/etc. is (supposedly) theoretically faster, and indeed faster for a particular sailor, it doesn't necessarily mean that all the other sailors in that fleet, with their enormous ranges of skill, experience, technique, fitness, strength, weight, tactical awareness, etc, etc, will automatically go faster by aiming for (and quite possibly not achieving) the same set up. Or indeed that a completely different set up can be argued as being theoretically (and actually) faster.

Isn't that one of the sport's most attractive features? There are many many ways to skin the many cats involved.
Back to Top
Rupert View Drop Down
Really should get out more
Really should get out more


Joined: 11 Aug 04
Location: Whitefriars sc
Online Status: Offline
Posts: 8609
Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 14 Nov 11 at 11:16am
Who'd have thought one throwaway line would cause such upset...
 
I'm sure it works for many cuts of sail, but I've seen many boats going nowhere at all with outhaul bar tight having read in a book that it needs to be tight in a drifter. People actually need to question ALL the statements made in books and articles about what makes a boat go fast, and use them as a starting point. Sadly, many take what is written as gospel and follow it blindly.
Firefly 2324, Lightning 130, Puffin 229, Minisail 3446
Back to Top
dics View Drop Down
Far too distracted from work
Far too distracted from work


Joined: 05 Oct 05
Online Status: Offline
Posts: 317
Post Options Post Options   Quote dics Quote  Post ReplyReply Direct Link To This Post Posted: 14 Nov 11 at 1:27pm

Windward heel. How does it is work? Or is it a myth?

Back to Top
Contender443 View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 01 Oct 04
Location: United Kingdom
Online Status: Offline
Posts: 1206
Post Options Post Options   Quote Contender443 Quote  Post ReplyReply Direct Link To This Post Posted: 14 Nov 11 at 2:04pm
Originally posted by dics

Windward heel. How does it is work? Or is it a myth?

It works! Anyone who sails without a rudder knows how it works.
 
Next time you are out don't hike too hard and heel the boat to leeward and the boat will turn into the wind. Now ease the sheet and have some windward heel and the boat will now bear away.
 
So this is not a theory it is a fact.
Bonnie Lass Contender 1764
Back to Top
Rupert View Drop Down
Really should get out more
Really should get out more


Joined: 11 Aug 04
Location: Whitefriars sc
Online Status: Offline
Posts: 8609
Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 14 Nov 11 at 3:07pm
Originally posted by dics

Windward heel. How does it is work? Or is it a myth?

Do you mean sailing in straight lines heeled to windward, like Steve Cockeril advocates? Seems to work for him, but I think it takes a lot of practice to get right. Must experiment this winter, while there are fewer leaves on the tres rond the lake, so the winds are steadier.
Firefly 2324, Lightning 130, Puffin 229, Minisail 3446
Back to Top
dics View Drop Down
Far too distracted from work
Far too distracted from work


Joined: 05 Oct 05
Online Status: Offline
Posts: 317
Post Options Post Options   Quote dics Quote  Post ReplyReply Direct Link To This Post Posted: 14 Nov 11 at 3:47pm
Yep.
 Windward heel sailing upwind to the windward mark. I do it and I get get lifted up nicely. No-one else seems to do it at the club. Whenever I have been out with the Tasers they have shunned the idea prefering to keep the boat "flat" (in taser terms means 30 degrees to leeward it seems!!). So I thought why does it work? How do the foils give you the lift? How does the hull shape affect it? Also it seems half the people I talk to say it works and others say it does not (but they seem to be the people who can not do it).
Back to Top
Contender443 View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 01 Oct 04
Location: United Kingdom
Online Status: Offline
Posts: 1206
Post Options Post Options   Quote Contender443 Quote  Post ReplyReply Direct Link To This Post Posted: 14 Nov 11 at 4:48pm
I think we are talking more about balance here. What you think of as flat is usually a slight heel to leeward and windward heel to you is probably flat.
 
If your rudder is set up properly then a flat boat will give neutral helm and therefore no drag.
Bonnie Lass Contender 1764
Back to Top
 Post Reply Post Reply Page  <1 56789>

Forum Jump Forum Permissions View Drop Down

Bulletin Board Software by Web Wiz Forums® version 9.665y
Copyright ©2001-2010 Web Wiz
Change your personal settings, or read our privacy policy