what''s up with sail twist? - Page 2 - SailNet Community
Reply
 
LinkBack Thread Tools
post #11 of 16 Old 04-01-2004
Moderator
 
Jeff_H's Avatar
 
Join Date: Feb 2000
Location: Annapolis, Md
Posts: 7,146
Thanks: 6
Thanked 190 Times in 155 Posts
Rep Power: 10
     
what''''s up with sail twist?

I diagree with the point about needing more twist in waves. More twist in wave and wind means more heeling, and less drive and speed. Trimming the whole sail for an average setting setting (even if that means less twist) means that you have the whole sail working optimally more of the time even if the sail suffers small stalling and low angle of attacks at the end of each swing.

Jeff
Jeff_H is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #12 of 16 Old 04-01-2004
Junior Member
 
Join Date: Feb 2004
Posts: 25
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
what''''s up with sail twist?

Jeff -- I''m interested in your comment about not wanting more twist in waves, since it runs directly counter to the conventional wisdom (e.g., Dobbs Davis''s article right here on Sailnet, or Stewart Walker, or Peter Isler / Vince Brun to pick on a few.)

But oftentimes people who defy the conventional wisdom, especially people like you who are clearly coming from a position of solid theoretical and practical knowledge, are onto something interesting. Care to elaborate?
ccboston is offline  
Quote Quick Reply Share with Facebook
post #13 of 16 Old 04-02-2004
Moderator
 
Jeff_H's Avatar
 
Join Date: Feb 2000
Location: Annapolis, Md
Posts: 7,146
Thanks: 6
Thanked 190 Times in 155 Posts
Rep Power: 10
     
what''''s up with sail twist?

Well, even people like myself can learn something from the likes of Isler, Walker and Brun. I have generally followed the approach of setting the sail for optimum drive at an average position and carried minimal twist (but quite powered up) in a chop. It has generally been quite successful and came to the conclusion that it was faster in one-design keel boat racing where I could check it against competition and the sails, but given the sources, I guess I may need to experiement with carrying more twist in a chop.

The only other thing is that most of my current sailing and racing is in petty large boats (J-22''s, Cat 27''s, J-105''s, Farr 11.6 and a 40.7) and perhaps twist works better in smaller boats. I''ll just have to give it a try next time that I am in a chop and need to open up on a competitor. Thanks for the input.

Jeff
Jeff_H is offline  
Quote Quick Reply Share with Facebook
post #14 of 16 Old 04-02-2004
Junior Member
 
Join Date: Feb 2004
Posts: 25
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
what''''s up with sail twist?

I dunno -- I''m not much of a sailing expert -- I''ve spent more time in the library than on the racecourse... But I do know something about the development of technical ideas in science and engineering, and I know that often times ideas are really faddish. The "conventional wisdom" becomes accepted simply by repetition... The experts all start quoting each other, and pretty soon everyone starts accepting something (like "more twist in waves") as gospel truth without actually going out and doing the hard work of experimenting.

That''s why I got interested in your contrrarian position, especially given your willingness to experiment for yourself.
ccboston is offline  
Quote Quick Reply Share with Facebook
post #15 of 16 Old 04-02-2004
Senior Member
 
RichH's Avatar
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 3,796
Thanks: 27
Thanked 192 Times in 181 Posts
Rep Power: 17
   
what''''s up with sail twist?

Your statement of ''conventional wisdom....." is profound!
Hint: Compare the ''twist'' on such things as turbine blades and propellers to the ''twist'' on sails. You''ll find that for regimes of greater ''tip speed'' you''ll find correspondingly less ''twist''; the ''conventional wisdom'' here avoiding that the greater the velocity over a foil/wing requires LESS angle of attack and less camber, etc. Just an aerodynamic fact. You dont ever want to disagree with the conventional ''experts''. But then again the same arguements will apply to ''slot effect'' vs. ''conventional wisdom'' ;-)
RichH is offline  
Quote Quick Reply Share with Facebook
post #16 of 16 Old 09-08-2004 Thread Starter
Junior Member
 
Join Date: Oct 2003
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
what''''s up with sail twist?

hey, this is a lot of fascinating information about sail twist which i look forward to studying the next time i''m at work.
hrae is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Proper use of the Traveler PDixon Boat Review and Purchase Forum 34 04-23-2014 04:00 PM
Windward performance deseely General Discussion (sailing related) 21 04-01-2012 02:42 PM
Sloop, Cutter or Ketch jsgsail Boat Review and Purchase Forum 17 12-26-2008 02:47 PM
Traveler usage? Humpwalker Seamanship & Navigation 22 02-17-2007 10:54 AM
sail profile bazcarr General Discussion (sailing related) 3 12-14-2001 03:17 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome