mast rake and weather helm

Submitted by sail4w on Mon, 10/21/2013 - 00:23
Forums: 
Owning, Rigging, and Sailing the Flying Scot

  I've heard different things about mast rake aft.  Doesn't raking the mast aft (eg with forestay extender) decrease your weather helm?  Does tightening the shrouds (shortening them) also decrease weather helm?  I have  snug rig cut sails and seem to have more forward rake on the mast than I want. 28'7'' with no forward tension on the mast.  My shrouds also have more than 6" play and I seem to have more weather helm than I would like going to windward, all things being adjusted with sails, crew weight and position and main eased some if need,etc., to decrease weather helm.  Would shortening my shrouds take care of all of this and get better rake aft and more shroud tension? I appreciate any insights and experiences.

glennw_fs

Mon, 10/21/2013 - 09:07

For the snug rig, according to the tuning guide, you should be at 28'4-5" with a forestay tension of about 90 lbs.  You achieve this by adjusting the forestay tang turnbuckle and changing the position of the chainplate shroud attachment.
You should not need to actually shorten the shouds but you may need to add a forestay extension.

msman64

Mon, 10/21/2013 - 13:10

I second the advice from Glenn, it may take a few iterations but get the rake and tension as close to the guide as possible and then mark the settings with a sharpie.  You shouldn’t have to readjust very often, just check the rake each time you set up the rig.  Also, when you experience weather helm going up wind try pulling up the centerboard a bit (a few inches at a time).  This does not actually raise the board but shifts it aft changing balance of the boat in favor of less helm.
Mike Mandell
FS #5010
 

sail4w's picture

sail4w

Thu, 10/24/2013 - 13:06

thanks,Glenn
The one question I have pertaining to that is what is the sequence in setting up your boat which you follow to arrive at the proper rake distance(mast head to mid stern edge of deck eg. 28'4'') and getting the other numbers?  Is this the  distance  you have with the mast pushed back with little tension initially on the forestay and the shrouds where you think they should be set in their fittings?  When do you adjust the forestay tension with the toggle and/or an extension adjuster plate which I have, and when are the shrouds with their fittings adjusted in this process?  I know that I'm supposed to have about 1-1.5" of mast play fore and aft with a snug rig with that amount of rake 28'4-5.5" and about 6" of shroud play.  What kind of tension guage do you use to measure the forestay tension.  I've heard one doesn't use the Loos guages.  Thanks again.