On my Ericson built boat I've induced prebend by blocking the mast all the way forward at the partners. We sail with check stay tension going to weather except in very light winds when we want sag in the headstay. I typically sail with a very full cut but adjustible North main. With the combination of backstay, checkstay, halyards, vang and outhaul I can make the main into virtually anything I want. In big breeze to weather we pull the back stay down about 5 inches and then crank on a fair amount of checkstay--just enough to keep the main from inverting--which keeps the headstay nice and straight. At that point the top batten (which is full, as is the upper mid) is board flat.
I wish I could say that all of my sail adjustments insured great performance and lots of trophies, but I'm not that good.
Bob
The question of when and how much checkstay to use was a matter of some confusion to me when I first got the boat, but since my understanding is that optimal mast shape depends entirely on the cut of the main, I've learned over time what it takes to adjust the mast bend to optimize main shape. If the main is cut so that induced mast bend in the upper sections of the mast effectively flatten the sail, then there's no need for the lower mast sections to bend forward, which means sufficient checkstay pressure needs to be applied to keep the mid and lower sections of the mast in column. If the main is cut (or has aged) to require bending in the mid sections as well, then the checkstays need to be eased off until the main is boarded out - with an attendant decrease in headstay tension and less control over mast pumping, it seems to me. I would think that any new main would be cut so that mast bending in the upper sections only would be sufficient to board out the main.
Any comments?
Derek Reijnen
The Reijnen Company
phone: 206-842-4409
email: derek@reijnenco.com
-----Original Message-----
From: Richard Canning [mailto:rcanning@dimeo.com]
Sent: Thursday, July 15, 2004 2:06 PM
To: olson911@SailPix. com
Subject: RE: Checkstays
Guys,
Len asked a great question. Here is my response.
Rich
-----Original Message-----
From: Len Kremer [mailto:lkremer@barr.com]
Sent: Thursday, July 15, 2004 4:45 PM
To: rcanning@dimeo.com
Subject: Checkstays
Rich-Please send me copies of Ed's pictures that you discussed. How much of a diference in sailing performance were you able to see with the checkstays? What was the upper range of the wind speed that you used them? Thanks!
Len Kremer- Owner, Capo 30
Len,
Here is that email with the photos. We typically stopped using them when we were in blade conditions because you want the main flattened out. We would put hand tight tension on with the blade up to stop the mast from pumping.
Rich Canning
Received on Thu Jul 15 16:28:39 2004