Subject: Re: Predicting performance?
From: Mike Crawford
Date: 6/1/2010, 10:27 AM
To: Gardner Pomper

Gardner,

  Experimenting on the plywood platform makes a *lot* of sense. 

  You'll be able to try all sorts of quick-and-dirty variations at a small scale, and for a low cost, in a real sailing environment.  I appreciate the work that Todd has done with his models, but sailing a real boat in high winds, when it's your butt on the line, is a different experience than sailing a model.

  Your "canting" design would help with one of my two major objections of the dynarig: the inability to leave the sails depowered without tending to them.  If you could actually luff the sail, and then ignore it for a minute or two at a time, the rig would be a lot safer than a standard dynarig.  Unless, of course, you could replicate the rig of the Maltese Falcon and simply press a button to furl all the sails. 

  Sometimes you just need to drink, pee, get a snack, put on a jacket, or check a chart, or reef, when the wind is up.  Unless you're sailing with a tiny amount of sail area, a sail that stays depowered is important for singlehanding.

  The cant could even be helped with a control line and some blocks inside the battens.  Tug on one side, the sail moves, and the cant is forced, regardless of what the wind is doing.  Tug on the other side and you're set for the other tack.

  I'll be particularly interested in hearing how the system works when you shunt in bigger winds. 

---

  Any comments on the Elan?  I'm curious as to how you enjoyed it and why you moved on.  I won't be getting one, but I do like the boat.

        - Mike

 

On 5/31/2010 12:48 PM, Gardner Pomper wrote:
(also off group)

Mike,

If I am going to experiment with this, it will be on the plywood proa I am slapping together with windsurfer masts and sails. It is not something I am going to be doing with a sailmaker. I would be interested in trying out both this rig, and a Dynarig, modified so that the "battens" actually encompass the mast, and have a central slot so that the air pressure of the wind cants the sail fore and aft. If that works, and doesn't kill performance, it would let it luff into the wind when released and I would only have to worry about the broadside on sailing, which Todd's models seemed to indicate was not a real issue.

Hope that explanation is clear. I know a picture would help. Think of it like the asymmetrical rudders I drew recently, with the pivot point at the top of the mast, and the sail cants back away from the wind.

- Gardner