Subject: Re: [harryproa] Re:: Downwind sails
From: "=?UTF-8?B?QmrDtnJu?= bjornmail@gmail.com [harryproa]" <harryproa@yahoogroups.com.au>
Date: 10/27/2015, 2:48 PM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

 

The kite idea is interesting. But it seems hard to control shorthanded.

About the gennaker, it is always in use on the M32 downwind. Even when fully reefed on the main. I guess the helmsman decrease power by steering more down if the wind is strong. Also, the M32 has curved foils, which probably helps downwind in strong winds.

Since the proa can't gybe, it's going to be slower than a cat downwind. My thinking with the downwind sail is that the proa could compensate for this by sailing faster and/or lower.

About the mast, I was thinking that since the gennaker is pulling in the top, it would maybe cause more stresses than if the forces would be evenly distributed.

On Tue, Oct 27, 2015 at 6:30 PM, taladorwood@yahoo.com.au [harryproa] <harryproa@yahoogroups.com.au> wrote:
 

I think the direction Rob is going is to an actual kite. As long as there is enough wind to fly it it can be more efficient than a gennaker.


For very light and variable winds there is no substitute for sail area. . .  and less wetted surface area.

I don't think a Harryproa design is the best design for light winds, a pure displacement hull (least low speed resistance) and a huge sail area are going to be better, since all of the speeds and forces are going to be lower.

About the mast strength, any mast is strong enough in light winds ^^  when a gennaker is most useful. The real question is at what airspeed does a gennaker have to come down? 15 knots?  The forces start rising rapidly above 15 knots.

15 knots is when sailing and kite flying start to get fun.

Talador


__._,_.___

Posted by: =?UTF-8?B?QmrDtnJu?= <bjornmail@gmail.com>
Reply via web post Reply to sender Reply to group Start a new topic Messages in this topic (4)

.

__,_._,___