Subject: Re: [harryproa] Re: Bi-directional square rig
From: "Rick Willoughby rickwill@bigpond.net.au [harryproa]" <harryproa@yahoogroups.com.au>
Date: 3/2/2019, 5:16 PM
To: "harryproa@yahoogroups.com.au" <harryproa@yahoogroups.com.au>
Reply-to:
harryproa@yahoogroups.com.au

 

My untested solution to dumping sail was to sheet the lower corners of each sail panel with 2:1 purchase to the yard.  I was aiming to do that with a single winch at each end and bringing the individual sheets from the same end of the yards to a common sheet.  Both ends would need to be released to completely dump the sail drive and leave the panels to flog.  If you look at the Paul McKay Aerojunk he shows three control sheets.  With planned 5 panels I would have 10 sheets in total and there would be associated windage.  I would arrange the sheets to give the best sail shape for windward performance.  I never got so far as laying out the length of the sheets and the location of the winches to give the best shape through the range of sailing.  We did contemplate a model but never actually built it.


With the 18m proa I have found that just bearing away takes a lot of load off the sails.  On a boat that can achieve wind speed and easily get to 15kts, it is not hard to reduce sail  loads.  Of course that requires room.   Some of the experienced mono sailors who have been out on the proa are convinced the wind has died until the boat is bought back into the wind.  On the other hand rounding up in a gust will get the boat in irons and that is not particularly nice as the sails flog heavily the whole time it takes to get the rig loaded in the opposite direction to get sailing again.  

As previously noted, the concept of the square rig was explored as an alternative to the schooner rig as there was unacceptably high cost involved in converting from Aerorig to schooner.

Rick
On 3 Mar 2019, at 2:45 am, Mike Crawford mcrawf@nuomo.com [harryproa] <harryproa@yahoogroups.com.au> wrote:

I had almost committed to buying a used Drangonfly 920 that had been grounded, and putting in the time to repair it, when I came upon the harryproas.  I wouldn't have thought that all those features that contribute to weight and risk/failure could have been designed away, but rob did it, and I can never look at that huge stayed rotating mast the same way again.  Maybe there's a solution for the square rig, too.

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Posted by: Rick Willoughby <rickwill@bigpond.net.au>
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