It looks though, Arto, that when a strong wind gets inside of the double sided pocket in a way not intended, the whole wing gets destroyed pretty fast. That would be a worry for a cruiser. Luc
--- In harryproa@yahoogroups.com.au, Arto Hakkarainen <ahakkara@...> wrote:
>
> Low aspect rigs are good downwind. They don't have as good L/D ratio as high aspect and so cannot be as good upwind as high aspect ratio sails.
>
> Mike: take a look at matinbleu.over-blog.com to see one good version of the swing rig. The more I think about it the more I like it. Matin Bleu also has two identical sails arranged as schooner and claim to be very happy after sailing around the world with it.
>
> Arto
>
>
> ________________________________
> From: Mike Crawford <mcrawf@...>
> To: harryproa@yahoogroups.com.au
> Sent: Monday, October 24, 2011 5:41 PM
> Subject: [harryproa] Re: wrong sails
>
>
>
> Ian,
>
> <<lug rigs were used for thousands of years we know they work,they became unpopular because you had to change them round not so on a Proa>>
>
> I can see how a dipping lug could be very efficient -- smooth airflow, nice amount of sail area up high in the wind, no boom or mast to spoil shape or create turbulence, and so forth. I'm a fan of loose-footed or semi-loose footed gaff rigs, such as the Wharram wing sail ( http://www.wharram.com/site/sites/default/files/imagecache/product_full/wingsailconversion_1.jpg ) and the Norseboat gaff rig ( http://www.norseboat.com/NorseBoats_files/norse4.jpg ) for many of the same reasons.
>
> However, I don't see how the proa would eliminate the need to change sides on a dippiing lug, and I don't see how a lug with a boom would be efficient in both directions.
>
> Could you explain?
>
> <<therefor D shaped easy to handle and lots of power>>
>
> Agreed. Another thing I like about the gaff rigs -- if the sail is cut properly, you can get great shape in very light airs without having to manhandle a batten switch from one side to another. I loved that about my Norseboat until I sold it (I live on a north/south inlet, and the mast just wasn't tall enough to sail in light east/west winds).
>
> <<ratio of 3 to 1>>
>
> While that short/wide ratio worked well for crewed ships, it might be a challenge when singlehanding a fast multihull. Switching a sail like that, as with the very efficient crab's claw (at least on a reach), could be difficult to do by one's self once the wind picks up. You'd either need to: a) dip the sail to switch sides, or b) temporarily put the full sail area perpendicular to the wind as the sail switches sides during a shunt.
>
> <<The sails should be>>
>
> Geat link! I've seen pha, and we've discussed it on this forum before, but I wasn't aware of this document. Thanks.
>
> I'm even more a fan of the swing-wing junk rig than the gaff rigs, though I'm still on the fence about it with a proa. I see how it would work very nicely with a single mast, but if I go with a schooner rig in order to get more sail area while fitting under bridges, the swing-wing might get more complex. It would likely require either rotating masts, or at least rotating booms, in order to allow two sails in line to work in tandem.
>
> That said, I'm confused as to how the lugger would deliver the shape of a swing-wing in both directions without the problems mentioned above for the 3:1 ratio low rig.
>
> So, while I don't yet get the lug rig, I guess you could say that I'm again sold on the swing-wing concept. I'm happy to learn more, though. I was highly skeptical of the swing-wing at first, but then discussion, particularly Rudolph's input, convinced me I'd been too hasty in my judgment.
>
> - Mike
