Subject: Re: [harryproa] Re: extra sails for light airs |
From: Mike Crawford |
Date: 4/20/2009, 1:47 PM |
To: harryproa@yahoogroups.com.au |
Reply-to: harryproa@yahoogroups.com.au |
If I had to go with a screecher, I'd go with the scheme Arto
suggests, mounting the tack on the leeward bow and the clew on the
boom. That would still preserve some of the ability to dump wind with
just the mainsheet, and would allow the mainsheet to control the
screecher as well as the main. As some point out, a reverse-balanced
sail could cause confusion at the wrong moment.
I'd actually consider two staysail self-furling screechers with
continuous line furlers, so you can drop one and hoist the other,
without having the windage of permanent stays. It wold also make it
easy to keep a full-roach or squaretop main.
If shunting, you could probably leave both up the whole time, and
just furl/unfurl though the stay/head attachment wold need to be pretty
strong in order to resist any torsion generated by the changing angle
of the mast.
I might not go to the mast top, though. If the proa is already
around a Bruce of 1.8, the screecher is already overkill in some ways.
The lower stress on the mast due to a fractional rig might be nice.
This would have the added benefit of being able to sail in either
direction even if the mainsail blows out.
- Mike
Rudolf vd Brug wrote:
HiFor a screecher used in light winds it should not be a problem.The pull from the screecher would counteract the pull from the leech of the mainsail.That would result in the mast bending to leeward. As the mast is designed for the max righting moment of the boatthe extra sail should be no problem for the mast. However a headsail on an unstayed mast wil suffer from a sagging luffas wind increases. So it would have to be rolled up in time as it will loose shape fast when the wind gets up.regards,Rudolf----- Original Message -----From: Gardner PomperSent: Monday, April 20, 2009 3:08 PMSubject: Re: [harryproa] Re: extra sails for light airs
In order for a lazy cruiser to use the sail much, I expect that having
it furled on the fore boom would be much easier. It would have to be
rolled up for each shunt, but we had to roll ours up to tack on the
Maine Cat.
I had not thought of it unbalancing the rig, but it would seem that
could be remedied by just having a couple lines (one for each shunt
direction) attached to the end of the foreboom. These lines could be
stowed when not using the screacher. You would lose your
auto-depowering ability, but only when sailing in light air, and
letting go the screacher sheets should accomplish the same thing.
The part that I am unclear on is the effect on the mast of a large
masthead foresail. I imagine it would have to be much stiffer. Is that
a fatal problem?
- Gardner
On Mon, Apr 20, 2009 at 5:54 AM, Robert <cateran1949@yahoo.co. > wrote:uk
>
>
> -Makes a lot of sense for a mule. Is a stayless rig allowed to have a
> staysail? For a schooner I would think a screecher off a bridle between the
> bows. The bridle can be adjusted to bring the tack to ww for better downwind
> performance. Also an extra triangle sail for the aft mast tacked to the ww
> hull. Need all hands on deck when it comes to a shunt
>
> r -- In harryproa@yahoogroups.com.au , "Herb Desson" <squirebug@...> wrote:
>>
>> In the case of a schooner, I fancy a staysail and mule. This would
>> approximately double the sail area. The mule would be about 40% of working
>> sail area, the staysail about 60%.
>>
>> Best regards
>> Herb
>>
>>
>> --- In harryproa@yahoogroups.com.au , "Robert" <cateran1949@> wrote:
>> >
>> > What are the latest thoughts for extra sails for light air?
>> > My 2c
>> > -Big asymmetric hanging on a bridle between the two bows. This requires
>> > a bit of a hassle when shunting.
>> > _ Big symmetric attached to both lee bows with the ability to harden up
>> > either edge whichever becomes the luff. A bit like a flexible dyna rig.
>> > difficult to make such a sail but this is used in square riggers with some
>> > success. Todd's examples using a stiff sail gives some plausibility to this.
>> > If it worked, would be the easiest to shunt
>> > - Two screechers on roller reefing on each bow. Hard to keep enough
>> > tension on the forestay and extra windage when not needed and makes the mast
>> > need to work in a different way
>> > -Screecher or asymmetric on a prodder on the boom. Awkward to balance
>> > the rig
>> > -Hang a high lift kite between the mast top and the ww bow
>> > -have an extra track on the mast and have a 5-6m extension to get some
>> > of the extra wind up high. Not as much area as the other options
>> > -Go telescopic for an extra 60-80%. Complexity and getting sails that
>> > cover the possible differences in mast shapes
>> > -Simply have a taller mast and reef earlier. extra windage when not
>> > needed.
>> >
>>
>
>