Hi,

I drew a schooner rig on the Wantoo proa that I designed for the WoodenBoat Design Challenge III. You can find this on:
http://au.groups.yahoo.com/group/Woodenboatdesigncompetition/files/

The two mainsails are based on the same principles as windsurfing sails, with some adaptations. These sails can be sailed with acceptable light tension on the sheets. The booms (or wishbones) take care of the all vertical component of the forces. A slim sail does not have much of a horizontal component.
It is true that you have 4 sheets instead of 2 on an aero rig, however that is what makes it possible to steer the ship with the sails. You can't steer a horse with one bridle.

The masts are placed on the beams. My intuition says that this is the lightest and most efficient construction that is possible. The leeward hull does not need any reinforcements, except where it is connected to the beams. It will always be connected to the beams.

On a fast ship you will sail on high wind courses most of the time. Therefore efficiency when sailing high into the wind is the most interesting quality.
Conventional rigs are still based on the old way of sailing, with lots of weight underneath the waterline and a fixed hull speed that is slower than the waves and much slower than the wind.
It took hundreds of windsurfing sailmakers thousands of hours to get from the state of the art dinghy sail to the windsurfing rig as it is now. The balestron or aero rig type of sail was one of their many experiments.
I am sure multihull rigs and specially proa rigs still have a long way to go.
That is what makes them interesting to discuss.

In my opinion the aero rig is a sidestep in this development.
Maybe Rudolf is right when he says that even the whole concept of a jib is also a sidestep.
I agree that I have ever seen a bird or an airplane or anything that flies with a jib.
Carbon makes new solutions possible. Getting rid of stays and spreaders definitely makes sailing and rigging a lot simpler. The challenge is to get from the stiff idea of a conventional yacht rig to a flexible rig that responds well to all the changes in the wind and all the movements of the waves.

I am trying to develop self inflating sails to see what that concept can bring us.
I guess all multihull sailors share the same ideals: performance, light constructions, easy handling, simplicity.

Nol Twigt

--- In harryproa@yahoogroups.com.au, Rob Denney <harryproa@...> wrote:
>
> G'day,
> While I agree with some of what you say, I think it needs to be
> considered against the alternatives.  In particular, the crew in your
> video (very cool, exactly what Jan had in mind when we first discussed
> Blind Date) could easily handle the rig with a little instruction and
> no danger.  Put them on a conventionally rigged boat, (highly loaded
> sheets to release and then pull in, winches to tail and wind, changing
> sides/ends, getting in irons) and it would be a dangerous disaster.
> Other comments follow yours
>
> > The main thing is simply a matter of control. We have lots of shallow waters in the Netherlands. If you want to sail on the Waddenzee for example, you need to be able to sail with the rudders (almost) pulled up. This is impossible with an easy rig that is positioned in the middle of the leeward hull. End of story.
>
> The rig does not have to be sailed with both the jib and the main.
> Either can be lowered, under or over sheeted to move the balance point
> forward and back in tight situations.  If the main is not used, you
> will need a brace line to the front end of the boom, but this is not a
> big deal.
> >
> > - I do not like the way an easy rig looks. It does not look 'aerodynamically right'. Usually if things do not look fast they are not fast.
>
> That depends on who is doing the looking.  ;-)  The Wolfson Institue
> in Southampton did some tests comparing the ballestron rig with
> conventional sloop rigs.  The ballestron was very slightly slower
> upwind, faster on a reach (particularly a broad reach when the
> ballestron jib kept working, but the sloop genoa was not) and faster
> downwind until the sloop poled out their genoa.  These results were
> supported by real life tests by Yachting Monthly magazine on a couple
> of Hirondelle cats and Yachting World magazine on a couple of 34'/11m
> Sadler monos.  In both cases, the ease of use was a much more
> commented upon feature than the superior speed.
> >
> > - It looks kind of unnatural because it seems to be lifted from the ship. It is not one with the ship.
>
> That is due to the height of the boom.  I personally think that deck
> sweeping headsails and low mainsails, while aerodynamically superior
> (end plate effect) are extremely dangerous as they limit vision in the
> most likely sector from which another boat will appear.  However, if
> you can live with this, and the boom sweeping low over the deck during
> tacks, gybes and shunts, then lowering the boom will improve the
> aesthetics.
> >
> > - The look and feel is kind of lazy. Not interested, taking things too easy. Statical, almost dead.
>
> Very few cruisers would agree with this!  However, for those who like
> tweaking and hard work, it is easy to employ most of the trimming aids
> that a normal rig uses. For example: mast bend (controlled with the
> topping lift led to the boom end), mainsail twist (leech control line)
> and camber (downhaul/cunningham), foot curve (outhaul), jib twist
> (halyard and downhaul to adjust  location on the forestay), camber
> (sheet and backstay to control headstay sag).  We used all these while
> racing Rare Bird, but cruising we set and forget and let the bendy
> mast do the lion's share of the trimming work.
>
> > - The strongest forces are the vertical forces on the forestay and the leech of the mainsail. These enormous forces are countered by a boom that must be very strong and will be very heavy. This is not an elegant solution. It is brute force.
>
> True but much less brute force than mainsheet travellers, deck tracks
> for jibs, vangs and the beefing up, winches and multipart purchases
> they require.  It is also possible to make a much more elegant boom,
> but the prime requirement in the Vis was for low cost.
> >
>
> > - On the Blind Date the boom connected to the mast with a hinge. The result is that you can not trim the mainsail and the jib independently. You want much tension on the luff of the jib and little tension on the leech of the main. The topping lift could solve that problem, but that does not work on both bows. Two topping lifts would be better, but that would mean an extra line to take care of after every shunt. It would make it a little less easy rig.
>
> Correct, but still far less work than trimming a conventional rig,
> especially as bending the mast is only required in strong winds.  The
> hinge (boom free to pitch around the mast) is optional. The engineer
> made a good case for the pitching boom, but in retrospect I would not
> use it again. There is no reason why you cannot use wedges to lock it
> in position.
> >
> > - You can not sheet the mainsail and the jib independently. You can not steer the ship with the sails. You can not play with the waves and the sails.
>
> See above.  Plus the most important part of playing with the jib
> (altering shape and twist when sheets are eased) is done automatically
> as the rig rotates. It is far more efficient in waves to trim the
> entire rig with one lightly loaded sheet than it is to adjust two
> sails independantly
> >
> > - There are situations where you want to let go the mainsail without changing the jib. For instance when you are overpowered in a gust.
>
> Rotating/luffing the whole rig will always be more effective and more
> efficient than sailing under jib with the main flapping.
> >
> > In strong winds the mast has so much friction that it does not turn when the sheet is released. Not safe.
>
>  Definitely not safe!  The balance between the main and the jib on a
> ballestron needs to be in favour of the main at all times.
> >
> > The COE (Center of Effort) is behind the mast. This is necessary to get some power on the sheet and to make the rig turn when the sheet is released. The result is momentum 1 that makes the ship want to turn its nose into the wind.
> >
> > The mast is placed on the leeward hull. The COE is on the leeward side of the ship. The result is momentum 2 that makes the ship want to turn its nose into the wind.
> > Momentum 1 + momentum 2 make the ship by definition out of balance.
> > The balance can only be restored by using big strong rudders. The back rudder is used as a daggerboard.
> > This is again countering enormous forces with other brute forces: not elegant.
>
> All correct, but a lot more elegant, simple, safer, lighter and
> cheaper than a conventional rig with 2 rudders and two daggerboards,
> plus their cases.
> >
> > In shallow waters, when you need to pull the rudders up, the ship will be out of control. Momentum 1 + 2 are not countered anymore. The ship will turn it's nose into the wind.
>
> See above, plus the rudders can be built to be raised for shallow
> water and for balance. I almost always sail my Elementarry with the
> front rudder raised.
> >
> > Applied on the Visionarry proa's
> >
> > Visionarry looks modern, light, fast, like a flying saucer or a fighter plane, hi-tech. The aero rig looks old fashioned, slow, low-tech.
> > On a light ship that is built for speed, control is a crucial factor. The aero rig is static and does not contribute to the control of the ship. It needs extra control for it self.
>
> No more so than a conventional rig, but because the control is rarely
> needed, none of the boats so far have bothered to fit it.
>
> None of the above makes the easy rig perfect, but for short handed
> performance cruising, I have not come across a better rig. The only
> one that comes close is a schooner una rig, partly because it opens up
> the lee hull for accommodation and gives a lot more balance options,
> particularly while shunting. On the down side of the schooner is
> higher sheet loads (possibly reduced by raking the mast forward in
> it's bearings), poor upwind light air performance and more cost.
>
> The other thing that should be taken into account is the extreme
> (relatively speaking) light weight that is possible with a ballestron
> on a proa. This is partly as it is unstayed, but the weight of all
> the deck gear and strengthening required to utilise a conventional rig
> adds a lot of weight, complexity and cost. A 15m multi with all of
> Blind Dates space and attributes weighing 2 tonnes would not be
> possible with any other type of rig.
>
> There are a bunch of other rigs to try (wings, junks, crabclaw, kites,
> etc), but none of them match the easyrig, in my experience. The
> bigger the boat, the further ahead the easyrig gets.
>
> regards,
>
> rob
>