i think both of you are neglecting the huge performance value of the slot between the jib and main. the accelerated flow from the jib onto the back of the main is a HUGE benefit. 1+1=3. it's like a third sail.
i'm not completely familiar with all the boats out there, but are their any open development classes with no restriction on sail area for which a una rig is preferred to a bermudan? my impression is no. i infer that the reason is because for a given righting moment the most efficient sail plan is a bermudan rig. i've read that A-cats only have unas b/c of a restriction on total area. am i wrong on this?
that being said i'm on the fence about una vs. balestron for a proa. the saggy jib really bothers me. one fix is to get a high-modulus sail and crank on the outhaul. hobie cats and farrier tris both have rotating masts and hence loose stays and tension the forestay with LOTS of mainsheet. should work on a harryproa too i think.
but then the mast would have to be heavier because of the compression. and you've got the weight of the fore boom as well. i really don't know where the optimum lies here. and then there's the rudder issue!!
wetas have no boom or traveller and sail down wind just fine without. has anyone considered skipping it on a una rigged proa as well? could purposely go aback to drop it on the nets when taking it down...
ben
--- In harryproa@yahoogroups.com.au, Mike Crawford <mcrawf@...> wrote:
> Personally, I wouldn't say that the lee helm with one rudder is a mark
> against the easyrig. If you put an una rig on a proa that has a
> tendency to luff into the wind, the additional weather helm would make
> it luff more. Neither rig is perfect.
>
> In the end, it's a matter of preference.
>
> The una rig will have a higher aspect ratio and taller mast than an
> easyrig with the same sail area. However, it will also have higher
> sheet loads, and jibes will take some skill. You also get the option of
> sailing with a single foil, at least on the smaller proas. If you want
> to race, don't mind the higher sheet loads, and prefer to have the mast
> waaay up there (more sail where it counts when there's no wind), it's
> perfect.
>
> If you want to cruise, there's a lot to be said for the lower sheet
> loads and graceful jibes of a semi-balanced rig. You'll also have a
> lower bare pole if the wind really starts to howl and you can't get out
> of the way, and the center of effort will also be lower. As for the jib
> tension, it's not perfect, but that's not the end of the world. Cut the
> jib for the right shape with a certain amount of sag in the stay and it
> will still be efficient.
>
> If you want to both cruise and race, it's a toss-up. That tall una
> will be faster, but require more effort. How lazy are you? I'm
> personally pretty lazy 75% of the time that I'm sailing, so that colors
> my rig preferences.
--- In harryproa@yahoogroups.com.au, Rob Denney <harryproa@...> wrote:
> My thinking exactly. Hope to get round the shortcomings by telescoping
> the rig and raking the mast forward so the centre of rotation is just
> ahead of the coe, same as the ballestron. Gybes aren't (or shouldn't be) a
> problem on a harry.
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