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.
- Mike
bjarthur123 wrote:
another nail in the coffin of the balestron, huh? first crappy jib luff tension, and now needing both rudders down for helm balance.
so the idea is that... there is less total drag with a single high-aspect foil than there is with two foils that provide the same leeway resistance and turning moment. that makes sense-- only one tip vortex.
it seems then that rudder placement becomes critical, because you need to balance sideslip from the sail with the weather helm caused by the ww hull. all without fine-tuning the CLR with the rudders. too much towards the ends and you geta big turning moment but not much leeway prevention. just the opposite if too much towards the mast.
is it all just guesswork or is there engineering software that can help? i only know of jSDN yacht designer. from a 3D CAD drawing it can calculate COE, CLR, COG, COB, etc. it's not clear to me though if it can compute drag and weather helm and leeway. maybe in the paid version.
woohoo about five proas in the competition! very much looking forward to seeing them all.
ben
--- In harryproa@yahoogroups.com.au, Rob Denney <harryproa@...> wrote:
> 2) It [balestron rig] will have lee helm if you only sail with one rudder. Bi
g deal, at
> least it will steer with 2, I hear you say. And I agree, but once you have
> sailed with one, it becomes pretty compelling, particularly as the bows lift
> up rather than get depressed by the drag on the rudder.
> Look forward to the details. Should be a fun competition. I have now seen
> 4 harryproa entries, plus mine. Plus I bet there will be a bunch of non
> harry proas as well.
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