Subject: Re: [harryproa] Re: Sunday sail
From: jerry freedomev
Date: 2/22/2006, 6:20 AM

                Hi Robert and All,

Robert <> wrote:
-If a crabclaw or lateen rig could be shunted as easily and safely I
would go for them.
        Why not? They are as easy to shunt as most other rigs. It depends on how you make them.
        If one was to use an A frame mast, you could just slide the base of the yard on a track fairly easily.
        And no reason they be slow as Steve Brown and I designed built the Java Cat with Steve doing the shape, layout and I doing the engineering details, used a lanteen rig on it and hit 25kts one night.
         While hard to see, it uses a low set mast that was designed to lower the mast easily as the owner lived behind a low bridge. But the mast was built from ply/epoxy in a foil shape and worked very well. We could raise, lower it in under 5 minutes singlehandedly.
         For proas, you put the A frame base inward of the mast and a track on the leaward deck just like a mainsheet traveler.
With carbon fibre yards and quality cut cloth,
      Why would one need carbon fiber? Wood/epoxy will do wonders and has worked well on the Java for 15 yrs now. A lanteen, Crab claw are inheritly low stress rigs and why they were used early.
      If I was doing a Harry Proa, I'd make a rotating wing mast of wood/epoxy that either had a stub on the bottom of it or fit over an upright stub coming up from the deck to pivot on.  
       And why would 2 smaller masts be harder to take down, put up that a larger single one?
they shouldn't point that much lower and they are a lifting rig to
avoid the perennial problem of a depressed lee bow that no amount of
prozac can fix.
I am more appreciating John Hitch's rigs on his personal catamarans
based on the mast way back and nothing but jibs.
      I can think of few rigs with higher loads and worse windward performance than 2 jibs alone going to weather.
The easy rig is starting to look better. Visionarry seemed to sail
pretty flat

Thankfully the effect of the depressed bow decreases for the same
speed as you get bigger.
         That's only true if you are lighter compared to the bows bouyancy.
This offsets the effect of human ballast
movement decreasing

-- In, carlos Solanilla
<carlosproacarlos@y...> wrote:
> I wonder how feaseable is to buid a una rig for shunting but with a
sliding mast base track so to avoid having a board. It would be
probably more inclined and the base of the sail with a high cut.
> dominiquebovey <dominiquebovey@y...> wrote:  Hi,
> all this looks as if the schooner rig efficiency is much less than
> one of the una rig. My feeling is that the forward sail disturbs the
> rear sail to the point the latter could actually be almost only drag
> and no propulsion.
        While in many mono's that may be true but in lightweight boats that can't go thru waves by weight, inertia, you must fall off somewhat and gain speed to get to windward fastest. So in these and most other points of sail, a 2 sail rig will beat out a single sail rig most of the time.
        Also lower aspect ratio sails on our bosts will usually beat high aspect ratio ones in all round performance. Plus they have much lower stresses, heeling moments making them much safer, easier to handle. 
                     Jerry Dycus

> I would really be interested to see an easy rig compared to the una,
> but I am starting to think it might not be much more efficient than
> the una. But hey, in racing even 0.1kn is something. On class C wing
> masts you almost always have "deflectors" in the wing mast leading
> edge, to force the air going faster on the extrados (depression
> of the wing. In an easyrig the jib plays this role.

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