Subject: Re: [harryproa] Re: Sunday sail
From: "Rob Denney" <proa@iinet.net.au>
Date: 2/9/2006, 8:59 AM
To:
Reply-to:
harryproa@yahoogroups.com.au

Nothing else up my sleeve.  The boat sails well with either one or two sails and only one rudder, although rudder area seems a little small with 2 rigs.  The single rudder is just a way of doing the same thing but without having to go to leeward to lift and lower rudders on each shunt.  It also saves a bit of weight and a remarkable amount of wave drag from the front rudder box.
 
regards,
 
rob
----- Original Message -----
From: Robert
To: harryproa@yahoogroups.com.au
Sent: Thursday, February 09, 2006 8:23 PM
Subject: [harryproa] Re: Sunday sail

--If you can do it, I remember talking to Loch Crowther many years
ago as the natural progression ofthe centre board and the rudder
finally meeting with the rig getting further back.  I have always
admired your ingenuity, bu this is stretching my imagination. The
only thing I can think of is there is enough tracking from the
rockerless hull and weather helm from the depressed bow for an of
centre to aft rudder to work.
You've probably got something else up your sleeve.
Robert

- In harryproa@yahoogroups.com.au, "Rob Denney" <proa@i...> wrote:
>
> G'day,
>
> The natural progression I see is to a single water foil doing both
leeway prevention and steering.  3 foils is a lot more work and drag,
plus more complex to use. 
>
> The twist oscillations are one of a number of things that will be
interesting to see on the raked forward wing mast!
>
> regards,
>
> Rob
>   ----- Original Message -----
>   From: Robert
>   To: harryproa@yahoogroups.com.au
>   Sent: Wednesday, February 08, 2006 10:39 AM
>   Subject: [harryproa] Re: Sunday sail
>
>
>   It seems a natural progression is a single centreboard with fore
and
>   aft but not lateral symmetry that can be pivoted in case of
collision
>   or partly raised. The rudders can then be made smaller and more
>   lightly loaded. Not sure how I'd like a tilted wingmast on a big
>   boat. The twist oscillations could be horrendous.
>
>   robert
>
>   --- In harryproa@yahoogroups.com.au, "Robert" <cateran1949@y...>
>   wrote:
>   >
>   > Rob,
>   >  Is it possible that the decreased resistance by lifting the
>   forward
>   > blade and the raking forward of the rear could contribute to
this?
>   > regards,
>   > Robert
>   >
>   >
>   > --- In harryproa@yahoogroups.com.au, "Rob Denney" <proa@i...>
wrote:
>   > >
>   > > G'day,
>   > >   Hi Rob
>   > >
>   > >   Did you just use one of the schooner's rigs in a new
central
>   hole?
>   > >   Yes
>   > >
>   > >
>   > >   Did you have to restrain the forward rudder or just ignore
it?
>   > >
>   > >   Initially I kept it aligned with the flow (ie restrained
it),
>   but
>   > it was easier to keep the rear one aligned so I steered with
the
>   > front one.   Both took a lot of concentration, so I pulled the
>   front
>   > one up altogether, which was far easier than either.
>   > >
>   > >   Did you move aft to keep the bow up?
>   > >
>   > >   I sat just forward of the aft beam and the angle between
bow
>   and
>   > hull bottom popped into view regularly.  Sitting in the middle
>   > depressed it, but not by much, probably no more than level. 
This
>   is
>   > illogical,  I will check it next time as it is relevant for the
>   > bigger boats where the weight cannot be moved.
>   > >   regards,
>   > >
>   > >   Rob
>   > >
>   > >
>   > >   Regards,
>   > >
>   > >   Col C
>   > >
>   > >
>   > >   --- In harryproa@yahoogroups.com.au, "Rob Denney"
<proa@i...>
>   > wrote:
>   > >   >
>   > >   > G'day,
>   > >   > Went sailing on Sunday in Elementarry to assess una rigs
vs
>   > >   schooners.  15 knots of breeze, solo, with 11 sqm/118 sq'
of
>   > sail. 
>   > >   This is half a Tornado sail area but the sail itself
probably
>   > less
>   > >   than 75% as effective due to the mast and the set up.
>   > >   >
>   > >   > Simply amazing.  It is a different boat. Flies over the
water
>   > >   rather than trying to force it's way through it.    Steered
>   > itself,
>   > >   the bows were up upwind and top speed was not a lot
different
>   to
>   > the
>   > >   schooner rig (16.4 knots max, vs 16.8 with the schooner in
>   > similar
>   > >   conditions).  Followed a Tornado upwind, was pointing as
high,
>   > but
>   > >   going slower.  Quicker than a racing Hobie 16 reaching.  
Not
>   > many
>   > >   other boats were sailing.  Not much sea, but occasional
large
>   > wakes
>   > >   from powerboats.  Handled with aplomb, although wet if the
beam
>   > hits
>   > >   the wave top.
>   > >   >
>   > >   > I steered using only the aft rudder which was similar to
>   > steering
>   > >   a conventional boat, the forward location making up for no
>   > >   daggerboard, the oversize rudder making up for the lack of
>   lever
>   > >   arm.   Shunting was very easy (a nuisance going to leeward
to
>   > lift
>   > >   and lower the rudders), never got close to getting into
irons
>   or
>   > >   caught aback.   Downwind, it just got up and went. 
>   Occasionally
>   > >   buried the bow, but did not slow it down.    It is now
>   definitely
>   > a
>   > >   boat anyone could sail solo and one which I look forward to
>   > teaching
>   > >   my 4 year old daughter how to sail on.  Should also be able
to
>   > look
>   > >   at the gps while sailing, rather than only the max speed at
the
>   > end
>   > >   of the day. 
>   > >   >
>   > >   > Interestingly, I only flew a hull once or twice the whole
>   time
>   > >   (too lazy to get off the windward hull, too amazed by how
>   > >   comparatively easy it all was to bother with pushing the
>   limits),
>   > >   which suggests that the rig is under utilised, something
>   > supported
>   > >   by looking at it.  A new wing mast will help this.  I was
going
>   > to
>   > >   increase the una rig sail area, but think I will go with
the
>   same
>   > >   area, but with a wing mast, maybe forward raked to reduce
sheet
>   > >   loads.  Also building a single rudder setup so I don't have
to
>   > raise
>   > >   and lower them each shunt.
>   > >   >
>   > >   > The single rig is quicker to rig and derig; An hour and a
>   half
>   > >   from arriving at the ramp to sailing, but at least half of
this
>   > was
>   > >   one off jobs that needed doing.  Also easier to right after
a
>   > >   capsize and 4 grand cheaper.
>   > >   >
>   > >   > I am not a lot wiser about how long boats should be for a
>   given
>   > >   sail area, but am pretty certain that it is much longer
than
>   they
>   > >   currently are. 
>   > >   >
>   > >   > I think this was not so much a comparison between
schooner
>   and
>   > >   una, more between lots of sail and less, although 2 is
>   definitely
>   > >   twice the effort of one. 
>   > >   >
>   > >   > Apologies for cross posting.
>   > >   >
>   > >   > regards,
>   > >   >
>   > >   > rob
>   > >   >
>   > >
>   > >
>   > >
>   > >
>   > >
>   > >
>   > >
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