-I have been in boats at 25 knots in lumpy seas. I don't think I would
have a marriage left if I regarded this as normal part of cruising. It
is amazing how hard water feels at that speed. If I could cruise at 15
knots so comfortably I would be more than happy, and if I could drive
into choppy seas without the crew chundering their guts out, it would
improve marital harmony and allow more hours on the water.
I can understand Todd's trepidation about the depths of the bows but
there is no point in having any more than to provide enough bouyancy
to lift the stern. Any more and you increase windage and frontal
resistance with no advantage. Increased frontal resistance as you
drive into a wave slows the boat down, and if going down wind
increases the apparent wind, increasing the chance of pitch poling.
The only case where I am in two minds about the lack of rocker is when
surfing down waves in shallow water. There is the longer effective
waterline and therefore less of an angle against the greater depthe of
the bows digging into the bottom. I think on balance I am happy the
longer effective length and good early bouyancy in the bows allied
with a light boat
One of the difficulties of a double ended vessel is the compromise
between being a bow and a stern and I don't think this is yet
optimised, as I think Rob and Mark would agree, but the bow/sterns
still work pretty well as they are. I have a few wayout ideas I'd
like to try myself, with a stepped reverse sheer, slightly wider down
low and a slight V underneath. I do not necessarily think it will be
an improvement but might be fun to see what happens.
Robert
-- In harryproa@yahoogrou
>
> The boat sails remarkable flat with very little pitch. I expected
her to dig
> her bow in more but the absence of rocker really does make a boat pitch
> stable. She was nowhere near her limit.
>
> The seas were sedate with westerly winds on an east coast. Lots of
fun. I
> don't think large seas would prove much of a problem with the bows
but would
> create more drag at the rudders. We are using beam mounted rudders on
> Solitarry and if proven will use them on other models. I'm confident the
> existing rudder brackets are plenty strong enough to take vertical
pounding.
> As Robert pointed out, if the brackets can take the enormous loads
imparted
> by the huge leverage of the daggerboards, vertical sea loadings are
minor.
>
> Why do you want to go 25 knots in lumpy seas? Is this a personal
ambition or
> just an armchair curiosity? Rare Bird was designed as a cruising
boat and as
> such will probably never go that fast. Solitarry is a different
beast and
> when she is built we hope to satisfy your curiosity.
>
> So Todd, you are going to have to sit back in your armchair, be
patient and
> wait and see.
>
> Cheers,
> Mark
>
>
> ............
> Mark Stephens
> www.harryproa.
>
> -----Original Message-----
> From: harryproa@yahoogrou
[mailto:harryproa@yahoogrou
> Behalf Of Todd
> Sent: Thursday, 9 August 2007 12:41 PM
> To: harryproa@yahoogrou
> Subject: [harryproa] Re: Rare Bird Sailing
>
>
>
> No I don't think a flared bow would be any better.It would be worse.
> The boat doesn't look to be sailing flat. It looks to me to be
> heeled 5 to 7 degrees maybe more in the video. To me the leeward
> hull just seems to shallow at the ends. In the 1 metre swell the bow
> is punch through on a few all most buried. The video shows pretty
> sedate sea state and the boat looks all ready to be pushing its
> limits with the leeward hull low in the water. Along with the
> appendage attachments. Load of rudders horizontally and vertical in
> proper trim but what about at speed, 20knots being pounded
> vertically hour after hour. In and out wave after wave?
>
> Good at 15 knot winds 15 knot boat speed but what at 20 to 25 knots
> in lumper seas?
>
> Todd
>
> --- In harryproa@yahoogrou <mailto:harryproa%
> ps.com.au, "Robert" <cateran1949@
> wrote:
> >
> > The boat looks as though it is riding pretty flat to me . With 3m
> > swell I am assuming the bow will simply punch into it and gently
> rise
> > without any violent hobby horsing. The flat ride should keep the
> sails
> > working better than with violent motion of a flared bow bouncing
> off
> > waves I can't think of any small boat that would not be pretty wet
> in
> > the same circumstances. The braces are designed to take the loads
> of
> > the rudders. Shock loads from the braces hitting the top of the
> wave
> > is nothing compared to loads from the rudders,
> > Robert
> > --- In harryproa@yahoogrou <mailto:harryproa%
> ps.com.au, "Todd" <bitme1234@> wrote:
> > >
> > > --- In harryproa@yahoogrou <mailto:harryproa%
> ps.com.au, "Todd" <bitme1234@> wrote:
> > > >
> > > > Hello Rob and folks, (sorry about that)
> > > >
> > > > Nice video, impressive. But;) Looks like 1 metre swell
> possible in
> > > > 15 knot winds for a boat speed of 15knots . Marshall Island
> Walap
> > > > will do that. What about 25 knot winds in 3 metre swell? Looks
> as
> > > > throught the bow is pretty close to the edge in 15 knots. As
> far
> > > as
> > > > all out performance pushing the boat to the limits what is
> known?
> > > >
> > > > What about the braces for the weather boards, how much abuse
> will
> > > > they handle being punched from underneath or swist from
> changing
> > > > angle of attacks in certain situations. The bottom brace seems
> > > > really close to the water surface.
> > > >
> > > > Todd
> > > >
> > > > --- In harryproa@yahoogrou <mailto:harryproa%
> ps.com.au, "Rob Denney" <harryproa@>
> > > > wrote:
> > > > >
> > > > > G'day,
> > > > >
> > > > > My Harry did 15 in 15 with lousy sails, but not much
> interior,
> > > so
> > > > probably
> > > > > pretty similar. Blind Date will be faster than Rare Bird as
> it
> > > is
> > > > lighter,
> > > > > has less windage and a stiffer mast. Rare Bird's sails also
> > > need
> > > > some work,
> > > > > it has not realised it's full potential yet.
> > > > >
> > > > > The only real difference in a Harry is whether you have the
> > > > cockpit cover or
> > > > > not. Bain has it and it works well. I prefer to feel the
> > > breeze,
> > > > so the
> > > > > solo boat will have a pram type fold up cloth cover over
> part of
> > > > the cockpit
> > > > > for keeping out of the rain and wind.
> > > > >
> > > > > regards,
> > > > > Rob
> > > > >
> > > > >
> > > > > On 8/8/07, George Kuck <chesapeake410@
> > > > > >
> > > > > > How will the 12m (40') Harry (built with the KSS
> method)
> > > > performance
> > > > > > compare to Rare Earth or Blind Date ? Will it have
> > > a "cruiser"
> > > > or "sport"
> > > > > > version option or be a compromise between the two ?
> > > > > >
> > > > > > George Kuck
> > > > > > Chestertown, MD
> > > > > >
> > > > > > *Robert <cateran1949@
> > > > > >
> > > > > > It is pretty impressive for such a comfortable boat. Even
> > > with
> > > > the
> > > > > > extra weight it is still pretty light compared to most
> > > > multihulls of
> > > > > > similar length,
> > > > > > \ Robert
> > > > > >
> > > > > > --- In harryproa@yahoogrou
<mailto:harryproa%
> ps.com.au <harryproa%
> > > > 40yahoogroups.
> > > > > > Crawford <jmichael@> wrote:
> > > > > > >
> > > > > > >
> > > > > > > Fifteen knots in fifteen knots of wind? In Rare Bird?
> Holy
> > > > moly!
> > > > > > >
> > > > > > .
> > > > > >
> > > > > >
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>
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